WO2012150220A1 - Radiolabeled amino acids for diagnostic imaging - Google Patents

Radiolabeled amino acids for diagnostic imaging Download PDF

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WO2012150220A1
WO2012150220A1 PCT/EP2012/057925 EP2012057925W WO2012150220A1 WO 2012150220 A1 WO2012150220 A1 WO 2012150220A1 EP 2012057925 W EP2012057925 W EP 2012057925W WO 2012150220 A1 WO2012150220 A1 WO 2012150220A1
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Prior art keywords
fert
butyl
benzyl
butoxycarbonyl
alkylene
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PCT/EP2012/057925
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French (fr)
Inventor
Mathias Berndt
Andre Müller
Heribert Schmitt-Willich
Timo Stellfeld
Georg Kettschau
Thomas Brumby
Keith Graham
Lutz Lehmann
Jorma Hassfeld
Martin Krüger
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Bayer Pharma Aktiengesellschaft
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Priority to EP12719351.4A priority Critical patent/EP2705012A1/en
Application filed by Bayer Pharma Aktiengesellschaft filed Critical Bayer Pharma Aktiengesellschaft
Priority to SG2013081427A priority patent/SG194761A1/en
Priority to JP2014508763A priority patent/JP2014519489A/en
Priority to MX2013012793A priority patent/MX2013012793A/en
Priority to RU2013153130/04A priority patent/RU2013153130A/en
Priority to US14/115,471 priority patent/US9238631B2/en
Priority to KR1020137031671A priority patent/KR20140060466A/en
Priority to AU2012251737A priority patent/AU2012251737A1/en
Priority to CN201280033267.XA priority patent/CN103827057A/en
Priority to CA2835015A priority patent/CA2835015A1/en
Publication of WO2012150220A1 publication Critical patent/WO2012150220A1/en
Priority to IL229179A priority patent/IL229179A0/en
Priority to ZA2013/08188A priority patent/ZA201308188B/en

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Abstract

This invention relates to novel compounds suitable for labeling by 18F and to the corresponding 18F labeled compounds themselves, 19F-fluorinated analogues thereof and their use as reference standards, methods of preparing such compounds, compositions comprising such compounds, kits comprising such compounds or compositions and uses of such compounds, compositions or kits for diagnostic imaging by Positron Emission Tomography (PET).

Description

RADIOLABELED AMINO ACIDS FOR DIAGNOSTIC IMAGING
FIELD OF INVENTION
This invention relates to novel compounds suitable for 18F-labeling and to the corresponding 8F-labeled compounds, 19F-fluorinated analogues thereof and their use as reference standards, methods for preparing 18F-labeled compounds, methods for preparing 9F-fluorinated analogues, compositions comprising such compounds and/or analogues, kits comprising such compounds and/or analogues, and uses of 18F-labeled compounds for Positron Emission Tomography (PET) imaging of proliferative diseases such as tumor.
BACKGROUND
Molecular imaging has the potential to detect disease progression or therapeutic effectiveness earlier than most conventional methods in the fields of oncology, neurology and cardiology. Of the several promising molecular imaging technologies having been developed as optical imaging and MRI, PET is of particular interest for drug development because of its high sensitivity and ability to provide quantitative and kinetic data.
For example, positron emitting isotopes include carbon, iodine, fluorine, nitrogen, and oxygen. These isotopes can replace their non-radioactive counterparts in target compounds to produce tracers that function biologically and are chemically identical to the original molecules for PET imaging, or can be attached to said counterparts to give close analogues of the respective parent effector molecule. Among these isotopes 18F is the most convenient labeling isotope due to its relatively long half life (1 10 min) which permits the preparation of diagnostic tracers and subsequent study of biochemical processes. In addition, its high β+ yield and low β+ energy (635 keV) are also advantageous.
The 18F-fluorination reaction is of great importance for 18F-labeled radiopharmaceuticals which are used as in vivo imaging agents targeting and visualizing diseases, e.g. solid tumours or diseases of brain. A very important technical goal in using 8F-labeled radiopharmaceuticals is the rapid preparation and administration of the radioactive compound due to the fact that the 8F isotopes have a half-life of about 1 10 minutes that is beneficial for clinical use on the one hand, but is challenging for production processes of such compounds on the other hand. The best known example for PET imaging of diseases is 2-[18F]fluorodeoxyglucose (p8F]FDG), which is the most widely used PET radiopharmaceutical [J Nucl Med (1978), 19: 1 154-1 161 ]. However, a number of pitfalls and artifacts have been ascribed to FDG imaging and more continue to surface as the worldwide experience with FDG increases. Altered FDG uptake in muscles, brown adipose tissue, bone marrow, the urinary tract, and the bowel is demonstrated in a significant proportion of patients, which can hide underlying malignant foci or mimic malignant lesions (Seminars in Nuclear Medicine, 40, 283 (2010)). Although PET is a sensitive tool for detecting malignancy, FDG uptake is not tumor specific. It can also be seen in healthy tissue or in benign disease as inflammation or posttraumatic repair and could be mistaken for cancer. The experienced nuclear medicine physician mostly manages to differentiate malignant from non-malignant FDG uptake, but some findings may remain ambiguous (Euro. Radio., 16, 1054 (2006)).
The area most common for interpretative pitfalls with FDG is related to uptake in active skeletal muscle. Many benign conditions can cause high accumulation of FDG creating the potential for false positive interpretation. Such pitfalls include variable physiologic FDG uptake in the digestive tract, thyroid gland, skeletal muscle, myocardium, bone marrow, and genitourinary tract and benign pathologic FDG uptake in healing bone, lymph nodes, joints, sites of infection, and cases of regional response to infection and aseptic inflammatory response. In many instances, these physiologic variants and benign pathologic causes of FDG uptake can be specifically recognized and properly categorized; in other instances, such as the lymph node response to inflammation or infection, focal FDG uptake is non-specific (J. Nucl. Med. Tech. 33, 145 (2005), Radiographics, 19, 61 (1999), Seminars in Nuclear Medicine, 34, 122 (2004); 34, 56 (2004), J. Nucl. Med. 45, 695 (2004)).
To overcome at least some of these limitations of FDG, other adaptations of the tumor metabolism beyond enhanced glycolysis need to be exploited to provide an improved PET imaging agent for tumors. Tumors in general often have to cope with severe conditions of oxidative stress. Thiol containing molecules like the amino acid L-cysteine and the tripeptide glutathione (GSH) are the major cellular components to overcome these conditions and are consumed for detoxification of reactive oxygen species (ROS) and other electrophiles, such as chemotherapeutics. Thus, a continuous supply of GSH and its precursors are critical for cell survival and provide a selective advantage for tumor growth. L-Cysteine plays a key role as reactive oxygen species scavenger by itself and is the rate-limiting building block for GSH biosynthesis. In the blood the oxidized dimer L-cystine is the dominant form and the availability of L-cysteine is limited. However, L-cystine can be efficiently provided to cells via the cystine / glutamate exchanger xCT (SLC7A1 1 ). Subsequently L-cystine is reduced inside the cells to yield two molecules of L-cysteine. An increased xCT expression is found in many tumors. The xCT transporter was first described by Bannai and Kitamura in 1980 as a Na*- independent, high-affinity transporter for L-cystine and L -glutamate in human fibroblasts (J. Biol. Chem. 255 (1980) 2372-2376). It is a heteromeric amino acid transporter for anionic amino acids and the main transporter for L-cystine (Pflugers Arch 442 (2001 ) 286-296, Pflugers Arch 447 (2004) 532-542). It is important to note that the xCT transporter is not able to discriminate between its natural substrates L-cystine and L- glutamate for the inward directed transport (Neuropharmacology 46 (2004) 273-284). Radiolabeled amino acid derivatives targeting the xCT transporter have been described before. [ 8F]fluoroalkyl- and [18F]fluoroalkoxyl- substituted glutamic acid derivatives are disclosed in WO2008052788, WO2009141091 , WO2009141090. Furthermore, WO2009141090 comprises fluorobenzyl- and fluoropyridylmethyl- substituted glutamic acid derivatives.
As one example, 4-(3-[ 8F]fluoropropyl)glutamic acid was shown to be a promising agent for tumor imaging (WO2009141091 , example 4). A biodistribution study in A549 tumor bearing nude mice demonstrated very good tumor targeting (1 .6%ID/g at 1 h post injection), Kidney (6.4 %ID/g at 30 min post injection) and pancreas (8.5 % I D/g at 30 min post injection) were found to be the non-tumor organs with highest tracer uptake. Beside 18F labeled glutamic acid derivatives, also 18F labeled cystine derivatives were investigated regarding the potential to target xCT activity in tumors (WO2010125068). However, it is well known, that the uptake of L-cystine is pH dependent, with less uptake at low pH as typically found in tumor environment. In contrast, uptake of glutamate and its derivatives via xCT is independent of pH (J Biol Chem 256 (1981 ) 5770-5772).
Due to the half life of 8F isotope of about 1 10 min, an 8F radiopharmaceutical demands a daily production. Key factor for successful routine use of such radiotracer are a robust and high yield radiosynthesis on the one hand and reliable and fast analytical methods for determination of radiochemical purity, specific activity and byproducts. Well established analytical methods comprise liquid chromatography (e.g. HPLC, UPLC) using radiodetector and UV-detector.
A drawback of the most promising 8F labeled xCt substrates described so far is a missing chromophor to enable a standard detection by UV detectors. To measure specific activity or presence of by-products, derivatization methods (e.g. pre-column derivatization. post-column derivatization) using for example OPA, ACCQ, Fmoc, Ninhydrin reagents can be used. However, a simple direct analysis of the radiopharmaceutical compositions would be advantageous.
PROBLEM TO BE SOLVED
PET imaging agents for detection of proliferative diseases such as tumors are needed that:
Have high tumor uptake and retention,
- Have no or minor uptake in non-tumor tissue,
Provide improved specificity, e.g regarding tumor vs. inflammation,
Is synthesized in a simple and robust way to enable widespread use inclusive standard quality control methods for safe and simple release of the radiopharmaceuticals. 8F labeled substrates of the xCT transporter systems described so far showed moderate to good tumor uptake, but:
Showed retention in non-tumor tissues (e.g. pancreas, kidneys) as well and/or Demand special analytical methods to for determination of specific activity and detection of non-radioactive (and non-UV active) by-products.
The new compounds described herein are specific xCT transporter substrates (see Example 71 ). The new radiolabeled derivatives show high tumor uptake and retention (e.g [18F]-1 , [ 8F]-12, [18F]-41 and [18F]-52) with high contrast due to favorable clearance and low uptake in healthy tissues. In contrast to FDG used for tumor imaging so far, compounds described herein demonstrate reduced uptake in inflammatory lesions and improved washout (see Example 80).
Another feature of the compounds described herein is the possibility of using relatively simple and straight forward analytical methods due to the chromophor of the arylene or heteroarylene moieties within the chemical structures of the compounds of the present invention.
SUMMARY
Figure imgf000006_0001
Figure imgf000006_0002
VI
The invention furthermore provides a radiopharmaceutical composition of compounds of Formula III or pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, solvates and prodrugs thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipient.
The compounds of Formula III and Formula VI may exist as zwitterions. All forms of the compounds, including free acid, free-base and zwitterions, are contemplated to be within the scope of the present invention. It is well known in the art that compounds containing both amino and carboxyl groups often exist in equilibrium with their zwitterionic forms. Thus, any of the compounds described herein throughout that contain, for example, both amino and carboxyl groups, also include reference to their corresponding zwitterions. The present invention also provides methods for manufacturing of compounds of Formula III:
Figure imgf000007_0001
Figure imgf000007_0002
18F radiolabeling of compounds of Formula I to obtain compounds of Formula II, and
Cleavage of protecting groups of compounds of Formula II to obtain compounds of Formula III.
Indirect method:
Figure imgf000008_0001
Reacting of compounds of Formula IV with a 8F radiolabeled building block, and
Optionally, cleaving of protecting groups to obtain compounds of Formula III. The present invention also provides methods for manufacturing of compounds of Formula VI:
Method 1 :
19F Fluorination of compounds of Formula I to obtain compounds of Formula V,
Cleavage of protecting groups of compounds of Formula V to obtain compounds of Formula VI.
Method 2:
Reacting of compound of Formula IV with a 19F fluorine reagent or 9F fluorinated building block,
Optionally, cleaving of protecting groups.
DETAILED DESCRIPTION
The first aspect of the present invention is directed to compounds of Formula I:
Figure imgf000009_0001
wherein,
R1 is a carboxyl protecting group,
R2 is a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2,
Figure imgf000009_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H.
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*, g) (R6-0),(R7-0)-disubstituted alkylene, h) (R6-0),(R7-0)-disubstituted aikylene-O*, and
«) (CH2CH20)n-CH2CH?-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a) hydrogen or
b) hydroxyl protecting group,
R7 is
a) hydrogen or b) hydroxy! protecting group,
LG is a leaving group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula I:
Figure imgf000010_0001
I
wherein,
R1 is a carboxyl protecting group,
R2 is a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2,
Figure imgf000010_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxyl protecting group, R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxy! protecting group,
LG is a leaving group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula I:
Figure imgf000011_0001
I
wherein,
R1 is a carboxyl protecting group,
R2 is a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2, and
Figure imgf000011_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-NTH,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3, * indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy! protecting group,
R6 is
a) hydrogen or
b) hydroxyl protecting group,
R7 i I:S
a) hydrogen or
b) hydroxyl protecting group,
LG is a leaving group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
Preferred features of invention and embodiments thereof:
Preferably, R1 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, ferf-butyl, a!lyl. benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R1 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) ferf-butyl.
Even more preferably, R1 is ferf-butyl.
Preferably, R2 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, ferf-butyl, ally!, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R2 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) ferf-butyl.
Even more preferably, R2 is ferf-butyl.
Preferably, R1 and R2 are identical.
Preferably, R3 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyi (Moz or MeOZ), ferf-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3.4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenyimethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R3 is selected from the group comprising:
a) hydrogen,
b) fert-butyloxycarbonyl (Boc), and
c) triphenyimethyl (Trityl).
More preferably R3 is selected from the group comprising:
a) iert-butyloxycarbonyl (Boc), and
b) triphenyimethyl (Trityl).
Preferably, R4 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), fert-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenyimethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R4 is selected from the group comprising:
a) hydrogen,
b) ferf-butyloxycarbonyl (Boc), and
c) triphenyimethyl (Trityl).
More preferably R4 is selected from the group comprising:
a) fert-butyloxycarbonyl (Boc) and
b) triphenyimethyl (Trityl).
Additionally, R3 and R4 optionally form an amine-protecting group resulting in NR3R4 being 1 ,3-dioxo-1 ,3-dihydro-2H-isoindol-2-yl (phthalimido) or an azido group.
Preferably, R3 is hydrogen and R4 is an amine protecting group.
More preferably, R3 is hydrogen and R4 is ferf-butyloxycarbonyl (Boc).
More preferably, R3 is hydrogen and R4 is triphenyimethyl (Trityl).
Preferably, R3 and R4 are never Hydrogen at the same time.
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2. Preferably A is d-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene.
Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl Q is a pyridylene as defined below
Figure imgf000014_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to L. Preferably, L is selected from the group comprising:
a) C2-C6 alkylene,
b) C2-C6 alkylene-0*,
c) C2-C6 alkylene-N*H,
d) Cs-Ce cycloalkylene-O*,
e) (R5-0)-substituted C2-C6 alkylene,
f) (R5-0)-substituted C3-C6 alkylene-0*,
g) (R6-0),(R7-0)-disubstituted C3-C6 alkylene,
h) (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3.
* indicates the position of the bond to Q.
More preferably, L is selected from the group comprising:
a) propylene,
b) propylene-O*,
c) ethylene-O*.
d) propylene-N*H,
e) cyclobutylene-O*,
Figure imgf000015_0001
indicates the position of the bond to Q and * indicates the position of the bond to LG.
If L is alkylene, L is preferably Ci alkylene or linear or branched C2-C6 alkyl preferably, L is C2-C3 alkylene selected from ethylene and propylene.
Preferably, L is propylene.
Preferably, L is ethylene.
Preferably, L is methylene.
If L is alkylene-O* L is preferably Ci alkylene-O* (methylene-O*) or linear or branched C2-C6 alkylene-O*. More preferably, L is C2-C3 alkylene-O* is selected from ethylene-O* and propylene-O*.
Preferably, L is propylene-O*.
Preferably, L is ethylene-O*.
Preferably, L is methylene-O*.
If L is alkylene-N*H L is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L is C2-C3 alkylene-N*H, selected from ethylene-N*H and propylene-N*H.
Preferably, L is propylene-N*H.
Preferably, L is ethylene-N*H. Preferably, L is methylene-N*H.
"Aikylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, aikylene is Ci aikylene or C2-C6 aikylene. More preferably, aikylene is C2-C3 aikylene or C4-C6 aikylene.
The same applies to C2-C6 alkylene-O* and C2-Ce alkylene-NH*.
"Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L is cycloalkylene-O* L is preferably Cs-Ce cycloalkylene-O* such as cyclopropylene- O*, cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
is
Figure imgf000016_0001
* indicates the position of the bond to LG. If L is (R5-0)-substituted C2-C6 aikylene, (R5-0)-substituted C3-C6 alkylene-O*, (R6- 0),(R7-0)-disubstituted C3-C6 aikylene, or (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O*, L is preferably an aikylene defined as above bearing one or two protected or unprotected hydroxy I groups. Preferably, L is (R -0)-substituted Cs-Ce alkylene-O* selected from
Figure imgf000016_0002
Preferably, L is (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O* selected from
Figure imgf000017_0001
* indicates the position of the bond to Q, * indicates the position of the bond to LG.
Preferably, R5 is a hydroxyl protecting group.
Preferably, R6 and R7 are hydroxyl protecting groups.
Additionally, R6 and R7 optionally form together one-diol protecting group.
Preferably, hydroxyl protecting group is selected from the group of t-butyl, benzyl, p- methoxybenzyl, p-nitrobenzyl, allyl, trityl, methoxymethyl, methoxyethoxymethyl, ethoxyethyl, 1 -methyl-1 -methoxyethyl, tetrahydropyranyl, trialkylsilyl; benzoyl, acetyl, and phenylacetyl. More preferably, hydroxyl protecting group is t-butyl.
Preferably LG is a leaving group selected from the group comprising:
a) sulfonate leaving group, and
b) halogen.
More Preferably LG is selected from the group comprising:
a) methylsulfonyloxy,
b) (4-methylphenyl)sulfonyloxy.
Even more preferably, LG is methylsulfonyloxy.
Even more preferably, LG is (4-methylphenyl)sulfonyloxy.
Compounds of Formula I are defined by the general formula and/or the combination of the preferred features as defined above.
In a first embodiment, compounds of the formula I are defined as compounds of Formula 1-1 , See structure in table A.
In a second embodiment, compounds of the formula I are defined as compounds of Formula I-2, See structure in table A. In a third embodiment, compounds of the formula I are defined as compounds of Formula 1-3, See structure in table A.
In a fourth embodiment, compounds of the formula I are defined as compounds of Formula 1-4, See structure in table A.
In a fifth embodiment, compounds of the formula I are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula 1-1 , Formula I-2,
Formula I-3 and Formula I -4 including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments. Table A: Formula I stereoisomers
Figure imgf000018_0001
I-3 I-4
The compounds of Formula 1-1 , Formula I-2, Formula I -3 and, Formula I -4 furthermore encompass pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, and solvates thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipients.
A preferred compound of Formula I is di-ferf-butyl /V-(ferf-butoxycarbonyl)-4-{4-[2- (tosyloxy)ethoxy]benzyl}glutamate:
Figure imgf000019_0001
Another preferred compound of Formula I is di-fert-butyl V-(tert-butoxycarbonyl)-4-{4-[3-
Figure imgf000019_0002
Another preferred compound of Formula I is di-fert-butyl V-(fert-butoxycarbonyl)-4-{4-[3-
Figure imgf000019_0003
Another preferred compound of Formula I is di-fert-butyl A/-(fert-butoxycarbonyl)-4-(4- {[3-(tosyloxy)propyl]amino}benzyl)glutamate:
Figure imgf000019_0004
Another preferred compound of Formula I is di-fert-butyl /V-(fer -butoxycarbonyl)-4-(4- {[3-(tosyloxy)cyclobutyl]oxy}benzyl)glutamate:
Figure imgf000020_0001
Another preferred compound of Formula I is di-tert-butyl N-(tert-butoxycarbonyl)-4-{4- -yl)oxy]benzyl}glutamate:
Figure imgf000020_0002
Another preferred compound of Formula I is di-fert-butyl V-(ferf-butoxycarbonyl)-4-(3-{4-
Figure imgf000020_0003
Another preferred compound of Formula I is di-fert-butyl /V-(ferf-butoxycarbonyl)-4-(3-{4-
Figure imgf000020_0004
Another preferred compound of Formula I is di-ferf-butyl 2-[(ferf-butoxycarbonyl)amino]- 5-{4-[2-(tosyloxy)ethoxy]benzyl}hexanedioate:
Figure imgf000021_0001
Another preferred compound of Formula I is di-iert-butyl V-(ferf-butoxycarbonyl)-4-({5- -(tosyloxy)propyl]pyridin-2-yl}methyl)-glutamate:
Figure imgf000021_0002
A more preferred compound of Formula I is di-iert-butyl (4S)-/V-(ferf-butoxycarbonyl)-4-
Figure imgf000021_0003
Another more preferred compound of Formula I is di-iert-butyl (4S)-/V-(fert-butoxy-
Figure imgf000021_0004
Another more preferred compound of Formula I is di-iert-butyl (4S)-/V-(fert-butoxy- carbonyl)-4-{4-[3-(tosyloxy)propyl]benzyl}-L-glutamate:
Figure imgf000022_0001
Another more preferred compound of Formula I is di-iert-butyl (4S)- V-(ferf-butoxy- carbonyl)-4-(4-{[3-(tosyloxy)propyl]amino}benzyl)-L-glutamate:
Figure imgf000022_0002
Another more preferred compound of Formula I is di-fert-butyl (4S)- V-(fert-butoxy- carbonyl)-4-(4-{irans-[3-(tosyloxy)cyclobutyl]oxy}benzyl)-L-glutamate:
Figure imgf000022_0003
Another more preferred compound of Formula I is di-fert-butyl (4S)-A-(fert-butoxy- carbonyl)-4-(3-{4-[2-(tosyloxy)ethoxy]phenyl}propyl)-L-glutamate:
Figure imgf000022_0004
Another more preferred compound of Formula I is di-fert-butyl (4S)-/V-(fert-butoxy- carbonyl)-4-(3-{4-[3-(tosyloxy)propyl]phenyl}propyl)-L-glutamate:
Figure imgf000023_0001
Another more preferred compound of Formula I is di-ferf-butyl (2S)-2-[(ferf-butoxy- ate:
Figure imgf000023_0002
Another more preferred compound of Formula I is di-ferf-butyl (2R)-2-[(ferf-butoxy- ate:
Figure imgf000023_0003
Another more preferred compound of Formula I is di-ferf-butyl (4R)-N-(tert- yl)-L-glutamate:
Figure imgf000023_0004
The second aspect of the present invention is directed to compounds of Formula III:
Figure imgf000024_0001
wherein
X is selected from the group comprising
a) CH2,
Figure imgf000024_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene.
b) alkylene-O*,
c) alkylene-ΝΉ,
d) cycloalkylene-O*,
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula III:
Figure imgf000024_0003
wherein
X is selected from the group comprising
a) CH2,
Figure imgf000025_0001
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O*.
c) alkylene-N*H,
d) cycloalkylene-O*,
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula III:
Figure imgf000025_0002
wherein
X is selected from the group comprising
a) CH2, and
b) CH2-CH2,
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O*, c) alkylene-N*H,
d) cycloalkylene-O*,
e) monohydroxyalkylene.
f) monohydroxyalkylene-O*.
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
Preferred features of invention and embodiments thereof:
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2.
Preferably, A is Ci-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene.
Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl Q is a pyridylene as defined below
Figure imgf000026_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to L1
Preferably, L1 is selected from the group comprising:
a) C2-Ce alkylene,
b) C2-C6 alkylene-0*,
c) C2-C6 alkylene-N*H, d) C3-C6 cycloalkylene-O*.
e) monohydroxy C2-C6 alkylene,
f) monohydroxy C3-C6 alkylene-O*,
g) dihydroxy Ca-Ce alkylene,
h) dihydroxy C4-C6 alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1
* indicates the position of the bond to Q.
More preferably, L1 is selected from the group comprising:
a) propylene,
b) propylene-O*,
c) ethylene-O*,
d) propylene-N*H,
e) cyclobutylene-O*,
Figure imgf000027_0001
indicates the position of the bond to Q and # indicates the position of the bond to 18F. If L1 is alkylene, L1 is preferably linear or branched C2-Ce alkylene. More preferably, L1 is C2-C3 alkylene selected from ethylene and propylene.
Preferably, L1 is propylene.
Preferably, L is ethylene.
Preferably, L is methylene.
If L1 is alkylene-O* L1 is preferably Ci alkylene-O* (methylene-O*) or linear or branched
C2-C6 alkylene-O*. More preferably, L1 is C2-C3 alkylene-O* is selected from ethylene-
O* and propylene-O*.
Preferably, L1 is propylene-O*.
Preferably, L1 is ethylene-O*. Preferably, L is methylene-O*.
If L1 is alkylene-N*H L1 is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L1 is C2-C3 alkylene-N*H, selected from ethylene-N*H and propylene-N*H.
Preferably, L1 is propylene-N*H.
Preferably, L is ethylene-N*H.
Preferably, L is methylene-N*H. "Alkylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, alkylene is Ci alkylene or C2-C6 alkylene. More preferably, alkylene is C2-C3 alkylene or C_-Ce alkylene.
The same applies to C2-C6 alkylene-O* and C2-Ce alkylene-NH*.
"Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L1 is cycloalkylene-O* L1 is preferably Cs-Ce cycloalkylene-O* cyclopropylene-O*, cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
1 is
Figure imgf000028_0001
* indicates the position of the bond to 8F.
If L1 is a monohydroxy C2-C6 alkylene, monohydroxy Cs-Ce alkylene-O*, dihydroxy Cs-Ce alkylene, or dihydroxy Ci-Ce alkylene-O*, L1 is preferably an alkylene as defined above bearing one or two hydroxy I groups. Preferably, L1 is monohydroxy Cs-Ce alkylene-O* selected from
Figure imgf000028_0002
Preferably, L1 is dihydroxy C4-C6 alkylene-O* selected from
Figure imgf000029_0001
* indicates the position of the bond to Q, * indicates the position of the bond to 8F.
Compounds of Formula III are defined by the general formula and/or the combination of the preferred features as defined above.
In a first embodiment, compounds of the formula III are defined as compounds of Formula III-1 , See structure in table B.
In a second embodiment, compounds of the formula III are defined as compounds of Formula lli-2, See structure in table B.
In a third embodiment, compounds of the formula III are defined as compounds of Formula III-3, See structure in table B.
In a fourth embodiment, compounds of the formula III are defined as compounds of Formula III-4, See structure in table B.
In a fifth embodiment, compounds of the formula III are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula MM , Formula III-2. Formula III -3 and Formula III-4 including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments.
Table B: Formula III stereoisomers
Figure imgf000029_0002
1-1 I-2
Figure imgf000030_0001
ilI-3 111-4
The compounds of Formula 111-1 , Formula III-2. Formula III -3 , Formula III-4 furthermore encompass pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, and solvates thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipients.
The compounds of Formula III may exist as zwitterions. All forms of the compounds, including free acid, free-base and zwitterions, are contemplated to be within the scope of the present invention. It is well known in the art that compounds containing both amino and carboxyl groups often exist in equilibrium with their zwitterionic forms. Thus, any of the compounds described herein throughout that contain, for example, both amino and carboxyl groups, also include reference to their corresponding zwitterions.
III is 4-[4-(2-[ 8F]fluoroethoxy)benzyl]glutamic acid:
Figure imgf000030_0002
Another preferred compound of Formula III is 4-[4-(3-[ 8F]fluoropropoxy)benzyl]glutamic
Figure imgf000030_0003
Another preferred compound of Formula III is 4-[4-(3-[ 8F]fluoropropyl)benzyl]glutami acid:
Figure imgf000031_0001
Another preferred compound of Formula III is 4-{4-[(3-[18F]fluoropropyl)amino]benzyl}-
Figure imgf000031_0002
Another preferred compound of Formula III is 4-{4-[(3-[ 8F]fluorocyclobutyl)oxy]b!
Figure imgf000031_0003
Another preferred compound of Formula III is 4-{3-[4-(2-[18F]fluoroethoxy)phenyl]-
Figure imgf000031_0004
Another preferred compound of Formula III is 2-amino-5-[4-(2-[ 8F]fluoroethoxy)-
Figure imgf000031_0005
A more preferred compound of Formula III is 4-[4-(2-[18F]fluoroeihoxy)b!
glutamic acid:
Figure imgf000032_0001
Another more preferred compound of Formula III is 4-[4-(3-[18F]fluoropropoxy)benzyl]-L-
Figure imgf000032_0002
Another more preferred compound of Formula III is 4-[4-(3-[ 8F]fluoropropyl)benzyl]-L-
Figure imgf000032_0003
Another more preferred compound of Formula III is 4-{4-[(3-[ 8F]fluoropropyl)-
Figure imgf000032_0004
Another more preferred compound of Formula III is 4-{4-[(cis-3-[18F]fluorocyclobutyl)-
Figure imgf000032_0005
Another more preferred compound of Formula III is (4S)-4-{3-[4-(2-[18F]fluoroethoxy)- phenyl]propyl}-L-glutamic acid:
Figure imgf000033_0001
Another more preferred compound of Formula III is (2S)-2-amino-5-[4-(2-[18F]fluoro-
Figure imgf000033_0002
Another more preferred compound of Formula III is (2R)-2-amino-5-[4-(2-[ 8F]fluoro-
Figure imgf000033_0003
Another more preferred compound of Formula III is (4-{[5-(2-[ 8F]fluoroethoxy)pyridin-2- yl]methyl}-L-glutamic acid:
Figure imgf000033_0004
Another more preferred compound of Formula III is (2S)-2-Amino-5-{[5-(2- 8F]fluoroethoxy)pyridin-2-yl]methyl}hexanedioic acid:
Figure imgf000033_0005
Another more preferred compound of Formula III is 4-{[5-(2-[18F]fluoroethoxy)-1 - oxidopyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000034_0001
Another more preferred compound of Formula III is (2S)-2-amino-5-{2-[4-(2- [18F]fluoroethoxy)phenyl]ethyl}hexanedioic acid:
Figure imgf000034_0002
Another more preferred compound of Formula III is (2S)-2-amino-5-[4- 8F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000034_0003
Another more preferred compound of Formula III is (2 S, 5R)-2-a m i no-5-[4- 8F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000034_0004
Another more preferred compound of Formula III is (2S,5S)-2-amino-5-[4- 8F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000034_0005
Another more preferred compound of Formula III is 4-[4-(2-[18F]fluoroethoxy)-3-
Figure imgf000035_0001
Another more preferred compound of Formula III is (4S)-4-{4- [( 8F)fluoromethoxy]benzyl}-L-glutamic acid:
Figure imgf000035_0002
Another more preferred compound of Formula III is (4R)-4-{4- [(18F)fluoromethoxy]benzyl}-L-glutamic acid:
Figure imgf000035_0003
Another more preferred compound of Formula III is (2S)-2-amino-5-(4-{[2- 18F)fluoroethyl]amino}benzyl)hexanedioic acid:
Figure imgf000035_0004
Another more preferred compound of Formula III is (2S)-2-amino-5-(4-{[(2S,3R)-4- (18F)fluoro-2,3-dihydroxybutyl]oxy}benzyl)hexanedioic acid:
Figure imgf000036_0001
Another more preferred compound of Formula III is 4-({6-[2-(18F)fluoroethoxy]pyridin-3- yl}methyl)-L-glutamic acid:
Figure imgf000036_0002
Another more preferred compound of Formula III is 4-(4-{[(2S,3R)-4-(18F)fluoro-2,3- dihydroxybutyl]oxy}benzyl)-L-glutamic acid:
Figure imgf000036_0003
Another more preferred compound of Formula III is 4-(4-{[1-(18F)fluoro-3- hydroxypropan-2-yl]oxy}benzyl)-L-glutamic acid:
Figure imgf000036_0004
Another more preferred compound of Formula III is 4-({1-[2-(18F)fluoroethyl]-1 H-1 ,2,3- triazol-4-yl}methyl)-L-glutamic acid:
Figure imgf000037_0001
Another more preferred compound of Formula III is (2S,5R)-2-amino-5-[4- 8F]fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000037_0002
Another more preferred compound of Formula III is (2S.5S)-2-amino-5-[4- 8F]fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000037_0003
The third aspect of th compounds of Formula II:
Figure imgf000037_0004
wherein, R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
wherein at least one of R1, R2, R3 and R4 is not hydrogen,
X is selected from the group comprising:
a) CH2,
Figure imgf000038_0001
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*.
c) alkylene-N*H.
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula II:
Figure imgf000039_0001
wherein,
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group, wherein at least one of R1, R2, R3 and R4 is not hydrogen, X is selected from the group comprising:
a) CH2,
Figure imgf000039_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*.
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene, h) (R6-0),(R7-0)-disubstituted alkylene-O*, and i) (CH2CH20),-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
Rs is
a) hydrogen or
b) hydroxyl protecting group,
R6 is
a) hydrogen or
b) hydroxyl protecting group,
R7 is
a) hydrogen or b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula II:
Figure imgf000040_0001
II
wherein,
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
wherein at least one of R1, R2, R3 and R4 is not hydrogen,
X is selected from the group comprising:
a) CH2, and
Figure imgf000040_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
>) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxyl protecting group,
R6 is a) hydrogen or
b) hydroxy! protecting group,
R7 i I:S
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
Preferred features of invention and embodiments thereof:
Preferably, R1 is a carboxyl-protecting group.
The carboxyl-protecting group is preferably selected from methyl, ethyl, propyl, butyl, ferf-butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R1 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) ferf-butyl.
Even more preferably, R1 is ferf-butyl.
Preferably, R1 is selected from the group comprising:
hydrogen, methyl, ethyl, propyl, butyl, ferf-butyl, allyl, benzyl, 4-methoxybenzyl and 4- methoxyphenyl.
More referably, R1 is selected from the group comprising:
a) hydrogen,
b) methyl,
c) ethyl, and
d) ferf-butyl.
Preferably, R2 is a carboxyl-protecting group.
The carboxyl-protecting group is preferably selected from methyl, ethyl, propyl, butyl, ferf-butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R2 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) ferf-butyl.
Even more preferably, R2 is ferf-butyl. Preferably, R2 is selected from the group comprising:
hydrogen, methyl, ethyl, propyl, butyl, ferf-butyl, allyl, benzyl, 4-methoxybenzyl and 4- methoxyphenyl.
More referably, R2 is selected from the group comprising:
a) hydrogen,
b) methyl,
c) ethyl, and
d) fert-butyl. Preferably, R1 and R2 are both a carboxyl protecting group. Preferably, R3 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), fert-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R3 is selected from the group comprising:
a) hydrogen,
b) iert-butyloxycarbonyl (Boc), and
c) triphenylmethyl (Trityl).
More preferably R3 is selected from the group comprising:
a) fert-butyloxycarbonyl (Boc), and
b) triphenylmethyl (Trityl). Preferably, R4 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), fert-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R4 is selected from the group comprising:
a) hydrogen,
b) ferf-butyloxycarbonyl (Boc), and
c) triphenylmethyl (Trityl).
More preferably R4 is selected from the group comprising:
a) /ert-butyloxycarbonyl (Boc) and
b) triphenylmethyl (Trityl). Additionally, R3 and R4 optionally form an amine-protecting group, resulting
being 1 ,3-dioxo-1 ,3-dihydro-2H-isoindol-2-yl (phthalimido) or an azido grou
Preferably, R3 is hydrogen and R4 is an amine protecting group.
More preferably, R3 is hydrogen and R4 is ferf-Butyloxycarbonyl (Boc).
More preferably, R3 is hydrogen and R4 is triphenylmethyl (Trityl).
Preferably, R3 and R4 are never Hydrogen at the same time.
Preferably, R1 and R2 are both a carboxyl protecting group, R3 is hydrogen and R4 is an amine protecting group.
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2.
Preferably, A is Ci-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene.
Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl Q is a pyridylene as defined below
Figure imgf000043_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to L.
Preferably, L is selected from the group comprising:
a) C2-C6 alkylene,
b) C2-C6 alkylene-0*, c) C2-C6 alkylene-N*H.
d) C3-C6 cycloalkylene-O*.
e) (R5-0)-substituted C2-C6 alkylene,
f) (R5-0)-substituted C3-C6 alkylene-O*,
g) (R6-0),(R7-0)-disubstituted C3-C6 alkylene,
h) (R6-0).(R7-0}-disubstituted C4-C6 alkylene-O* , and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3.
indicates the position of the bond to Q.
More preferably, L is selected from the group comprising:
a) propylene,
b) propylene-O*,
c) ethylene-O*,
d) propylene-N*H,
e) cyclobutylene-O*,
Figure imgf000044_0001
* indicates the position of the bond to Q and * indicates the position of the bond to 18F.
If L is alkylene, L is preferably linear or branched C2-Ce alkylene. More preferably, L is C2-C:J alkylene selected from ethylene and propylene.
Preferably, L is propylene. Preferably, L is ethylene.
Preferably, L is methylene.
If L is alkylene-O* L is preferably Ci alkylene-O* (methylene-O*) or linear or branched C2-C6 alkylene-O*. More preferably, L is C2-C3 alkylene-O* is selected from ethylene-O* and propylene-O*.
Preferably, L is propylene-O*.
Preferably, L is ethylene-O*.
Preferably, L is methylene-O*.
If L is alkylene-N*H L is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L is C2-C3 alkylene-N*H, selected from ethylene-N*H and propylene-N*H.
Preferably, L is propylene-N*H.
Preferably, L is ethylene-N*H.
Preferably, L is methylene-N*H.
"Aikylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, aikylene is Ci aikylene or C2-C6 aikylene. More preferably, aikylene is C2-C3 aikylene or C.-Ce aikylene.
The same applies to C2-C6 alkylene-O* and C2-Ce alkylene-NH*.
"Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L is cycloalkylene-O* L is preferably C3-C6 cycloalkylene-O* such as cyclopropylene- O*, cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
is
Figure imgf000045_0001
indicates the position of the bond to 18F. If L is (R5-0)-substituted C2-C6 alkylene, (R5-0)-substituted C3-C6 alkylene-O*, (R6- 0),(R7-0)-disubstituted C3-C6 alkylene, or (R6-0).(R7-0)-disubstituted C.5-C6 alkylene-O*, L is preferably an alkylene defined as above bearing one or two protected or unprotected hydroxy I groups.
Preferably, L is (R5-0)-substituted Cs-Ce alkylene-O* selected from
Figure imgf000046_0001
Preferably, L i 6-0),(R7-0)-disubstituted Ci-C6 alkylene-O* selected from
Figure imgf000046_0002
* indicates the position of the bond to Q, * indicates the position of the bond to
Preferably, R5 is a hydroxyl protecting group.
Preferably, R6 and R7 are hydroxyl protecting groups.
Additionally, R6 and R7 optionally form together one-diol protecting group.
Compounds of Formula II are defined by the general formula and/or the combination of the preferred features as defined above.
In a first embodiment, compounds of the formula II are defined as compounds of Formula 11-1 , See structure in table C.
In a second embodiment, compounds of the formula II are defined as compounds of Formula II-2, See structure in table C.
In a third embodiment, compounds of the formula II are defined as compounds of Formula II-3, See structure in table C. In a fourth embodiment, compounds of the formula II are defined as compounds of Formula 11-4, See structure in table C. I n a fifth embodiment, compounds of the formula II are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula 11-1 , Formula II-2. Formula II-3 and Formula II- including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments. Table C: Formula II stereoisomers
Figure imgf000047_0001
II-3 II-4
The compounds of Formula 11-1 , Formula II-2, Formula II-3, Formula II-4 furthermore encompass pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, and solvates thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipients.
A preferred compound of Formula II is di-fert-butyl A/-(fert-butoxycarbonyl)-4-[4-(2- [,8F]fluoroethoxy)benzyl]glutamate:
Figure imgf000048_0001
Another preferred compound of Formula II is di-fert-butyl V-(ferf-butoxycarbonyl)-4-[4- 18F]fluoropropoxy)benzyl]glutamate:
Figure imgf000048_0002
Another preferred compound of Formula II is di-fert-butyl N-(ferf-butoxycarbonyl)-4-[4- 8F]fluoropropyl)benzyl]glutamate:
Figure imgf000048_0003
Another preferred compound of Formula II is di-ferf-butyl /V-(fert-butoxycarbonyl)-4-(4- 8F]fluoropropyl]amino}benzyl)glutamate:
Figure imgf000048_0004
Another preferred compound of Formula II is di-ferf-butyl A/-(fert-butoxycarbonyl)-4-(4- 18F]fluorocyclobutyl]oxy}benzyl)glutamate:
Figure imgf000048_0005
Another preferred compound of Formula II is di-fert-butyl V-(ferf-butoxycarbonyl)-4-{3- 18FJfluoroethoxy)phenyl]propyl}glutamate:
Figure imgf000049_0001
Another preferred compound of Formula II is di-iert-butyl 2-[(ferf-butoxycarbonyl)amino]- 18F]fluoroethoxy)benzyl]hexanedioate:
Figure imgf000049_0002
A more preferred compound of Formula II is di-iert-butyl /V-(tenf-butoxycarbonyl)-4-[4-(2- 8F]fluoroethoxy)benzyl]-L-glutamate:
Figure imgf000049_0003
Another more preferred compound of Formula II is di-ferf-butyl /V-(ferf-butoxycarbonyl)- 18F]fluoropropoxy)benzyl]-L-glutamate:
Figure imgf000049_0004
Another more preferred compound of Formula II is di-ferf-butyl W-(fert-butoxycarbonyl)- 4-[4-(3-[ 8F]fluoropropyl)benzyl]-L-glutamate:
Figure imgf000050_0001
Another more preferred compound of Formula II is di-fert-butyl N-(tert-butoxycarbonyl)- 18F]fluoropropyl]amino}benzyl)-L-glutamate:
Figure imgf000050_0002
Another more preferred compound of Formula II is di-fert-butyl /V-(fert-butoxycarbonyl)- 18F]fluorocyclobutyl]oxy}benzyl)-L-glutamate:
Figure imgf000050_0003
Another more preferred compound of Formula II is di-fert-butyl (4S)-N-(tert- 18F]fluoroethoxy)phenyl]propyl}-L-glutamate:
Figure imgf000050_0004
Another more preferred compound of Formula II is di-fert-butyl (2S)-2-[(ferf- butoxycarbonyl)amino]-5-[4-(2-[18F]fluoroethoxy)benzyl]hexanedioate:
Figure imgf000051_0001
Another more preferred compound of Formula II is di-iert-butyl (2R)-2-[(fert-butoxy- 8F]fluoroethoxy)benzyl]hexanedioate:
Figure imgf000051_0002
Another more preferred compound of Formula II is di-tert-butyl N-(fert-butoxycarbonyl)- 4-({5-[2-(18F)fluoroethoxy]pyridin-2-yl}methyl)-L-glutamate:
Figure imgf000051_0003
Another more preferred compound of Formula II is di-tert-butyl (2S)-2-[(fert- butoxycarbonyl)amino]-5-{[5-(2-[ 8F]fluoroethoxy)pyridin-2-yl]methyl}hexanedioate:
Figure imgf000051_0004
Another more preferred compound of Formula II is di-fert-Butyl N-(tert-butoxycarbonyl)- 4-{[5-(2-[,8F]fluoroethoxy)-1 -oxidopyridin-2-yl]methyl}-L-glutamate:
Figure imgf000052_0001
Another more preferred compound of Formula II is (2S)-2-fert-butoxycarbonylamino-5- 8F]fluoro-ethoxy)-phenyl]-ethyl}-hexanedioic acid di-ferf-butyl ester:
Figure imgf000052_0002
Another more preferred compound of Formula II is di-fert-butyl-N-(fert-butoxycarbonyl)- 4-[3-iert-butoxy-4-(2-[18F]fluoroethoxy)benzyl]-L-glutamate:
Figure imgf000052_0003
Another more preferred compound of Formula II is di-ferf-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-(4-{(tert-butoxycarbonyl)[2- (18F)fluoroethyl]amino}benzyl)hexanedioate:
Figure imgf000053_0001
Another more preferred compound of Formula II is di-iert-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-[4-({(4S.5R)-5-[(18F)fluoromethyl]-2!2-dimethyl-1 ,3-dioxolan-4- yl}methoxy)benzyl]hexanedioate:
Figure imgf000053_0002
Another more preferred compound of Formula II is di-iert-butyl (4S)-N-(tert- butoxycarbonyl)-4-({6-[2-(18F)fluoroethoxy]pyridin-3-yl}methyl)-L-glutamate:
Figure imgf000053_0003
Another more preferred compound of Formula II is di-iert-butyl (4S)-N-(ferf- butoxycarbonyl)-4-[4-({(4S,5R)-5-[(18F)fluoromethyl]-2,2-dimethyl-1 ,3-dioxolan-4- yl}methoxy)benzyl]-L-glutamate: CH3 O
H 3,C CH,
Another more preferred compound of Formula II is di-iert-butyl (4S)-N-(terf- butoxycarbonyl)-4-(4-{[1-(18F)fluoro-3-hydroxypropan-2-yl]oxy}benzyl)-L-glutamate:
Figure imgf000054_0001
Another more preferred compound of Formula II is di-iert-butyl (4R)-N-(iert- butoxycarbonyl)-4-({1-[2-(18F)fluoroethyl]-1 H-1.2,3-triazol-4-yl}methyl)-L-glutamate:
Figure imgf000054_0002
Another more preferred compound of Formula II is di-ferf-butyl N-(ferf-butoxycarbonyl)- 4-{4-[(18F)fluoromethyl]benzyl}-L-glutamate:
Figure imgf000054_0003
The fourth aspect of the present invention is directed to compounds of Formula VI:
Figure imgf000055_0001
VI
wherein,
X is selected from the group comprising
a) CH2,
Figure imgf000055_0002
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-NTH,
d) cycloalkylene-O*,
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula VI:
Figure imgf000055_0003
wherein,
X is selected from the group comprising a) CH2,
Figure imgf000056_0001
A is alkylene,
Q is arylene or heteroarylene.
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O* ,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof. In a further embodiment, the invention is directed to compounds of Formula VI:
Figure imgf000056_0002
VI
wherein,
X is selected from the group comprising
a) CH2, and
Figure imgf000056_0003
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-NTH,
d) cycloalkylene-O*, e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
Preferred features of invention and embodiments thereof:
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2. Preferably, A is C-i-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene. Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl Q is a pyridylene as defined below
Figure imgf000057_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to L1.
Preferably, L is selected from the group comprising:
a) C2-C6 alkylene,
b) C2-C6 alkylene-0*,
c) C2-C6 alkylene-N*H,
d) C3-C6 cycloalkylene-O*,
e) monohydroxy C2-Ce alkylene, f) monohydroxy C3-Ce alkylene-O*,
g) dihydroxy Cs-Ce alkylene,
h) dihydroxy C4-C6 alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1
* indicates the position of the bond to Q.
More preferably, L1 is selected from the group comprising:
a) propylene,
b) propylene-O*,
c) ethylene-O*.
d) propylene-N*H,
e) cyclobutylene-O*,
Figure imgf000058_0001
indicates the position of the bond to Q and # indicates the position of the bond to F.
If L1 is alkylene, L1 is preferably linear or branched C2-Ce alkylene. More preferably, L1 is C2-C3 alkylene selected from ethylene and propylene.
Preferably, L1 is propylene.
Preferably, L is ethylene.
Preferably, L is methylene.
If L1 is alkylene-O* L1 is preferably Ci alkylene-O* (methylene-O*) or linear or branched C2-C6 alkylene-O*. More preferably, L1 is C2-C3 alkylene-O* is selected from ethylene- O* and propylene-O*.
Preferably, L1 is propylene-O*.
Preferably, L1 is ethylene-O*.
Preferably, L is methylene-O*. If L1 is alkylene-N*H L1 is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L1 is C2-C3 alkylene-ΝΉ, selected from ethylene-N*H and propylene-ΝΉ.
Preferably, L1 is propylene-N*H.
Preferably, L is ethylene-N*H.
Preferably, L is methylene-N*H.
"Alkylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, alkylene is Ci alkylene or C2-C6 alkylene. More preferably, alkylene is C2-C3 alkylene or C4-C6 alkylene.
The same applies to C2-C6 alkylene-O* and C2-C6 alkylene-NH*.
"Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L1 is cycloalkylene-O* L1 is preferably Ca-Ce cycloalkylene-O* such as cyclopropylene-O*. cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
1 is
Figure imgf000059_0001
* indicates the position of the bond to F.
If L1 is a monohydroxy C2-C6 alkylene, monohydroxy Cs-Ce alkylene-O*, dihydroxy C3-C6 alkylene, or dihydroxy Cj-Ce alkylene-O*, L1 is preferably an alkylene as defined above bearing one or two hydroxy I groups.
Preferably, L1 is monohydroxy Cs-Ce alkylene-O* selected from
Figure imgf000059_0002
Preferably; , L1 is dihydroxy Ci-Ce alkylene-O* selected from
Figure imgf000060_0001
* indicates the position of the bond to Q, # indicates the position of the bond to F.
Compounds of Formula VI are defined by the general formula and/or the combination of the preferred features as defined above.
In a first embodiment, compounds of the formula VI are defined as compounds of Formula VI-1 , See structure in table D.
In a second embodiment, compounds of the formula VI are defined as compounds of Formula VI -2, See structure in table D.
In a third embodiment, compounds of the formula VI are defined as compounds of Formula VI -3, See structure in table D.
In a fourth embodiment, compounds of the formula VI are defined as compounds of Formula VI-4. See structure in table D.
In a fifth embodiment, compounds of the formula VI are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula VI-1 , Formula VI -2, Formula VI -3 and Formula VI-4 including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments.
Table D: Formula VI stereoisomers
Figure imgf000060_0002
VI-1 VI-2
Figure imgf000061_0001
VI-3 VI-4
The compounds of Formula VI-1 , Formula VI-2, Formula VI-3, Formula VI-4 furthermore encompass pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, solvates and prodrugs thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipients.
The compounds of Formula VI may exist as zwitterions. All forms of the compounds, including free acid, free-base and zwitterions, are contemplated to be within the scope of the present invention. It is well known in the art that compounds containing both amino and carboxyl groups often exist in equilibrium with their zwitterionic forms. Thus, any of the compounds described herein throughout that contain, for example, both amino and carboxyl groups, also include reference to their corresponding zwitterions.
Figure imgf000061_0002
Another preferred compound of Formula VI is 4-[4-(3-fluoropropyl)benzyl]glutamic acid:
Figure imgf000062_0001
Figure imgf000062_0002
Another preferred compound of Formula VI is 4-(4-{[3-fluorocyclobutyl]oxy}benzyl)-
Figure imgf000062_0003
Another preferred compound of Formula VI is 4-(3-{4-[2-fluoroeihoxy]phenyl}propyl)- glutamic acid:
Figure imgf000062_0004
Another preferred compound of Formula VI is 4-{3-[4-(3- cid:
Figure imgf000062_0005
Another preferred compound of Formula VI is 2-amino-5-{4-[2-fluoroethoxy]benzyl}- hexanedioic acid:
Figure imgf000063_0001
Another preferred compound of Formula VI is 4-{[5-(3-Fluoropropyl)pyridin-2-yl]methyl}- glutamic acid:
Figure imgf000063_0002
A more preferred compound of Formula VI is (4S)-4-[4-(2-fluoroethoxy)bi
lutamic acid:
Figure imgf000063_0003
Another more preferred compound of Formula VI is (4R)-4-[4-(2-fluoroethoxy)benzyl]-D-
Figure imgf000063_0004
Another more preferred compound of Formula VI is (4S)-4-[4-(3-fluoropropoxy)b! L- lutamic acid:
Figure imgf000063_0005
Another more preferred compound of Formula VI is (4R)-4-[4-(3-fluoropropoxy)benzyl]- D-glutamic acid:
Figure imgf000064_0001
Another more preferred compound of Formula VI is 4-[4-(3-fluoropropyl)benzyl]-L-
Figure imgf000064_0002
Another more preferred compound of Formula VI is (4S)-4-(4-{[3-fluoropropyl].
Figure imgf000064_0003
Another more preferred compound of Formula VI is (4S)-(4-{[cis-3-fluorocyclobutylj-
Figure imgf000064_0004
Another more preferred compound of Formula VI is (4S)-4-(3-{4-[2-fluoroethoxy]-
Figure imgf000064_0005
Another more preferred compound of Formula VI is (4S)-4-(3-{4-[2-fluoropropyl]- phenyl}propyl)-L-glutamic acid:
Figure imgf000065_0001
Another more preferred compound of Formula VI is (2S)-2-amino-5-[4-(2-fluoroethoxy)-
Figure imgf000065_0002
Another more preferred compound of Formula VI is (2R)-2-amino-5-[4-(2-fluoroethoxy)-
Figure imgf000065_0003
Another more preferred compound of Formula VI is (4R)-4-{[5-(3-Fluoropropyl)pyridin-2- yl]methyl}-L-glutamic acid:
Figure imgf000065_0004
Another more preferred compound of Formula VI is (4R)-(4-{[5-(2-fluoroethoxy)pyridin- 2-yl]methyl}-L-glutamic acid:
Figure imgf000065_0005
Another more preferred compound of Formula VI is (2S)-2-Amino-5-{[5-(2- fluoroethoxy)pyridin-2-yl]methyl}hexanedioic acid:
Figure imgf000066_0001
Another more preferred compound of Formula VI is (4£?)-4-{[5-(2-fluoroethoxy)-1 - oxidopyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000066_0002
Another more preferred compound of Formula VI is (2S)-2-amino-5-{2-[4-(2- anedioic acid:
Figure imgf000066_0003
Another more preferred compound of Formula VI is (2S)-2-amino-5-[4- acid:
Figure imgf000066_0004
Another more preferred compound of Formula VI is (2S.5R)-2-amino-5-[4- (fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000066_0005
Another more preferred compound of Formula VI is (2S,5S)-2-amino-5-[4- acid:
Figure imgf000067_0001
Another more preferred compound of Formula VI is (4S)-4-[4-(2-fluoroethoxy)-3- hydroxybenzyl]-L-glutamic acid:
Figure imgf000067_0002
Another more preferred compound of Formula VI is (4S)-4-{4-[(fluoromethoxy]benzyl}-L- glutamic acid:
Figure imgf000067_0003
Another more preferred compound of Formula VI is (4R)-4-{4-[fluoromethoxy]benzyl}-L- glutamic acid:
Figure imgf000067_0004
Another more preferred compound of Formula VI is (2S)-2-amino-5-(4-{[2- acid:
Figure imgf000067_0005
Another more preferred compound of Formula VI is (2S)-2-amino-5-(4-{[(2S,3R)-4- fluoro-2.3-dihydroxybutyl]oxy}benzyl)hexanedioic acid:
Figure imgf000068_0001
Another more preferred compound of Formula VI is (4S)-4-({6-[2-fluoroethoxy]pyridin-3- yl}methyl)-L-glutamic acid:
Figure imgf000068_0002
Another more preferred compound of Formula VI is (4S)-4-(4-{[(2S,3R)-4-fluoro-2,3- dihydroxybutyl]oxy}benzyl)-L-glutamic acid:
Figure imgf000068_0003
Another more preferred compound of Formula VI is (4S)-4-(4-{[1 -fluoro-3- hydroxypropan-2-yl]oxy}benzyl)-L-glutamic acid:
Figure imgf000068_0004
Another more preferred compound of Formula VI is 4-({1 -[2-fluoroethyl]-1 H-1 ,2,3-triazol-
4-yl}methyl)-L-glutamic acid:
Figure imgf000069_0001
Another more preferred compound of Formula VI is (2S,5R)-2-amino-5-[4- :
Figure imgf000069_0002
Another more preferred compound of Formula VI is (2S.5S)-2-amino-5-[4- :
Figure imgf000069_0003
Another more preferred compound of Formula VI is (4S)-4-{4-fluoromethyl]benzyl}-L- glutamic acid:
Figure imgf000069_0004
The fifth aspect of th compounds of Formula V:
Figure imgf000069_0005
wherein, R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
wherein at least one of R1, R2, R3 and R4 is not hydrogen,
X is selected from the group comprising:
a) CH2,
Figure imgf000070_0001
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*.
c) alkylene-N*H.
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula V:
Figure imgf000071_0001
V
wherein.
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group, wherein at least one of R1, R2, R3 and R4 is not hydrogen, X is selected from the group comprising:
a) CH2,
Figure imgf000071_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) a!kylene-O*,
c) alkylene-N*H.
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene, h) (R6-0),(R7-0)-disubstituted alkylene-O*, and i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxyl protecting group,
R6 is
a) hydrogen or
b) hydroxyl protecting group,
R7 is a) hydrogen or
b) hydroxy I protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
In a further embodiment, the invention is directed to compounds of Formula V:
Figure imgf000072_0001
V
wherein,
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
wherein at least one of R\ R2, R3 and R* is not hydrogen,
X is selected from the group comprising:
a) CH2, and
Figure imgf000072_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H.
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0).(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or b) hydroxy! protecting group,
R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxy! protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
Preferred features of invention and embodiments thereof:
Preferably, R1 is a carboxyl-protecting group.
The carboxyl-protecting group is preferably selected from methyl, ethyl, propyl, butyl, fert-butyl, ally!, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R1 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) fert-butyl.
Even more preferably, R1 is fert-butyl.
Preferably, R1 is selected from the group comprising:
hydrogen, methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl and 4- methoxyphenyl.
More referably, R1 is selected from the group comprising:
a) hydrogen,
b) methyl,
c) ethyl, and
d) fert-butyl. Preferably, R2 is a carboxyl-protecting group.
The carboxyl-protecting group is preferably selected from methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R2 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) fert-butyl. Even more preferably, R2 is fert- butyl.
Preferably, R2 is selected from the group comprising:
hydrogen, methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl and 4- methoxyphenyl.
More referably, R2 is selected from the group comprising:
a) hydrogen,
b) methyl,
c) ethyl, and
d) tert-butyl.
Preferably, R1 and R2 are both a carboxyl protecting group.
Preferably, R3 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), fert-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl
(PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R3 is selected from the group comprising:
a) hydrogen,
b) /ert-butyloxycarbonyl (Boc), and
c) triphenylmethyl (Trityl).
More preferably R3 is selected from the group comprising:
a) ferf-butyloxycarbonyl (Boc), and
b) triphenylmethyl (Trityl).
Preferably, R4 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), fert-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R4 is selected from the group comprising:
a) hydrogen,
b) ierf-butyloxycarbonyl (Boc), and
c) triphenylmethyl (Trityl).
More preferably R4 is selected from the group comprising: a) fert-butyloxycarbonyl (Boc) and
b) triphenylmethyl (Trityl).
Additionally, R3 and R4 optionally form an amine-protecting group, resulting in NR3R4 being 1 ,3-dioxo-1 ,3-dihydro-2H-isoindol-2-yl (phthalimido) or an azido group.
Preferably, R3 is hydrogen and R4 is an amine protecting group.
More preferably, R3 is hydrogen and R4 is iert-Butyloxycarbonyl (Boc).
More preferably, R3 is hydrogen and R4 is triphenylmethyl (Trityl).
Preferably, R3 and R4 are never Hydrogen at the same time.
Preferably, R1 and R2 are both a carboxyl protecting group, R3 is hydrogen and R4 is an amine protecting group.
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2. Preferably, A is Ci-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene. Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl , Q is a pyridylene as defined below
Figure imgf000075_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to L.
Preferably, L is selected from the group comprising: a) C2-Ce alkylene.
b) C2-C6 alkylene-O*.
c) C2-C6 alkylene-N*H.
d) Ca-Ce cycloalkylene-O*.
e) (R5-0)-substituted C2-C6 alkylene,
f) (R5-0)-substituted C3-C6 alkylene-O*.
g) (R6-0),(R7-0)-disubstituted C3-C6 alkylene.
h) (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O* , and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3.
* indicates the position of the bond to Q
More preferably, L is selected from the group comprising:
a) propylene,
b) propylene-O*,
c) ethylene-O*,
d) propylene-N*H,
e) cyclobutylene-O*,
d
Figure imgf000076_0001
indicates the position of the bond to Q and * indicates the position of the bond to F.
If L is alkylene, L is preferably linear or branched C2-C6 alkylene. More preferably, L is C2-C3 alkylene selected from ethylene and propylene. Preferably, L is propylene.
Preferably, L is ethylene.
Preferably, L is methylene. If L is alkylene-O* L is preferably Ci alkylene-O* (methylene-O*) or linear or branched C2-C6 alkylene-O*. More preferably, L is C2-C3 alkylene-O* is selected from ethylene-O* and propylene-O*.
Preferably, L is propylene-O*.
Preferably, L is ethylene-O*.
Preferably, L is methylene-O*.
If L is alkylene-N*H L is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L is C2-C3 alkylene-N*H, selected from ethylene-N*H and propylene-N*H.
Preferably, L is propylene-N*H.
Preferably, L is ethylene-N*H.
Preferably, L is methylene-N*H.
"Alkylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, alkylene is Ci alkylene or C2-C6 alkylene. More preferably, alkylene is C2-C3 alkylene or C4-C6 alkylene.
The same applies to C2-C6 alkylene-O* and C2-Ce alkylene-NH*. "Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L is cycloalkylene-O* L is preferably Cs-Ce cycloalkylene-O* such as cyclopropylene- O*, cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
is
Figure imgf000077_0001
* indicates the position of the bond to F. If L is (R5-0)-substituted C2-C6 alkylene, (R5-0)-substituted C3-C6 alkylene-O*, (R6- 0),(R7-0)-disubstituted C3-C6 alkylene, or (R6-0).(R7-0)-disubstituted C.5-C6 alkylene-O*, L is preferably an alkylene defined as above bearing one or two protected or unprotected hydroxy I groups.
Preferably, L is (R5-0)-substituted Cs-Ce alkylene-O* selected from
Figure imgf000078_0001
Preferably, L i 6-0).(R7-0)-disubstituted C4-C6 alkylene-O* selected from
Figure imgf000078_0002
* indicates the position of the bond to Q, * indicates the position of the bond to F.
Preferably, R5 is a hydroxyl protecting group.
Preferably, R6 and R7 are hydroxyl protecting groups.
Additionally, R6 and R7 optionally form together one-diol protecting group.
Compounds of Formula V are defined by the general formula and/or the combination of the preferred features as defined above.
In a first embodiment, compounds of the formula V are defined as compounds of Formula V-1 , See structure in table E.
In a second embodiment, compounds of the formula V are defined as compounds of Formula V-2, See structure in table E.
In a third embodiment, compounds of the formula V are defined as compounds of Formula V-3, See structure in table E. In a fourth embodiment, compounds of the formula V are defined as compounds of Formula V-4, See structure in table E. In a fifth embodiment, compounds of the formula V are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula V-1 , Formula V-2, Formula V-3 and Formula V-4 including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments. Table E: Formula V stereoisomers
Figure imgf000079_0001
V-3 V-4
A preferred compound of Formula V is di-ferf-butyl /V-(fert-butoxycarbonyl)-4-{4-[2-
Figure imgf000079_0002
Another preferred compound of Formula V is di-ferf-butyl A/-(fert-butoxycarbonyl)-4-{4- [3-fluoropropoxy]benzyl}glutamate:
Figure imgf000080_0001
Another preferred compound of Formula V is di-fert-butyl V-(fe/t-butoxycarbonyl)-4-{4-
Figure imgf000080_0002
Another preferred compound of Formula V is di-fert-butyl W-(fert-butoxycarbonyl)-4-(4-
Figure imgf000080_0003
Another preferred compound of Formula V is di-fert-butyl /V-(fert-butoxycarbonyl)-4-(4- te:
Figure imgf000080_0004
Another preferred compound of Formula V is di-iert-butyl /V-(iert-butoxycarbonyl)-4-(3- :
Figure imgf000080_0005
Another preferred compound of Formula V is di-fert-butyl /V-(fert-butoxycarbonyl)-4-(3-
Figure imgf000081_0001
Another preferred compound of Formula V is di-fert-butyl 2-[(tert- benzyl}hexanedioate:
Figure imgf000081_0002
Another preferred compound of Formula V is di-iert-butyl /V-(fert-butoxycarbonyl)-4-{[5- (2-fluoroethoxy)pyridin-2-yl]methyl}glutamate:
Figure imgf000081_0003
Another preferred compound of Formula V is di-ferf-butyl A/-(fert-butoxycarbonyl)-4-{[5- (3-fluoropropyl)pyridin-2-yl]methyl}-glutamate:
Figure imgf000081_0004
A more preferred compound of Formula V is di-ferf-butyl (4S)-/V-(fert-butoxycarbonyl)-4- [4-(2-fluoroethoxy)benzyl]-L-glutamate:
Figure imgf000082_0001
Another more preferred compound of Formula V is di-fert-butyl (4R)-N-(tert- nzyl]-D-glutamate:
Figure imgf000082_0002
Another more preferred compound of Formula V is di-ferf-butyl (4S)-N-(tert- butoxycarbonyl)-4-{4-[3-fluoropropoxy]benzyl}-L-glutamate:
Figure imgf000082_0003
Another more preferred compound of Formula V is di-fert-butyl (4R)-/V-(fert-butoxy- -glutamate:
Figure imgf000082_0004
Another more preferred compound of Formula V is di-ferf-butyl /V-(fert-butoxycarbonyl)- :
Figure imgf000082_0005
Another more preferred compound of Formula V is di-fert-butyl (4S)-/V-(fert-butoxy- zyl)-L-glutamate:
Figure imgf000083_0001
Another more preferred compound of Formula V is di-fert-butyl (4S)-/V-(fert-butoxy(4S)- xy}benzyl)-L-glutamate:
Figure imgf000083_0002
Another more preferred compound of Formula V is di-fert-butyl (4S)-N-(tert- enyl}propyl)-L-glutamate:
Figure imgf000083_0003
Another more preferred compound of Formula V is di-fert-butyl (2S)-2-[(ferf- benzyl}hexanedioate:
Figure imgf000083_0004
Another more preferred compound of Formula V is di-fert-butyl (2R)-2-[(fert-butoxy- carbonyl)amino]-5-{4-[2-fluoroethoxy]benzyl}hexanedioate:
Figure imgf000084_0001
Another more preferred compound of Formula V is di-fert-butyl (4f?)- V-(ferf-butoxy- carbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}-L-glutamate:
Figure imgf000084_0002
Another more preferred compound of Formula V is di-fert-butyl (4R)-N-(tert- butoxycarbonyl)-4-{[5-(3-fluoropropyl)pyridin-2-yl]methyl}-L-glutamate:
Figure imgf000084_0003
Another more preferred compound of Formula V is di-tert-butyl (4R)-N-(tert- butoxycarbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}-L-glutamate:
Figure imgf000084_0004
Another more preferred compound of Formula V is di-ferf-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}hexanedioate:
Figure imgf000085_0001
Another more preferred compound of Formula V is di-ferf-buty (4R)
oxidopyridin-2-yl]methyl}-L-glutamate:
Figure imgf000085_0002
Another more preferred compound of Formula V is (2S)-2-fert-butoxycarbonylamino-5- hyl}-hexanedioic acid di-fert-butyl ester:
Figure imgf000085_0003
Another more preferred compound of Formula V is di-fert-butyl (4S)-N-(ferf- butoxycarbonyl)-4-[3-fert-butoxy-4-(2-fluoroethoxy)benzyl]-L-glutamate:
Figure imgf000086_0001
Another more preferred compound of Formula V is di-fert-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-(4-{(iert-butoxycarbonyl)[2-
Figure imgf000086_0002
Another more preferred compound of Formula V is di-iert-butyl (2S)-2-[(fert- butoxycarbonyl)amino]-5-[4-({(4S,5R)-5-[fluoromethyl]-2,2-dimethyl-1 ,3-dioxolan-4- yl}methoxy)benzyl]hexanedioate:
Figure imgf000086_0003
Another more preferred compound of Formula V is di-fert-butyl (4S)-N-(ferf- butoxycarbonyl)-4-({6-[2-fluoroethoxy]pyridin-3-yl}methyl)-L-glutamate:
Figure imgf000087_0001
Another more preferred compound of Formula V is di-iert-butyl (4S)-N-(iert- butoxycarbonyl)-4-[4-({(4S!5R)-5-[fluoromethyl]-2.2-dimethyl-1 !3-dioxolan-4- yl}methoxy)benzyl]-L-glutamate:
Figure imgf000087_0002
Another more preferred compound of Formula V is di-ferf-butyl (4S)-N-(ferf- butoxycarbonyl)-4-(4-{[1 -fluoro-3-hydroxypropan-2-yl]oxy}benzyl)-L-glutamate:
Figure imgf000087_0003
Another more preferred compound of Formula V is di-iert-butyl (AR)-N-(tert- butoxycarbonyl)-4-({1 -[2-fluoroethyl]-1 H-1 ,2.3-triazol-4-yl}methyl)-L-glutamate:
Figure imgf000087_0004
Another more preferred compound of Formula V is di-tert-butyl (4S)-N-(ferf- butoxycarbonyl)-4-[4-(fluoromethyl)benzyl]-L-glutamate:
Figure imgf000088_0001
The sixth aspect of th to compounds of Formula IV:
Figure imgf000088_0002
IV
wherein
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2,
Figure imgf000088_0003
A is alkylene,
Q is arylene or heteroarylene,
Z is selected from the group comprising:
a) HO-L*,
b) OH,
c) Halogen, and
d) NH2,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-NPH,
d) cycloalkylene-O*, e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0}-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 i I:S
a) hydrogen or
b) hydroxyl protecting group,
R7 i i!s
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof,
with the provisos, that:
Z is not Halogen if X is CH2,
Z is not OH if X is CH2, and Q is phenyl or
Z is not Halogen if X is CH2-CH2.
In a further embodiment, the invention is directed to compounds of Formula IV:
Figure imgf000089_0001
IV
wherein
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2,
b) CH2-CH2, and
Figure imgf000090_0001
A is aikylene,
Q is arylene or heteroarylene,
Z is selected from the group comprising:
a) HO-L*,
b) OH,
c) Halogen, and
d) NH2.
L is selected from the group comprising:
a) aikylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalky!ene-O*,
e) (R5-0)-substituted aikylene,
f) (R5-0)-substituted alkylene-O* ,
g) (R6-0),(R7-0)-disubstituted aikylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
') (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a. hydrogen or
b. hydroxyl protecting group,
R7 is
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof,
with the provisos, that:
Z is not Halogen if X is CH2,
Z is not OH if X is CH2, and Q is phenyl or
Z is not Halogen if X is CH2-CH2.
In a further embodiment, the invention is directed to compounds of Formula IV:
Figure imgf000091_0001
IV
wherein
R1 is hydrogen or a carboxyl protecting group, R2 is hydrogen or a carboxyl protecting group, R3 is hydrogen or an amine protecting group, R4 is hydrogen or an amine protecting group, X is selected from the group comprising:
a) CH2, and
Figure imgf000091_0002
A is alkylene,
Q is arylene or heteroarylene,
Z is selected from the group comprising:
a) HO-L*,
b) OH,
c) Halogen, and
d) NH2.
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*, g) (R6-0),(R7-0)-disubstituted alkylene, h) (Rs-0),(R7-0)-disubstituted alkylene-O*, and i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxyl protecting group,
R6 is
a. hydrogen or b. hydroxyl protecting group,
R7 is
a) hydrogen or
b) hydroxyl protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof,
with the provisos, that:
Z is not Halogen if X is CH2,
Z is not OH if X is CH2, and Q is phenyl or
Z is not Halogen if X is CH2-CH2.
In a further embodiment, the invention is directed to compounds of Formula IV:
Figure imgf000092_0001
wherein
R1 is hydrogen or a carboxyl protecting grou
R2 is hydrogen or a carboxyl protecting grou
R3 is hydrogen or an amine protecting group
R* is hydrogen or an amine protecting group
X is selected from the group comprising:
a) CH2,
Figure imgf000092_0002
A is alkylene,
Q is arylene or heteroarylene,
Z is selected from the group comprising:
a) HO-L*,
b) OH,
c) Halogen, and
d) NH2,
L is selected from the group comprising:
a) alkylene, b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*.
g) (R6-0),(R7-0)-disubstituted alkylene.
h) (R6-0).(R7-0)-disubstituted alkylene-O*. and
i) (CH2CH20)p-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group.
R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxy I protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof,
Preferred features of invention and embodiments thereof:
Preferably, R1 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R1 is selected from the group comprising:
a) methyl,
b) ethyl, and
c) fert-butyl.
Even more preferably, R1 is fert-butyl.
Preferably, R1 is hydrogen.
Preferably, R2 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl.
More preferably, R2 is selected from the group comprising:
a) methyl,
b) ethyl, and c) ferf-butyl.
Even more preferably, R2 is ferf-butyl.
Preferably, R2 is hydrogen. Preferably, R1 and R2 are identical.
Preferably, R3 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), terf-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenyimethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R3 is selected from the group comprising:
a) Hydrogen,
b) ferf-Butyloxycarbonyl (Boc), and
c) triphenyimethyl (Trityl).
More preferably R3 is selected from the group comprising:
a) ferf-butyloxycarbonyl (Boc), and
b) triphenyimethyl (Trityl). Preferably, R4 is hydrogen or an amine-protecting group.
The amine-protecting group is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), terf-butyloxycarbonyl (Boc), benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenyimethyl (Trityl) or methoxyphenyl diphenylmethyl (MMT).
Preferably R4 is selected from the group comprising:
a) Hydrogen,
b) ferf-Butyloxycarbonyl (Boc), and
c) triphenyimethyl (Trityl).
More preferably R4 is selected from the group comprising:
a) feri-butyloxycarbonyl (Boc) and
b) triphenyimethyl (Trityl).
Additionally, R3 and R4 optionally form an amine-protecting group, resulting in NR3R4 being 1 .3-dioxo-1 ,3-dihydro-2H-isoindol-2-yl (phthalimido) or an azido group.
Preferably, R3 is hydrogen and R4 is an amine protecting group. More preferably, R3 is hydrogen and R4 is fert-Butyloxycarbonyl (Boc).
More preferably, R3 is hydrogen and R4 is triphenylmethyl (Trityl).
Preferably, R3 and R4 are never Hydrogen at the same time.
Preferably, R1 and R2 are both a carboxyi protecting group, R3 is hydrogen and R4 is an amine protecting group.
In another preferred embodiment, R1, R2, R3 and R4 are hydrogen.
Preferably, X is CH2 or CH2-CH2.
More preferably, X is CH2.
More preferably, X is CH2-CH2. Preferably, A is Ci-Ce alkylene. More preferably, A is C1-C3 alkylene.
Even more preferably, A is methylene.
Even more preferably, A is ethylene.
Even more preferably, A is propylene. Preferably, Q is phenylene, triazolylene or pyridylene.
Preferably, Q is phenylene or pyridylene.
More preferably, Q is phenylene.
More preferably, Q is pyridylene or triazolylene.
More preferably, Q is pyridylene.
Even more preferabl Q is a pyridylene as defined below
Figure imgf000095_0001
1* indicates the position of the bond to A and 2* indicates the position of the bond to Z.
Preferably, Z is selected from the group comprising:
a) ΗΟ-Ι
b) OH,
c) NH2.
* indicates the position of the bond to Q. More preferably, Z is selected from the group comprising: a) HO-(C2-C3 alkylene),
b) HO-(C2-C3 alkylene)-0* ,
c) OH, and
d) NH2.
More preferably, Z is selected from the group comprising: a) HO-propylene-O* or OH-ethylene-O*.
b) HO-propylene,
c) OH, and
d) NH2,
with the proviso, that:
Z is not OH if X is CH2.
Preferably, Z is OH and X = CH2-CH2.
Preferably, L is selected from the group comprising:
a) C2-Ce alkylene,
b) C2-C6 alkylene-0*,
c) C2-C6 alkylene-N*H,
d) C3-C6 cycloalkylene-O*,
e) (R5-0)-substituted C2-C6 alkylene,
f) (R5-0)-substituted C3-C6 alkylene-0*, g) (R6-0),(R7-0)-disubstituted C3-C6 alkylene, h) (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O*. and i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3.
* indicates the position of the bond to Q
More preferably, L is selected from the group comprising: a) propylene,
b) propylene-O*,
c) ethylene-O*,
d) propylene-N*H,
e) cyclobutylene-O*,
d
Figure imgf000097_0001
indicates the position of the bond to Q and * indicates the position of the bond to OH.
If L is alkylene, L is preferably linear or branched C2-C6 alkylene. More preferably, L is C2-C3 alkylene selected from ethylene and propylene.
Preferably, L is propylene.
Preferably, L is ethylene.
Preferably, L is methylene.
If L is alkylene-O* L is preferably Ci alkylene-O* (methylene-O*) or linear or branched C2-C6 alkylene-O*. More preferably. L is C2-C3 alkylene-O* is selected from ethylene-O* and propylene-O*.
Preferably, L is propylene-O*.
Preferably, L is ethylene-O*.
Preferably, L is methylene-O*.
If L is alkylene-N*H L is preferably Ci alkylene-N*H or linear or branched C2-C6 alkylene-N*H. More preferably, L is C2-C3 alkylene-N*H, selected from ethylene-N*H and propylene-N*H.
Preferably, L is propylene-N*H.
Preferably, L is ethylene-N*H. Preferably, L is methylene-N*H.
"Aikylene" represents a linear or branched saturated bivalent chain of carbon atoms having 1 to 6, preferably 1 to 3 or 4 to 6, carbon atoms, by way of example and by preference methylene, ethylene and propylene. Preferably, aikylene is Ci aikylene or C2-C6 aikylene. More preferably, aikylene is C2-C3 aikylene or C4-C6 aikylene.
The same applies to C2-C6 alkylene-O* and C2-Ce alkylene-NH*.
"Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 4 to 6, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
If L is cycloalkylene-O* L is preferably Cs-Ce cycloalkylene-O* such as cyclopropylene- O*, cyclobutylene-O*, cyclopentylene-O* or cyclohexylene-O*.
is
Figure imgf000098_0001
* indicates the position of the bond to OH.
If L is (R5-0)-substituted C2-C6 aikylene, (R5-0)-substituted C3-C6 alkylene-O*, (R6- 0),(R7-0)-disubstituted C3-C6 aikylene, or (R6-0),(R7-0)-disubstituted C4-C6 alkylene-O*, L is preferably an aikylene defined as above bearing one or two protected or unprotected hydroxy I groups.
Preferably, L is 5-0)-substituted C3-C6 alkylene-O* selected from
Figure imgf000098_0002
Preferably, L is (R6-0),(R7- -0)-disubstituted C4-C6 alkylene-O* selected from
Figure imgf000099_0001
* indicates the position of the bond to Q, * indicates the position of the bond to OH.
Preferably. R5 is a hydroxyl protecting group.
Preferably. R6 and R7 are hydroxyl protecting groups.
Additionally, R6 and R7 optionally form together optionally one-diol protecting group.
Compounds of Formula IV are defined by the general formula and/or the combination the preferred features as defined above.
In a first embodiment, compounds of the formula IV are defined as compounds of Formula IV-1 , See structure in table F.
In a second embodiment, compounds of the formula IV are defined as compounds of Formula IV-2, See structure in table F.
In a third embodiment, compounds of the formula IV are defined as compounds of Formula IV-3, See structure in table F. In a fourth embodiment, compounds of the formula IV are defined as compounds of Formula IV-4, See structure in table F.
In a fifth embodiment, compounds of the formula IV are defined as encompassing single isomers or any mixture of at least two stereoisomers of Formula IV-1 , Formula IV-2, Formula IV-3 and Formula IV-4 including racemates and diastereomeric mixtures.
Preferred features as disclosed above are incorporated herein for all embodiments.
Table F: Formula IV stereoisomers
Figure imgf000100_0001
Figure imgf000100_0002
IV-3 IV-4
The compounds of Formula IV-1. Formula IV-2, Formula IV-3, Formula IV-4 furthermore encompass pharmaceutically acceptable salts of an inorganic or organic acid or base thereof, hydrates, complexes, esters, amides, and solvates thereof and optionally a pharmaceutically acceptable carrier, diluent, adjuvant or excipients.
A preferred compound of Formula IV is di-fert-butyl /V-(fert-butoxycarbony!)-4-(4-
Figure imgf000100_0003
Another preferred compound of Formula IV is di-fert-butyl 4-(4-aminobenzyl)-/V-(fert-
Figure imgf000100_0004
Another preferred compound of Formula IV is di-fert-butyl A/-(fert-butoxycarbonyl)-4-[4- (3-hydroxypropyl)benzyl]glutamate:
Figure imgf000101_0001
Another preferred compound of Formula IV is di-fert-butyl V-(ferf-butoxycarbonyl)-4-[3-
Figure imgf000101_0002
Another preferred compound of Formula IV is di-fert-butyl 2-[(fert-butoxycarbonyl)- ioate:
Figure imgf000101_0003
Another preferred compound of Formula IV is di-ferf-butyl /V-(iert-butoxycarbonyl)-4-[(5- hydroxypyridin-2-yl)methyl]glutamate
Figure imgf000101_0004
Another more preferred compound of Formula IV is di-ferf-butyl (4S)-4-(4-aminobenzyl)- W-(fert-butoxycarbonyl)-L-glutamate:
Figure imgf000102_0001
Another more preferred compound of Formula IV is di-fert-butyl (4S)-/V-(tert-butoxy- carbonyl)-4-[4-(3-hydroxypropyl)benzyl]-L-glutamate:
Figure imgf000102_0002
Another more preferred compound of Formula IV is di-fert-butyl (4S)-/V-(fert-butoxy- carbonyl)-4-[3-(4-hydroxyphenyl)propyl]-L-glutamate:
Figure imgf000102_0003
Another more preferred compound of Formula IV is di-ferf-butyl (2S)-2-[(iert-butoxy- carbonyl)amino]-5-(4-hydroxybenzyl)hexanedioate:
Figure imgf000102_0004
Another more preferred compound of Formula IV is di-fert-butyl (2R)-2-[(ferf-butoxy- carbonyl)amino]-5-(4-hydroxybenzyl)hexanedioate:
Figure imgf000103_0001
Another more preferred compound of Formula IV is di-fert-butyl (AR)-N-(tert- butoxycarbonyl)-4-[(5-hydroxypyridin-2-yl)methyl]-L-glutamate
Figure imgf000103_0002
Another more preferred compound of Formula IV is di-fert-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-[(5-hydroxypyridin-2-yl)methyl]hexanedioate:
Figure imgf000103_0003
Another more preferred compound of Formula IV is di-fert-butyl (2S)-2-[(fert- xyphenyl)ethyl]hexanedioate:
Figure imgf000103_0004
Another more preferred compound of Formula IV is (2S)-2-iert.-Butoxycarbonylamino-5-
(4-hydroxy-benzyl)-hexanedioic acid di-fert. -butyl ester:
Figure imgf000104_0001
Another more preferred compound of Formula IV is (2S)-2-amino-5-(4- id:
Figure imgf000104_0002
Another more preferred compound of Formula IV is (2S.5R)-2-amino-5-(4- id:
Figure imgf000104_0003
Another more preferred compound of Formula IV is (2S.5S)-2-amino-5-(4- id:
Figure imgf000104_0004
Another more preferred compound of Formula IV is dimethyl (2S)-2-amino-5-(4-
Figure imgf000104_0005
Another more preferred compound of Formula IV is di-fert-butyl (4S)-N-(iert- droxyethoxy)benzyl]-L-glutamate:
Figure imgf000105_0001
Another more preferred compound of Formula IV is di-tert-butyl (5S)-2-(4-aminobenzyl)- dioate:
Figure imgf000105_0002
The seventh aspect of the present invention is directed to methods for preparation of compound of Formula III (Radiopharmaceutical)
In a first embodiment, the invention is directed to a method for preparation of compound of Formula III comprising the steps of:
18F-radiofluorination of compound of Formula I to obtain compound of Formula II, and
- Cleavage of protecting groups from compound of Formula II to obtain compound of Formula III.
Optionally the method is followed by the purification of compound of Formula III by solid-phase-extraction. Preferably solid-phase-extraction cartridges or column is used.
The preferred features and embodiments disclosed for compounds of general formula I, II and III are herein incorporated. Methods for 18F-fluorination are well known to the person skilled in the art. For example, the 18F-Fluorination agent can be K 8F, H18F, Rb18F, Cs18F, Na18F.
Optionally, the 18F-Fluorination agent comprises a chelating agent such as a cryptand (e.g.: 4,7, 13.16,21 ,24-Hexaoxa-1 , 10-diazabicyclo[8.8.8]-hexacosane - Kryptofix®) or a crown ether (e.g.: 18-crown-6).
The 18F-Fluorination agent can also be a tetraalkylammonium salt of 8F~ or a tetraalkylphosphonium salt of ,8F", known to those skilled in the art, e.g.: tetrabutylammonium [18F]fluoride, tetrabutylphosphonium [ 8F]fluoride.
Preferably, the 18F-Fluorination agent is Cs 8F, K18F, tetrabutylammonium [ 8F]fluoride.
The reagents, solvents and conditions which can be used for this fluorination are common and well-known to the skilled person in the field. See, e.g., J. Fluorine Chem. , 27 (1985): 177-19 ; Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P.A., Friebe M., Lehmann L., (eds), PET- Chemistry - The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp.15- 50). Preferably, the solvents used in the present method are DMF, DMSO, acetonitrile, DMA, or mixtures thereof, preferably the solvent is acetonitrile, DMSO.
In a second embodiment, the invention is directed to a method for preparation of compounds of Formula III, wherein L1 is alkylene-O, alkylene-NH or cycloalkylene-O, comprising the steps of:
Reacting of a compound of Formula IV, wherein Z is OH or NH2, with an 18F labeled building block VII, and
- Optionally, cleaving of protecting groups to obtain a compound of Formula III.
Optionally the method is followed by the purification of compound of Formula III by solid-phase-extraction. Preferably solid-phase-extraction cartridges or column is used. [18F]Fluorine containing building block is a compound of formula VII
18F-L'-LG
VII
wherein
LG is defined as above, and
L' is alkylene or cycloalkylene as defined above. The preferred features and embodiments disclosed for compounds of general formula III and IV are herein incorporated.
In a more preferred embodiment, a compound of Formula IV, wherein Z is OH and R1 is H and R2 is H and R3 is H and R4 is H is reacted with a building block selected from 18F- CH2-LG and 8F-CH2-CH2-LG.
The eighth aspect of the present invention is directed to methods for preparation of compound of Formula VI (cold standard).
In a first embodiment, the invention is directed to a method for preparation of compound of Formula VI comprising the steps of:
Fluorination of compound of Formula I to obtain compounds of Formula V, and - Cleavage of protecting groups from compound of Formula V to obtain compound of
Formula VI.
Optionally the method is followed by the purification of compound of Formula VI. Suitable purification methods are chromatography methods (e.g. HPLC, flash- chromatography).
The preferred features and embodiments disclosed for compounds of general formula I, V and VI are herein incorporated. In a second embodiment, the invention is directed to a method for preparation of compound of Formula VI comprising the steps of
Reacting of compound of Formula IV with a fluorine containing building block VIII or with a fluorinating reagent and
Optionally, cleaving of protecting groups to obtain compound of Formula VI.
Optionally the method is followed by the purification of compound of Formula VI. Suitable purification methods are chromatography methods (e.g. HPLC, flash- chromatography). Fluorine containing building block is a compound of formula VIII F— L'-LG
VIII
wherein
LG is defined as above, and
L' is alkylene or cycloalkylene as defined above.
The fluorinating reagent is a suitable reagent for the reaction and is exemplified by but not limited to DAST or nonafluorobutylsulfonyl fluoride.
F is a cold fluorine isotope [!9F1.
The preferred features and embodiments disclosed for compounds of general formula IV and VI are herein incorporated.
The ninth aspect of the present invention is directed to methods for preparation of compound of Formula I (precursor).
In a first embodiment, the invention is directed to a method for preparation of compound of Formula I comprising the steps of:
Introducing a leaving group to compounds of Formula IV wherein Z is OH-L.
Optionally the method is followed by the purification of compound of Formula I. Suitable purification methods are chromatography methods (e.g. HPLC, flash-chromatography). The preferred features and embodiments disclosed for compounds of general formula I and IV are herein incorporated.
In a second embodiment, the invention is directed to a method for preparation of compound of Formula I, wherein L is alkylene-O, alkylene-NH or cycloalkylene-O, comprising the steps of:
Reacting of compound of Formula IV, wherein Z is OH or Nh with a building block of formula IX
wherein compound of formula IX is LG-L'-LG'
IX
LG is described above and LG' is a leaving group selected from the group of
a) Sulfonate leaving group, and
b) Halogen, and
L' is alkylene or cycloalkylene.
Optionally the method is followed by the purification of compound of Formula I. Suitable purification methods are chromatography methods (e.g. HPLC, flash-chromatography). The preferred features and embodiments disclosed for compounds of general formula IV and I are herein incorporated.
In a tenth aspect of the present invention compounds of Formula III are provided as medicament or pharmaceutical.
The invention relates also to the use of compound of Formula III for the manufacture of medicament or pharmaceutical for treatment.
In a eleventh aspect of the invention, compounds according to Formula III for the manufacture of an imaging tracer or radiopharmaceutical agent for imaging proliferative diseases. The imaging agent or radiopharmaceutical agent is preferably suitable as imaging agent for PET applications. In other words, the invention is directed to compound of general formula III as imaging tracer or radiopharmaceutical agent.
The invention is directed to compound of general formula III for use in the imaging of proliferative diseases.
The invention is also directed to a method for imaging or diagnosing of proliferative diseases comprising the steps:
Administering to a mammal an effective amount of a compound comprising compound of formula III,
- Obtaining images of the mammal and Assessing images.
In a more preferred embodiment the use concerns the imaging of proliferative diseases. Proliferative diseases in oncology are characterized by the presence of tumor and/or metastases. Preferably tumors include but are not limited to malignomas of the gastrointestinal or colorectal tract, liver carcinoma, pancreas carcinoma, kidney carcinoma, bladder carcinoma, thyroid carcinoma, prostate carcinoma, endometrial carcinoma, ovary carcinoma, testes carcinoma, melanoma, small-cell and non-small- cell lung carcinoma, dysplastic oral mucosa carcinoma, invasive oral cancer; breast cancer, including hormone-dependent and hormone-independent breast cancer, squamous cell carcinoma, neurological cancer disorders including neuroblastoma, glioma, astrocytoma, osteosarcoma, meningioma, soft tissue sarcoma, haemangioma and endocrine tumors, including pituitary adenoma, chromocytoma, paraganglioma, haematological tumor disorders including lymphoma and leukaemias. Preferably, metastases are metastases of one of the tumors mentioned above.
The present invention is also directed to a method of imaging comprising the step of introducing into a patient a detectable quantity of an 18F labeled compound of Formula III and imaging said patient.
Another aspect of the invention is the use of a compound of Formula III as described above and herein for diagnosing and/or treating oncology disease in a patient, in particular in a mammal, such as a human. Preferably, the use of a compound of the invention in the diagnosis is performed using positron emission tomography (PET).
Another aspect of the invention is directed to a method of imaging tumors. Such a method comprises a) administering to a mammal a compound as described above and herein containing a detectable label, and b) detecting the signal stemming from the compound that is specifically taken up by a tumor.
In a further aspect, the invention is directed to a method of diagnosing a patient with oncology disease. This method comprises a) administering to a human in need of such diagnosis a compound of the invention with a detectable label for detecting the compound in the human as described above and herein, and b) measuring the signal from the detectable label arising from the administration of the compound to the human, preferably by positron emission tomography (PET).
Methods of diagnosing and use for PET imaging of proliferative diseases involve adimistration of one of the preferred compounds listed below:
(4S)-4-[4-(2-[18F]Fluoroethoxy)benzyl]-L-glutamic acid
Figure imgf000111_0001
(4S)-4-[4-(3-[18F]Fluoropropoxy)benzyl]-L-glutamic acid
Figure imgf000111_0002
4-{4-[(3-[18F]Fluoropropyl)amino]benzyl}-L-glutamic acid
Figure imgf000111_0003
8F]fluoroethoxy)benzyl]hexanedioic acid
Figure imgf000111_0004
and stereoisomers and mixtures thereof.
In a twelfth aspect, the invention is directed to a kit comprising one vial or more than one vial comprising a predetermined quantity of:
a) compounds of Formula I or Formula IV. or
b) compounds of Formula VI. Further, according to this aspect of the present invention the kit comprises a compound having general chemical Formula as disclosed above along with an acceptable carrier, diluent, excipient or adjuvant or mixture thereof.
Preferably, the Kit comprises physiologically acceptable vehicle or carrier and optional adjuvants and preservatives, reagents suitable to perform the herein disclosed reactions and/or to generate the [18F] labeling reagents. Furthermore, the kit may contain instructions for its use.
In a thirteenth aspect, the invention is directed to the use of compounds of general formula III or VI for conducting biological assays and chromatographic identification. More preferably, the use relates to compounds of general formula VI.
Compounds of general formula VI are useful as references and/or measurement agents.
The compounds of general formula III and VI are herein defined as above and encompass all embodiments and preferred features.
In a fourteenth aspect, the invention is directed to a composition comprising compounds of formula I, II, III, IV, V or VI as defined in the above aspects and included embodiments.
In a first embodiment, the invention is directed to a composition comprising compound of formula III and pharmaceutically suitable adjuvants. These adjuvants include, inter alia, carriers, solvents, or stabilizers.
The person skilled in the art is familiar with adjuvants which are suitable for the desired pharmaceutical formulations, preparations or compositions on account of his/her expert knowledge.
The administration of the compounds, pharmaceutical compositions or combinations according to the invention is performed in any of the generally accepted modes of administration available in the art. Intravenous deliveries are preferred.
Preferably, the compositions according to the invention are administered such that the dose of the active compound for imaging is in the range of 37 MBq (1 mCi) to 740 MBq (20 mCi). In particular, a dose in the range from 100 MBq to 400 MBq will be used.
Preferably, the composition comprises one of the compounds disclosed below (4S)-4-[4-(2-[18F]Fluoroethoxy)benzyl]-L-glutamic acid
Figure imgf000113_0001
(4S)-4-[4-(3-[18F]Fiuoropropoxy)benzyl]-L-glutamic acid
Figure imgf000113_0002
4-{4-[(3-[18F]Fluoropropyl)amino]benzyi}-L-glutamic acid
Figure imgf000113_0003
18F]fluoroethoxy)benzyl]hexanedioic acid
Figure imgf000113_0004
stereoisomers and mixtures thereof, and suitable salts thereof, and pharmaceutically acceptable carriers or diluents as described above.
In a second embodiment, the invention is directed to a composition com compound of formula VI. Such composition can be used for analytical purposes.
Preferably, the composition comprises one of the compounds disclosed below
(4S)-4-[4-(2-Fluoroethoxy)benzyl]-L-glutamic acid
Figure imgf000113_0005
(4S)-4-[4-(3-Fluoropropoxy)benzyl]-L-glutamic acid
Figure imgf000114_0001
Figure imgf000114_0002
Figure imgf000114_0003
In a third embodiment, the invention is directed to a composition comprising compound of formula I or IV. Such composition can be used for manufacturing of compound of formula III (radiopharmaceutical ) and/or VI (cold standard).
Preferably, the composition comprises one of the compounds disclosed below:
thoxy]benzyl}-L-glutamate:
ropoxyjbenzyl}-L-glutamate:
Figure imgf000114_0004
di-ferf-butyl (4S)-W-(ferf-butoxycarbonyl)-4-(4-{[3-(tosyloxy)propyl]amino}benzyl)-L-
Figure imgf000115_0001
di-ferf-butyl (2S)-2-[(ferf-butoxycarbonyl)amino]-5-{4-[2-(tosyloxy)ethoxy]bi
Figure imgf000115_0002
, and stereoisomers thereof.
DEFINITIONS
The following terms describe generic and specific structural elements of the chemical scaffold of the compounds of the present invention, as well as functional groups and substituents attached thereto. They can be combined in a way resulting in structures in line with the chemical valency rules and of suitable chemical stability, that is, compounds that are sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and for their intended use, such as formulation into a pharmaceutical composition. For the purposes of the present invention, the terms have the following meaning, unless otherwise specified:
"Alkyl" per se and "alk" and "alkyl" in alkoxy, alkylcarbonyl, alkylamino, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino and alkylcarbonylamino represent a linear or branched alkyl radical having, as a rule, 1 to 6, preferably 1 to 4, especially preferably 1 to 3, carbon atoms, by way of example and by preference methyl, ethyl, n-propyl, /so-propyl, fert-butyl, n-pentyl and n-hexyl.
As used herein, the term "alkylene" refers to linear or branched saturated bivalent chain of carbon atoms having, as a rule, 1 to 6, preferably 1 to 4, especially preferably 1 to 3, carbon atoms, by way of example and including but not limited to methylene, ethylene, propylene, butylene, pentylene, hexylene, so-propylene, /so-butylene, sec-butylene, fert-butylene, /so-pentylene, 2-methylbutylene, 1 -methylbutylene, 1 -ethylpropylene, 1 ,2- dimethylpropylene, neo-pentylene, 1 , 1-dimethylpropylene, 4-methylpentylene, 3- methylpentylene, 2-methylpentylene, 1 -methylpentylene, 2-ethylbutylene, 1- ethylbutylene, 3,3-dimethylbutylene, 2.2-dimethylbutylene, 1 .1 -dimethylbutylene, 2,3- dimethylbutylene. 1 ,3-dimethylbutyene, 1 .2-dimethylbutylene and by preference methylene, ethylene and propylene. "Cycloalkylene" represents an alicyclic bivalent group of carbon atoms having 3 to 8, preferably 5 to 7, carbon atoms, by way of example and by preference cyclopropylene, cyclobutylene, cyclopentylene and cyclohexylene.
"Arylene" represents a mono- or bicyclic aromatic, carbocyclic bivalent radical having, as a rule, 6 to 10 carbon atoms, optionally substituted by one or two "substituents"; by way of example and by preference phenylene. "Heteroarylene" represents an aromatic, mono- or bicyc!ic bivalent radical having, as a rule, 5 to 10, preferably 5 to 6, ring atoms and up to 3, preferably 1 , hetero atoms from the series consisting of S, O and N: by way of example and including but not limited to thienylene, furylene, pyrrolylene, thiazolylene, oxazolylene, imidazolylene, pyridylene, pyrimidylene, pyridazinylene, indolylene, indazolylene, benzofuranylene, benzothiophenylene, quinolinylene, isoquinolinylene, triazolylene. Wherein said "heteroarylene" is optionally substituted by one or two "substituents". Preferably, "heteroarylene'' is pyridylene or triazolylene. "Substituent" as used herein represents alkyl, trifluormethyl, fluoro, chloro, cyano, nitro, hydroxyl, protected hydroxyl, alkoxy; preferably methoxy, ethoxy, hydroxyl, protected hydroxyl.
"Halogen" represents fluorine, chlorine, bromine and iodine.
The term "amine-protecting group" as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely carbamates, amides, imides, N-alkyl amines, N-aryl amines, imines, enamines, boranes, N-P protecting groups, N-sulfenyl, N-sulfonyl and N-silyl, and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 494-653, included herewith by reference. The "amine-protecting group" is preferably carbobenzyloxy (Cbz), p-methoxybenzyl carbonyl (Moz or MeOZ), tert- butyloxycarbonyl (BOC), 9-fluorenylmethyloxycarbonyl (FMOC), benzyl (Bn), p- methoxybenzyl (PMB), 3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), triphenylmethyl (Trityl), methoxyphenyl diphenylmethyl (MMT) or the protected amino group is a 1 .3-dioxo-1 ,3-dihydro-2H-isoindol-2-yl (phthalimido) or an azido group.
"Carboxyl-protecting group" as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely esters, amides and hydrazides, and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 369-453, included herewith by reference. The "carboxyl-protecting group" is preferably methyl, ethyl, propyl, butyl, tert- butyl, allyl, benzyl, 4-methoxybenzyl or 4-methoxyphenyl.
"Hydroxvl-protecting group" as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely ethers, esters, and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 17-200, included herewith by reference.
Hydroxyl protecting group which is chosen from but not limited to a class of protecting groups namely ethers, esters such as t-butyl, benzyl, p-methoxybenzyl, p-nitrobenzyl, allyl, trityl, methoxymethyl, methoxyethoxymethyl, ethoxyethyl, 1-methyl-1- methoxyethyl, tetrahydropyranyl, trialkylsilyl; benzoyl, acetyl, and phenylacetyl. Additionally, for the protection of 1 ,2- and 1 ,3-diols, one or two "hvdroxvl-protectinq groups" as employed herein by itself or as part of another group for is known or obvious to someone skilled in the art, which is chosen from but not limited to a class of protecting groups namely cyclic acetals, cyclic ketals, cyclic ortho esters, silyl derivatives, cyclic carbonates and cyclic boronates such as methylene, ethylidene, benzylidene, isopropylidene, cyclohexylidene, cyclopentylidene, and di-t-butylsilylene , and which is chosen from but not limited to those described in the textbook Greene and Wuts, Protecting groups in Organic Synthesis, third edition, page 201-245, included herewith by reference. The term "leaving group" as employed herein by itself or as part of another group is known or obvious to someone skilled in the art, and means that an atom or group of atoms is detachable from a chemical substance by a nucleophilic agent. Examples are given e.g. in Synthesis (1982), p. 85-125, table 2 (p. 86; (the last entry of this table 2 needs to be corrected: "n-C.iFgS(0)2-0- nonaflat" instead of "n-C.iHgS(0)2-0- nonaflat"), Carey and Sundberg, Organische Synthese, (1995), page 279-281 , table 5.8; or Netscher, Recent Res. Dev. Org. Chem., 2003, 7, 71-83, scheme 1 , 2, 10 and 15 and others). (Coenen, Fluorine-18 Labeling Methods: Features and Possibilities of Basic Reactions, (2006), in: Schubiger P.A., Friebe M., Lehmann L, (eds), PET-Chemistry - The Driving Force in Molecular Imaging. Springer, Berlin Heidelberg, pp.15-50, explicitly: scheme 4 pp. 25, scheme 5 pp 28, table 4 pp 30, Figure 7 pp 33).
Preferably, the "leaving group" is Br, I or a sulfonate leaving group including but not limited to methylsulfonyloxy. (4-methylphenyl)sulfonyloxy, trifluormethylsulfonyloxy, nonafluorobutylsulfonyloxy, (4-bromo-phenyl)sulfonyloxy, (4-nitro-phenyl)sulfonyloxy, (2-nitro-phenyl)sulfonyloxy, (4-isopropyl-phenyl)sulfonyloxy, (2,4,6-tri-isopropyl- phenyl)sulfonyloxy, (2.4.6-trimethyl-phenyl)sulfonyloxy, (4-tertbutyl-phenyl)sulfonyloxy, (4-methoxy-phenyl)sulfonyloxy, etc. If chiral centers or other forms of isomeric centers are not otherwise defined in a compound according to the present invention, all forms of such stereoisomers, including enantiomers and diastereoisomers, are intended to be covered herein. Compounds containing chiral centres may be used as racemic mixture or as an enantiomerically enriched mixture or as a diastereomeric mixture or as a diastereomerically enriched mixture, or these isomeric mixtures may be separated using well-known techniques, and an individual stereoisomer maybe used alone. In cases wherein compounds may exist in tautomeric forms, each tautomeric form is contemplated as being included within this invention whether existing in equilibrium or predominantly in one form.
Suitable salts of the compounds according to the invention include salts of mineral acids, carboxylic acids and sulfonic acids, for example salts of hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, naphthalene disulfonic acid, acetic acid, trifluoroacetic acid, propionic acid, lactic acid, tartaric acid, malic acid, citric acid, fumaric acid, maleic acid and benzoic acid.
Suitable salts of the compounds according to the invention also include salts of customary bases, such as, by way of example and by way of preference, alkali metal salts (for example sodium salts and potassium salts), alkaline earth metal salts (for example calcium salts and magnesium salts) and ammonium salts, derived from ammonia or organic amines having 1 to 16 carbon atoms, such as, by way of example and by way of preference, ethylamine, diethylamine, triethylamine, ethyldiisopropylamine, monoethanolamine, diethanolamine, triethanolamine, dicyclohexylamine. dimethylaminoethanol, procaine, dibenzylamine, N- methylmorpholine, arginine, lysine, ethylenediamine and N-methylpiperidine.
The term "purification" as employed herein has the objective to eliminate the excess of side product such as 8F-Fluoride and to concentrate and trap the reaction product. Purification is carried out by any method known to those in the art, suitable for radiotracer e.g. chromatography, HPLC, solid-phase-extraction cartridges or column. ABBREVIATIONS
Figure imgf000120_0001
NMR nuclear magnetic resonance
spectroscopy : chemical shifts (δ) are given in ppm.
PET Positron-Emmision-Tomography
PMB para-methoxybenzyl
q quadruplett (quartet)
RT room temperature
s singulet
t triplet
TBDMS fert-butyldimethylsilyl
Trt trityl (=triphenylmethyl)
THF tetrahydrofuran
THP tetrahydropyran
TLC thin layer chromatography
Ts tosyl, 4-methylphenyl)sulfonyl
TsO tosyloxy, 4-methylphenyl)sulfonyloxy
UPLC Ultra Performance Liquid Chromatography
GENERAL SYNTHESIS
A. Alkylation of qlutamate backbone
Compounds of the invention in which X stands for CH2 can be approached by alkylation of g
Figure imgf000122_0001
Scheme 1 Alkylation of glutamate backbone (R1, R2. R3, R3, R4, A. Q. Z, L are described above, RA2 is a leaving group, RA1 is Z or L, a derivative of Z or L or can be subsequently transformed to Z or L or a derivative of Z or L)
R*2 acts as a leaving group (for example Br, I, sulfonate) and RA1 is Z or L, a derivative of Z or L or can be subsequently transformed to Z or L or a derivative of Z or L.
The alkylation of glutamate derivatives is described in the literature, e.g.: M. A. Brimble et al., Bioorg. Med. Chem. 2005, 13, 519-523; S. Hanessian et al.. J. Org. Chem. 2005, 70, 5070-5085; S. Hanessian et al., Org. Lett. 2004, 6, 4683-4686; J. Zhang et al., Tetrahedron Lett. 2003, 44, 1413-1415. It is well known, that the alkylation affords selectively compounds A-3 if R3 is hydrogen and R4 is a carbamate-type protecting group (e.g. Boc). Mixtures of A-3 and A-4 can be obtained and separated by chromatography methods if other combinations of R3 and R4 are used (e.g. R3 = hydrogen and R4 = Trityl).
Corresponding D-glutamate derivatives can be obtained if D-glutamate building blocks A-5 are used (Scheme 2).
Figure imgf000123_0001
Scheme 2 Alkylation of D-glutamate backbone (R>. R2. R3. R3, R4, A. Q. Z. L are described above. RA2 is a leaving group. RA1 is Z or L. a derivative of Z or L or can be subsequently transformed to Z or L or a derivative of Z or L)
Compounds wherein X stands for -CH2- and A stands for propyl can be obtained by alkylation of compounds A-1 or A-5 using allyl bromide (as described in the literature cited above) and subsequent cross-coupling with aryl/heteroaryl halides or sulfonates, followed by hydrogenation.
Synthesis of homoqlutamate derivatives
Compounds of the invention in which X stands for CH2-CH2 can be approached as shown in Scheme 3. The synthesis commences with the alkylation of phosphono- acetates B-1 with appropriately substituted arenes or heteroarenes B-2 to give phosphonate intermediates B-3. Compounds of the formula B-2 are often known to the person skilled in the art and commercially available in some cases. Multiple syntheses of compounds of the formula B-2. and of useful intermediates for their preparation are described in the scientific literature, see e.g. Helv. Chem. Acta 2002. 85, 3422, J. Med. Chem. 1977, 20. 1258, Coll. Czechoslovak Chem. Comm. 1948, 13. 289, J. Am. Chem. Soc. 1958, 80. 2217, EP 379928.
Subsequently, compounds of formula B-3 are, following deprotonation with an appropriate base, reacted with aldehydes B-4 to give olefins B-5a and B-5b, typically as mixture of double bond isomers. Aldehydes B-4 are available from the corresponding homo-serine derivatives, which are known to the person skilled in the art, by standard oxidation reaction, e.g. by hypervalent iodine based reagents such as Dess-Martin's periodinane.
The double bond present in B-5a and B-5b is then saturated e.g. by catalytic hydrogenation, and Z' is transferred into Z by removal of the corresponding protecting group. This can be accomplished in one single step if said protecting group is amenable for hydrogenolytic cleavage. This leads to compounds B-6 which are equivalent to compounds of the formula IV with the proviso that X stands for an ethylene group.
Figure imgf000124_0001
Scheme 3 Preparation of compounds of the formula B-6. wherein R1. R2. R3,
R4, A. and Q are defined as in the claims and description of this invention, and wherein Ra is a Ci-Ce alkyl group, and Z' stands for Z as defined as in the claims and description of this invention with the proviso that Z' is not a halogen, and Z" stands for a protected form of Z wherein the hydroxy! group contained in Z' is protected by a suitable hydroxyl-protecting group known to the person skilled in the art and as described in the definitions and in the literature cited herein, furthermore Z" can be nitro as a protected synthon if Z' NH2.
Alternatively, compounds of the formula B-6 can be prepared starting from orthogonally protected malonic esters B-7 which can be sequentially alkylated by reactive homo-serine derivatives B-8, followed by alkylation of the resulting product B-9 with compounds of the formula B-2 to give B-10. Subsequently, Rb is selectively cleaved in the presence of the other carboxylate protecting groups to yield the corresponding monocarboxylic acid, which is then decarboxylated to give compounds of the formula B-6. In addition, Z" is converted into Z'; most advantageously, the protecting group present in Z" is chosen suitably to enable simultaneous cleavage with RD, for example by hydrogenolysis. The person skilled in the art will readily recognize the advantage of this synthetic route for the introduction of a diverse set of Z"-Q-A- groups. It could be shown that stereochemical information present in the homo-serine derivative B-8 can be retained over both malonate alkylation steps. In addition, the chiral HPLC methods used herein offer the possibility to isolate and characterize single stereoisomers.
Figure imgf000125_0001
Scheme 4 Alternative Preparation of compounds of the formula B-6, wherein R R2, R3, R4, A, and Q are defined as in the claims and description of this invention, and wherein Z' stands for Z as defined as in the claims and description of this invention with the proviso that Z' is not a halogen, and Z" stands for a protected form of Z wherein the hydroxy! group contained in Z' is protected by a suitable hydroxyl-protecting group known to the person skilled in the art and as described in the definitions and in the literature cited herein. Rb is a group which can be removed in the presence of other protecting groups present in intermediate B-10. e.g. other carboxyl- and amine-protecting groups, which can be exemplified by but is not limited to an optionally substituted benzylic group.
Subsequently, compounds of the formula B-6, constituting a sub-set of compounds of formula IV, can be elaborated into compounds of the formula I as outlined in the following paragraph (if Z' stands for OH), or, if T stands for HO-L, by conversion of the terminal hydroxyl group into a leaving group. If said leaving group is a sulfonate, this can be accomplished by standard sulfonylation procedures well known to the person skilled in the art, such as treatment of the respective hydroxyl compound with a sulfonyl halide (such as tosyl chloride) or a sulfonyl anhydride in the presence of a suitable base, such as pyridine, 2,6-lutidine, or triethylamine. If said leaving group is Br or I, conversion can be performed by reacting the respective hydroxyl compound e.g. with a triaryl phosphine and the respective /V-halo succinimide (see examples section) or carbon tetrahalide. To facilitate work-up and product purification, the triaryl phosphine may also be used as a polymer bound reagent. Using the methods described above compounds of compounds of the formula B-6' and B-6" can be synthesized by a sequence starting by reacting compounds of formula B-8' and B-8" with of formula B-7 (Scheme 4-B).
Figure imgf000127_0001
A
I
B-2
Figure imgf000127_0002
Scheme 4-B Preparation of compounds of the formula B-6' and B". wherein
R1, R2, R3, R4, A, and Q are defined as in the claims and description of this invention, and wherein Z' stands for Z as defined as in the claims and description of this invention with the proviso that Z' is not a halogen, and Z" stands for a protected form of Z wherein the hydroxy! group contained in Z' is protected by a suitable hydroxyl-protecting group known to the person skilled in the art and as described in the definitions and in the literature cited herein. R" is a group which can be removed in the presence of other protecting groups present in intermediate B-10. e.g. other carboxyl- and amine-protecting groups, which can be exemplified by but is not limited to an optionally substituted benzylic group. Alkylation of arvl/heteroaryl-OH
Numerous methods and variations for the transformation of hydroxyl substituted aryl or heteroaryl derivatives into their corresponding aikyl aryl ethers or alkyl heteroaryi ethers have been reported (for an overview see for example: R. C. La rock, in "Comprehensive Organic Transformations." 2nd ed., John Wiley & Sons, Inc., New York (1999), p 889). Hence, compounds of this invention, wherein L stands for alkylene-O can be obtained by conversion of hydroxyl substituted aryl- or heteroaryl derivatives C-1 according to Scheme 5. Compounds of formula C-7 can serve as intermediates for the synthesis of compounds of formula I and compounds of formula V. For example, RC1 can be deprotected and the resulting free hydroxyl group can be further converted either into a leaving group (applying methods described above) to give compounds of formula I, or into a fluoride (applying
Figure imgf000128_0001
Figure imgf000128_0002
Scheme 5 Alkylation of hydroxyl-substituted aryl or heteroaryl derivatives (R1, R2, R3. R4, LG. LG A. Q. X are described above. RC1 is an optionally protected hydroxyl group. L ' is optionally substituted alkylene or cycloalkylene. L " stands for L as defined in the claims and description of this invention with the proviso that L " contains at least one oxygen atom and the bond between Q and L " is a bond between Q and one oxygen atom of L ' and n is 1-4') Alternatively, certain compounds of formula C-7, can be obtained by reactions of compounds of formula C-1 with compounds of formula C-8 (Scheme 6) under conditions known to the person skilled in the art (Bull. Chem. Soc. Jpn. 1967, 40, 4235: Chem. Lett 2001 , 2, 94; J. Org. Chem. 1998, 63, 8554).
Figure imgf000129_0001
Scheme 6 Reaction of hydroxy! substituted aryl or heteroaryl derivatives C-1 with alcohols according to formula C-8 (R1, R2. R3, R4. A. Q. X are described above. L' is optionally substituted alkylene or cycloalkylene, L " stands for L as defined as in the claims and description of this invention with the proviso that L " contains at least one oxygen atom and the bond between Q and L " is a bond between Q and one oxygen atom of L ". RC1 is an optionally protected hydroxy! group).
Alternatively, compounds of formula C-7 can be obtained by reactions of compounds of formula C-9 with compounds of formula C-8 (Scheme 7) under conditions known to the person skilled in the art (For examples, see: J. Am. Chem. Soc. 2005, 127, 8146; J. Org. Chem. 2009, 74 , 5075: J. Am. Chem. Soc. 2001 , 123, 10770; Tetrahedron Lett. 2006, 47, 5333; J. Med. Chem. 1996, 39. 3837; Tetrahedron Lett. 2007, 48 , 4293)
Figure imgf000129_0002
C-9 C-8 C-7
Scheme 7 Reaction of aryl or heteroaryl derivatives C-9 with alcohols according to formula C-8 (R1, R2. R3. R4, A, Q, X are described above. L' is optionally substituted alkylene or cycloalkylene, L " stands for L as defined as in the claims and description of this invention with the proviso that L " contains at least one oxygen atom and the bond between Q and L " is a bond between Q and one oxygen atom of L ". LG' is halogen. RC1 is an optionally protected hydroxy! group)
Alkylation of aryl/heteroarvl-NH? Compounds, wherein L stands for alkylene-NH can be obtained by conversion of aniline derivatives D-1 (Scheme 8) as known to the person skilled in the art, e.g. by alkylation using compounds C-2 or C-4, or by reductive amination using compounds
D-4.
Figure imgf000130_0001
Scheme 8 Alkylation of aniline derivatives (R>, R2. R3. R3, R4, LG. LG'. A. Q.
X are described above)
Synthesis of alkylaryl derivatives and building blocks
Compounds of this invention, where L stands for alkylene or substituted alkylene, can be synthesized according to Scheme 9 by reacting compounds of formula C-9 with suitable alkenes of formula E-1 (see for example Synthesis 2005, 20, 3589), alkynes of formula E-3 (see for example Organic Lett. 2002, 4, 141 1 ; J. Org. Chem. 2003, 68, 3327), alkenyl metal species of formula E-5 (see for example Collect. Czech. Chem. Commun. 2000, 65, 434; Organic Lett. 2000, 2, 565; SYNLETT 2002, 7, 1 137; Tetrahedron Lett. 1992, 33, 6139; Tetrahedron Lett. 2002. 43, 4935), or alkyl metal species of formula E-6 (see for example Tetrahedron Lett. 1994, 35, 1 177; Liebigs Ann. Chem. 1991 , 3, 295; Bull. Chem. Soc. Jpn. 1997, 70, 437; Tetrahedron 1998, 54, 197; Tetrahedron Lett. 1999, 40, 197; Tetrahedron Lett. 2004, 45, 2467) under conditions described in the literature and known to the person skilled in the art (wherein metal includes, but is not limited to Sn, Si, Mg, Zn, and B in their appropriate oxidation states and further substituted by suitable ligands in order to facilitate the cross coupling reactions described in Scheme 9 and in the literature cited above). Compounds of formulas E-2, E-4 and E-7 can further be elaborated into compounds of formula I and compounds of formula V by methods known to the person skilled in the art. In case of compounds of formula E-2 and E-4, the non-aromatic double bonds and triple bonds can be saturated e.g. by hydrogenolysis. This may also deprotect the RC1 hydroxy I group, if the protecting group is chosen accordingly (e.g. benzyl protecting group), which might otherwise be deprotected before or subsequently by other means (e.g. using TBAF in case of silicon based protecting groups). Deprotection of the RC1 hydroxy I group of E-7 can be achieved similarly. In some cases, the corresponding building blocks comprising unprotected hydroxy I groups may also be used. The so-derived free hydroxyl groups of compounds of formula E-7 can be transformed by methods described above into suitable leaving groups to give compounds of formula I, or into fluoride to give compounds of formula V.
Figure imgf000132_0001
Figure imgf000132_0002
C-9 E-3
Figure imgf000132_0003
C-9 E-6 E-7
Scheme 9 Reaction of aryl or heteroaryl derivatives C-9 with alkenes, alkynes, alkenyl metal derivatives, and alkyl metal derivatives (R1, R2, R3, R4, A, Q, X, LG' are described above, L ' is optionally substituted alkylene or cycloalkylene, L '" stands for L as defined as in the claims and description of this invention with the proviso that the bond between Q and L'" Q is a bond between Q and one carbon atom of L " RC1 is an optionally protected hydroxy I group, M* is a metal atom in an appropriate oxidation state and may be further substituted by suitable ligands)
Alternatively, compounds of formula E-1 , E-3, E-5, and E-6 can be used in the same manner as described for reactions with compounds of formula C-9 for reactions with compounds of formula E-8 (Scheme 10). Non aromatic double bonds and triple bonds can be saturated e.g. by hydrogenolysis. A' can be transformed into A-RA2. For example, if A' is optionally protected hydroxyalkyl, deprotection of the hydroxyl group and subsequent conversion into a halide or sulfonate leads to compounds of formula E-10 or E-13, which can be used in the same manner as compounds of formulas A-2 and B-2 in the respective examples.
Figure imgf000133_0001
E-8 E-1 E-9 E-10
Figure imgf000133_0002
E-8 E-3 E-11 E-10
Figure imgf000133_0003
E-8 E-5 E-9 E-10
Figure imgf000133_0004
E-8 E-6 E-12 E-13
Scheme 10 Reaction of aryl or heteroaryl derivatives E-8 with alkenes, alkynes, alkenyl metal derivatives, and alkyl metal derivatives (A, Q, LG ', L RC , RA2, M* are described above. A ' is a residue which can be transformed into A-RA2 by methods known to the person skilled in the art).
Synthesis of sulfonates
Precursors for 8F-alkyl compounds of general Formula I are e.g. tosylates, brosylates, nosylates, mesylates, triflates, nonaflates etc. which can be synthesized from the respective hydroxyl compounds according to methods known in the art (J.
March, Advanced Organic Chemistry, 4th ed. 1992, John Wiley & Sons, pp 352ff). An additional method is described in Examples 5 and 7 and comprises the synthesis by suitable bis(tosylates) and the like, e.g. TsO-(CH2)n-OTs. Other precursors for 8F-alkyl compounds of general Formula I are e.g. iodides and bromides and the like whose conversion to the respective fluorides is also known in the art (J. March, see above).
18F Fluorination
The radiosynthesis of the 18F labeled compounds of the invention can be accomplished in multiple ways using known methods described in the literature and databases in reach of the person skilled in the art.
More specifically, compounds of the invention according to the general Formulae II and III can be synthesized starting from I as outlined in Scheme 1 1 . Such nucleophilic fluorinations are known to the person skilled in the art and also described in the literature, for reviews and cited references within see e.g. Cai ef a/., Eur. J. Org. Chem., 2008. 2853; Ametamey ef a/., Chem. Rev., 2008, 108, 1501 , Miller ef a/., Angew. Chem. Int. Ed. 2008. 47, 8998.
Figure imgf000134_0001
Scheme 11 Synthesis of 18F-labeled compounds of Formula III (R1, R2.
R3, R3, R4, LG. A, Q, X, Z) are describe above)
Additionally, compounds of the invention according to the general Formulae II and III wherein L is "alkylene-O" or "alkylene-NH" can be obtained by conversion of compounds of Formula IV, wherein Z is OH or Nhb with a 8F labeled building block (e.g. 8F-alkylene-LG). Such 18F labeled building block can be bromo-[18F]fluoro- methane (18F-CH2-Br). 18F-CH2-Br can be synthesized by reacting di-bromo- methane with a [18F]fluoride source.
19F Fluorination
In a similar way, as described for 18F labeled compounds of Formulae II and III. 19F- derivatives of Formula V can be obtained by nucleophilc fluorination of molecules of Formula I with subsequential removal of protecting groups in one or more steps affording 19F compounds of Formula VI (Scheme 12).
Alternatively, 19F substituted compounds of the invention according to the general formulae V and VI can be approached starting from intermediates H-1 by fluorination of the hydroxy I group by methods known to the person skilled in the art to compounds of Formula V.
Additionally, compounds of the invention according to the general Formulae V and VI wherein L is "alkylene-O" or "alkylene-NH" can be obtained by conversion of compounds of Formula IV, wherein Z is OH or NH2 with a F containing building block (e.g. F-alkylene-LG).
Figure imgf000136_0001
IV
Scheme 12 Synthesis of 19F-derivatives of Formula V and VI (R1, R2,
R3. R3. R4, LG. A. Q. X. Z) are describe above)
It is obvious to the person skilled in the art, that starting form different building blocks (such as L- or D-amino acid derivatives or L/D mixtures) a variety of different stereoisomers can be synthesized following the general description above and in the examples.
HPLC METHODS
Preparative HPLC, if not stated otherwise, was performed on HPLC devices comprising a Labomatic HD-3000 HPLC gradient pump, a 125 x 30 mm Chromatorex C-18 column, a standard UV detector, and Labomatic Labocol Vario-2000 fraction collector. Flow rate was typically 150 mL/minute. and total gradient time in the range of 7 minutes.
Method A:
Column: Chromatorex C-18 10 μηι, 125 x 30 mm
Eluents: A: 0.1 % HCOOH in water, B: eCN,
Gradient: A 35% / B 65 % > B 100%
Method B:
Column: Chromatorex C-18 10 μιη, 125 x 30 mm
Eluents: A: 0.1 % HCOOH in water, B: MeCN,
Gradient: A 90% I B 10 % » A 50 % / B 50 %
Method C:
Column: Chromatorex C-18 10 μιη. 125 x 30 mm
Eluents: A: 0.1 % HCOOH in water, B: MeCN,
Gradient: A 70% / B 30 %→ A 30 % / B 70 %
Method D:
Column: Chromatorex C-18 10 μιτι, 125 x 30 mm
Eluents: A: 0.1 % HCOOH in water, B: MeCN,
Gradient: A 60% / B 40 %→ A 20 % / B 80 %
Method E:
Column: Chromatorex C-18 10 μιτι, 125 x 30 mm
Eluents: A: 0.1 % HCOOH in water, B: MeCN,
Gradient: A 75% / B 25 %→ A 99 % / B 1 %
ANALYTICAL HPLC METHODS
Analytical HPLC was used for determination of radiochemical purity of the 18F labeled derivatives. The corresponding 19F derivatives were used for confirmation of the identity. Analytical HPLC system 1 :
HPLC pump: Agilent 1200, Bin Pump SL G1315B
UV detector: Agilent 1200, DAD SL G1315C
Radioactivity detector: Raytest Gabi
Analytical HPLC system 2:
HPLC pump: Agilent 1 100, Bin Pump G1312A
UV detector: Agilent 1 100, DAD G1315B
Radioactivity detector: Raytest Gabi
Analytical HPLC method C:
Column: ACE 3 C18, 4.6 x 50 mm, 3 μητι, 100 A
Eluents: A: water + 0.1 % TFA; B: acetonitrile + 0.1 % TFA
Flow: 2 mL/min
Gradient: 0:00-01 :00 min 5% B, 01 :00-04:00 min 5-95% B, 04:00-04:20 min 95-100% B, 04:20-05:50 min 100% B, 05:00-06:00 min 100-5% B, 06:00-07:00 min 5% B.
Analytical HPLC method D:
Column: Chromolith SpeedROD, 50*4.6mm, RP-18e, Merck
Eluents: A: 0.01 M Na2HP04 (pH 7.4): B: acetonitrile
Flow: 2 mL/min
Gradient: 00:00-02:00 min 0% B, 02:00-07:00 min 0-95% B, 07:00-07:20 min 95-100% B, 07:20-08:50 min 100% B, 08:50-09:00 min 100-0% B, 09:00-10:50 min 0% B Analytical HPLC method E:
Column: ACE 3 C18, 4.6 x 50 mm, 3 μιτι, 100 A
Eluents: A: water + 0.1 % TFA; B: acetonitrile + 0.1 % TFA
Flow: 2 mL/min
Gradient: 00:00-02:00 min 5% B, 02:00-07:00 min 5-95% B, 07:00-07:20 min 95-100% B, 07:20-08:50 min 100% B, 08:50-09:00 min 100-5% B, 09:00-10:50 min 5% B
Analytical HPLC method F:
Column: Hypercarb, 100 x 4.6 mm, 7 μιτι, Thermo Scientific
Eluents: A: water + 0.1 % TFA; B: acetonitrile + 0.1 % TFA
Flow: 2 mL/min Gradient: 00:00-07:00 min 5-95% B, 07:00-07:20 min 95-100% B, 07:20-08:50 min 100% B, 08:50-09:00 min 100-5% B, 09:00-12:00 min 5% B
Analytical HPLC method G - Pre-column Derivatization method:
Coiumn: Luna 5μ C18, 250 x 4.6 mm, 5 μιτι, Phenomenex
Eluents: A Na2HPGvbuffer 0,04 M pH 7.8; B: acetonitrile/methanol/water 45/45/10 Flow: 1.5 mL/min
Gradient: 00:00-30:00 min 10-50% B, 30:00-31 :00 min 50-100% B, 31 :00-34:00 min 100% B, 34:00-35:00 min 100-10% B, 35:00-37:00 min 10% B
Pre-column derivatization: 20 pL sample + 20 pL borate buffer (Agilent) + 20 pL OPA- reagent (Agilent)
Analytical HPLC method H:
Column: ACE 3 C18, 4.6 x 50 mm, 3 pm, 100 A
Eluents: A: water + 0.1 % TFA; B: acetonitrile + 0.1 % TFA
Flow: 2 mL/min
Gradient: 00:00-10:00 min 5-30% B, 10:00-10:50 min 30-100% B, 10:50-12:00 min 100% B, 12:00-12:50 min 100-5% B, 12:50-14:00 min 5% B Analytical HPLC method I:
Column: ACE 3 C18, 4.6 x 50 mm, 3 pm, 100 A
Eluents: A: water + 0.1 % TFA; B: acetonitrile + 0.1 % TFA
Flow: 2 mL/min
Gradient: 00:00-07:00 min 5-95% B, 07:00-08:00 min 95-100% B, 08:00-08:80 min 100% B, 08:80-09:00 min 100-5% B, 09:00-1 1 :00 min 5% B
CHIRAL ANALYTICAL HPLC METHODS
If not stated otherwise, chiral analytical HPLC was performed at a flow rate of 1.0 mL/min and with the column at room temperature. Analyte loading typically is 5 pL of a 1.0 mg/mL solution in a suitable solvent. For further details, the reader is referred to the individual methods.
Chiral HPLC method c1 :
System: Waters: Alliance 2695, DAD 996, ESA: Corona
Column: Chiralpak AD-H 5pm 150x4.6 mm Eluent: hexane / ethanol 90:10 isocratic
Detection: DAD 210 nm
Chiral HPLC method c2:
System: Waters: Alliance 2695, DAD 996, ESA: Corona
Column: Chiralpak IA 5μιη 150x4.6 mm
Eluent: hexane / ethanol 95:5 isocratic
Detection: DAD 210 nm Chiral HPLC method c3:
System: Dionex: Pump 680, ASI 100, Knauer: UV-Detector K-2501
Column: Chiralpak AD-H 5μιτι 150x4.6 mm
Eluent: hexane / isopropanol 80:20 + 0.1 % HCOOH isocratic
Detection: UV 210 nm
Chiral HPLC method c4:
System: Dionex: Pump 680, ASI 100, Waters: UV-Detector 2487
Column: Chiralpak AD-H 5μιτι 150x4.6 mm
Eluent: hexane / isopropanol 85:15 + 0.1 % diethylamine isocratic
Detection: DAD 220 nm
Chiral HPLC method c5:
System: Dionex: Pump 680, ASI 100, Waters: UV-Detector 2487
Column: Chiralpak AD-H 5pm 150x4.6 mm
Eluent: hexane / isopropanol 80:20 + 0.1 % diethylamine isocratic
Detection: DAD 220 nm
The phrase "Water (pH 2)" as used in the examples below, is refering to a diluted hydrochloric acid of pH 2.
EXAMPLES
CHEMISTRY EXAMPLES
Example 1
(4SH-r4^2-FluoroethoxYltenzYil^^ acid
Figure imgf000141_0001
1 l]-W-(fert-butoxycarbonyl)-L-glutamate
Figure imgf000141_0002
6.0 g (16.7 mmol) of di-fert-butyl Boc-glutamate (Journal of Peptide Research (2001 ), 58, 338) were dissolved in 50 mL of tetrahydrofuran and cooled to -70°C. 36.7 mL (36.7 mmol) of a 1 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise over a period of 90 min at this temperature and the mixture was stirred at - 70°C for another 2 hours. 13.88 g (50 mmol) of 4-(benzyloxy)benzyl bromide (Helvetica Chimica Acta, 2002, 85, 3422) in 40 mL of tetrahydrofuran were then added dropwise, and after 2 h at this temperature, the cooling bath was removed and 90 mL of 2N aqueous hydrochloric acid and 500 mL of dichloromethane were added. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 3.44 g (37.1 %)
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= = 1 .31 (s, 9H), 1 .44-1.57 (m, 18H), 1.87 (t, 2H), 2.61 (m, 1 H), 2.78-2.81 (m, 2H), 4.14-4.20 (m, 1 H), 4.89 (d, 1 H), 5.04 (s, 2H), 6.87 (d, 2H), 7.08 (d, 2H), 7.37-7,44 (m, 5H).
ESI+ m/z 556 (M+H).
b) Di-fert-butyl (4S)-W-{(ert-butoxycarbonyl)-4-(4-hydroxybenzyl)-L-glutamate
Figure imgf000142_0001
3.3 g (5.94 mmol) of di-fert-butyl (4S)-4-[4-(benzyloxy)benzyl]- V-(ferf-butoxycarbonyl)-L- glutamate were dissolved in 200 ml_ of methanol and under argon atmosphere palladium (10% on charcoal) was added and the suspension hydrogenated overnight at room temperature. The reaction mixture was filtered, the solvent evaporated and the residue was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 2.07 g (74.9%) 1H-NMR (600 MHz, CHLOROFORM-d): δ [ppm]= = 1 .33 (s, 9H), 1 .44 (m, 18H), 1 .88 (t, 2H), 2.61 (m, 1 H), 2.74-2.83 (m, 2H), 4.15-4.21 (m, 1 H), 4.89 (d, 1 H), 5.08 (s, 1 H), 6.72 (d, 2H), 7.03 (d, 2H).
ESI+ m/z 466 (M+H).
c) (4S)-4-[4-{2-Fluoroethoxy)benzyl]-L-glutamic acid
Figure imgf000142_0002
1
To 315 mg (0.68 mmol) of di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-(4-hydroxy- benzyl)-L-glutamate in 30 ml_ A/.N-dimethylformamide were added 206 mg (1 .5 mmol) of powdered potassium carbonate and 104 mg (0.81 mmol) of 1 -bromo-2-fluoroethane and the resulting suspension was stirred for 5h at 60°C and overnight at room temperature. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in ethyl acetate and water. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. Di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-[4-(2- fluoroethoxy)benzyl]-L-glutamate was obtained as crude product (1 10 mg, 32,6%) and deprotected without further purification: 3 mL of trifluoro acetic acid were added to the oily residue and the solution was stirred for 2 days at room temperature. The excess of trifluoro acetic acid was evaporated and the residue was taken up three times in tetrahydrofuran and then evaporated. The resulting oil was chromatographed on C-18 reversed phase silica gel using a water/acetonitrile gradient, the appropriate fractions were combined and concentrated.
Yield: 25 mg (41 .8%)
1H-N R (400 MHz, DIMETHYLFORMAMIDE-d7): δ [ppm]= 1 .90-1 .94 (m, 2H), 2.54- 2.56 (m, 1 H), 3.00-3.03 (m, 2H), 3.82-3.87 (m, 1 H), 4.22-4.31 (m, 2H), 4.80 (dt, 2H), 6.90 (d, 2H), 7.17 (d, 2H).
ESI+ m/z 300 (M+H).
Example 2
DHterf-butyl (4S)-<V^{grt-butoxvcarbonylW4- Jto^
Figure imgf000143_0001
Di-teri-butyl (4S)-/V-(ierf-butoxycarbonyl)-4-(4-hydroxybenzyl)-L-glutamate (90 mg, 0.19 mmol), 1 ,2-ethanediol-bis(4-methylbenzenesulfonate) (358 mg, 0.97 mmol), and caesium carbonate (189 mg, 0.580 mmol) were dissolved in 9 mL N,N- dimethylformamide and the solution was stirred at room temperature for 16h. Another 200 mg of caesium carbonate were added and the mixture stirred for additional 4h. The reaction was then poured into 1 N aqueous hydrochloric acid (50 mL) and extracted with dichioromethane (3 x 75 mL). The combined organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 90 mg (70.1 %) 1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .31 (s, 9H), 1 .42 - 1 .43 (m, 9H), 1 .43 (s, 9H), 1 .85 (t, 2H), 2.44 (s, 3H), 2.59 (quin, 1 H), 2.70 - 2.85 (m, 2H), 4.06 - 4.12 (m, 3H), 4.29 - 4.37 (m, 2H), 4.88 (d, 1 H), 6.63 - 6.71 (m, 2H), 7.01 - 7.08 (m, 2H), 7.30 - 7.37 (m, 2H), 7.77 - 7.84 (m, 2H).
ES1+ m/z 664.6 (M+H).
Example 3
18FlFluoroethoxv)benzvll-L-qlutamic acid
Figure imgf000144_0001
[18F]-1
[18F]Fluoride (3138 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)- 4-{4-[2- (tosyloxy)ethoxy]benzyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 13 min. The crude product was diluted with water (pH 2) up to 30 mL and passed through two preconditioned Strata-X-C cartridges (Phenomenex). The cartridges were washed with 50 mL water (pH 2) and 50 mL ethanol. 782 MBq (43% d.c.) 4-[4-(2- [ 8F]Fluoroethoxy)benzyl]-L-glutamic acid ([18F]-1 ) were eluted with 5 mL phosphate buffer (7 g Na2HPO.r2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >95% (tR = 3.5 min, analytical HPLC method D).
Example 4
^ ή ^ ί^!^^)^^ --≠»^≠^ acid
Figure imgf000145_0001
a) Di-fert-butyl (4S)-W-(fert-butoxycarbonyl)-4-[4-{3-fluoropropoxy)benzyl]-L-
Figure imgf000145_0002
To 93 mg (0.20 mmol) of di-fert-butyl (4S)- V-(fe/f-butoxycarbonyl)-4-(4-hydroxybenzyl)- L-glutamate (Example 1 b) in 9 ml_ Λ/,/V-dimethylformamide were added 60.7 mg (0.44 mmol) of powdered potassium carbonate and 45 mg (0.24 mmol) of 1 -iodo-3- fluoropropane (ABCR GmbH, Germany) and the resulting suspension was stirred for 5h at 60°C and overnight at room temperature. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in ethyl acetate and water. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. The crude product obtained in this manner was chromatographed on silica gel using a dichloromethane/methanol gradient, and the appropriate fractions were combined and concentrated.
Yield: 96 mg (91 .4%)
1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .33 (s, 9H), 1 .44 (s, 18H), 1 .87 (m, 2H), 2.09-2.22 (m, 2H), 2.56-2.66 (m, 1 H), 2.80 (d, 2H), 4.06 (t, 2H), 4.18 (m, 1 H), 4.64 (m, 2H), 4.87 (d, 1 H), 6.80 (d, 2H), 7.08 (d, 2H).
ESI+ m/z 526 (M+H).
b) (4S)-4-[4-(3-Fluoropropoxy)benzyl]-L-glutamic acid
Figure imgf000146_0001
4
60 mg (0.1 1 mmol) of di-ferf-buty! (4S)- V-(ferf-butoxycarbonyl)-4-[4-(3-fluoropropoxy)- benzyl]-L-glutamate were taken up in 2 mL of trifluoro acetic acid and 1 mL of methoxybenzene and stirred overnight at room temperature. The excess of trifluoro acetic acid was evaporated and the residue was taken up three times in tetrahydrofuran and then evaporated. The resulting oil was chromatographed on C-18 reversed phase silica gel using a water/acetonitrile gradient, the appropriate fractions were combined and concentrated.
Yield: 15 mg (40.7%)
1H-NMR (500 MHz, DMSO-d6): δ [ppm]= 1 .56-1.71 (m, 2H), 2.01 -2.15 (m, 2H), 2.44- 2.49 (m, 2H), 2.66-2.75 (m, 2H), 2.90 (m, 2H), 3.32-3.38 (m, 1 H), 4.02 (t, 2H), 4.59 (m, 2H), 6.83 (d, 2H), 7.08 (d, 2H). ESI+ m/z 314 (M+H).
Example 5
Figure imgf000146_0002
To 100 mg (0.22 mmol) of di-fert-butyl (4S)-/V-(ferf-butoxycarbonyl)-4-(4-hydroxy- benzyi)-L-glutamate (Example 1 b) in 10 mL /V.W-dimethylformamide were added 210 mg (0.64 mmol) of cesium carbonate and 413 mg (1 .07 mmol) of 1 ,3-propanediol di-p- toluenesulfonate (Aldrich) and the resulting suspension was stirred overnight at room temperature. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in dichloromethane and 1 M hydrochloric acid. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 87 mg (56.8%)
1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .33 (s, 9H), 1 .44 (d, 18H), 1 .87 (t, 2H), 2.10 (m, 2H), 2.40 (s, 3H), 2.57-2.65 (m, 1 H), 2.74-2.84 (m, 2H), 3.92 (t, 2H), 4.15- 4.26 (m, 3H), 4.88 (d, 1 H), 6.67 (d, 2H), 7.05 (d, 2H), 7.27 (d, 2H), 7.76 (d, 2H).
ESI+ m/z 678 (M+H).
Example 6
18FlFluoropropoxv)benzvll-L-qlutamic acid
Figure imgf000147_0001
[18F]Fluoride (3055 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-fert-butyl (4S)-/V-(ferf-butoxycarbonyl)-4-{4-[3- (tosyloxy)propoxy]benzyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water (pH 2) up to 30 mL and passed a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 40 mL ethanol. 1216 MBq (63% d.c.) 4-[4-(3-[ 8F]fluoropropoxy)benzyl]-L-glutamic acid ([18F]-4) were eluted with 5 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >95% (tR = 3.9 min, analytical HPLC method D). Example 7
Di-ferf-butyl (4S)-A/-(fef toxycarbonyl)-4-<4
nzyl)-L-glutamate
Figure imgf000148_0001
5.0 g (13.9 mmol) of di-fert-butyl Boc-glutamate (Journal of Peptide Research (2001 ), 58, 338) were dissolved in 30 mL of tetrahydrofuran and cooled to -70°C. 30.6 mL (30.6 mmol) of a 1 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise over a period of 85 min at this temperature and the mixture was stirred at - 70°C for another 2 hours. 9.0 g (41 .7 mmol) of 4-nitrobenzyl bromide in 30 mL of tetrahydrofuran were then added dropwise, and after 1 .5 h at this temperature, the cooling bath was removed and 100 mL of 2N aqueous hydrochloric acid and 450 mL of dichloromethane were added. The organic phase was separated off, washed with water (3 x 150 mL), dried over sodium sulfate and filtered, and the filtrate was concentrated. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 2.56 g (33.5%)
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm] = 1 .29 (s, 9H), 1 .43-1 .52 (m, 18H), 1.87-1 .97 (m, 2H), 2.60-2.71 (m, 1 H), 2.86-2.97 (m, 1 H), 3.04-3.15 (m, 1 H), 4.24-4.33 (m, 1 H), 4.96 (d, 1 H), 7.39(d, 2H), 8.14 (d, 2H).
ESI* m/z 495 (M+H). -fert-butyl (4S)-4-<4-aminobenzyl)-N-(fert-butoxycarbonyl)-L-glutamate
Figure imgf000149_0001
To 2.35 g (4.3 mmol) di-fert-butyl (4S)-A/-(fert-butoxycarbonyl)-4-(4-nitrobenzyl)-L- glutamate in 50 ml_ methanol and under argon atmosphere palladium (10% on charcoal) was added and the suspension hydrogenated overnight at room temperature. The reaction mixture was filtered, the solvent evaporated and the residue was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .84 g (90.8%)
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm] = 1 .34 (s, 9H), 1 .39-1 .49 (m, 18H), 1.80-1.91 (m, 2H), 2.55-2.64 (m, 1 H), 2.69-2.78 (m, H), 3.57 (br. s, 2H), 4.1 1 -4.21 (m, 1 H), 4.86 (d, 1 H), 6.58 (d, 2H), 6.96 (d, 2H).
ESI+ m/z 465 (M+H).
c) Di-fert-butyl (4S)-W-(fert-butoxycarbonyl)-4-(4-{[3-(tosyloxy)propyl]amino}-
Figure imgf000149_0002
To 230 mg (0.5 mmol) of di-fert-butyl (4S)-4-(4-aminobenzyl)-N-(fert-butoxycarbonyl)-L- glutamate in 12 ml_ W.W-dimethylformamide were added 138 mg (1 .0 mmol) of potassium carbonate and 385 mg (1 .0 mmol) of 1 ,3-propanediol di-p-toluenesulfonate (Aid rich) and the resulting suspension was heated for 1 h at 100°C in a microwave oven. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in dichloromethane. The crude product obtained in this manner was chromatographed on a Biotage® SNAP cartridge KP-NH using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 6 mg (1 .8%) 1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 (s, 9H), 1 .44 (s, 18H), 1 .83-1 .94 (m, 5H), 2.45 (s, 3H), 2.57-2.60 (m, 1 H), 2.72-2.75 (m, 2H), 3.16-3.20 (m, 2H), 4.12- 4.16 (m, 3H), 4.86 (d, 1 H), 6.43 (d, 2H), 6.95 (d, 2H), 7.33 (d, 2H), 7.80 (d, 2H).
ESI+ m/z 677 (M+H).
Example 8
i!d (3ii8F1F!u0ropro
Figure imgf000150_0001
[«F]-8
[18F]Fluoride (2900 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-fert-butyl (4S)- V-(ferf-butoxycarbonyl)-4-(4-{[3- (tosyloxy)propyl]amino}benzyl)-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water up to 5 mL and purified by semi-preparative HPLC (ACE 5 C18, 250 x 10 mm; 5-30% acetonitrile in water + 0.1 % TFA over 20 min). The product fraction at « 10:50 min was collected, diluted upt to 20 mL with water pH2 and passed trough a SCX cartridge (Strata-X-C 200mg by Phenomenex). The cartridge was washed with ethanol (20 mL) and the product was eluted with 5 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 I H20). 67 MBq (4% d.c.) 4-{4-[(3- [18FJfluoropropyl)amino]benzyl}-L-glutamic acid ([ 8F]-8) were obtained. Radiochemical purity was determined to be >95% (tR = 1 .7 min, analytical HPLC method C). Example 9
Figure imgf000151_0001
-<4-Bromophenyl)propan-1 -ol
Figure imgf000151_0002
3-(4-bromophenyl)propionic acid (Aldrich) (12.25 g, 53.48 mmol) was dissolved in tetrahydrofuran (100 mL) and the solution was slowly added to lithium aluminum hydride (1 .22 g, 32.09 mmol) in tetrahydrofuran (100 mL). The reaction was stirred for 3h, then 150 mL 1 N aqueous sodium hydrogen carbonate was added, the mixture was extracted with ethyl acetate (3 x 150 mL) and the organic phases were dried over magnesium sulphate and concentrated in vacuo. The crude product was used without purification.
Yield: 5.77 g (50.2%)
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .59 (br. s., 1 H), 1 .79 - 1 .96 (m, 2H), 2.57 - 2.74 (m, 2H), 3.67 (t, 2H), 7.02 - 7.15 (m, 2H), 7.36 - 7.47 (m, 2H). pyl ether
Figure imgf000151_0003
3-(4-bromophenyl)propan-1 -ol (5.77 g, 26.83 mmol) was mixed with dichloromethane (30 mL) and water (30 mL), and benzyl bromide (6.88 g, 40.24 mmol), tetra-n- butylammonium hydrogen sulfate (0.46 g, 1 .34 mmol), and sodium hydroxide (5.37 g, 134.17 mmol) were added subsequently. The mixture was stirred overnight, extracted several times with dichloromethane and the combined organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated. Yield: 3.59 g (43.9%)
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .80 - 2.04 (m, 2H), 2.69 (t, 2H), 3.48 (t, 2H). 4.51 (s, 2H), 7.06 (d, 2H), 7.32 - 7.47 (m, 7H). -[3-{Benzyloxy)propyl]benzaldehyde
Figure imgf000152_0001
To a solution of benzyl 3-(4-bromophenyl)propyl ether (3.59 g, 1 1 .77 mmol) in tetrahydrofuran (32 mL) at -75 "C under an argon atmosphere was added n-butyllithium (1 .6 M in hexane, 8.83 mL). The solution was stirred for 15min, and N.N- dimethylformamide (1 .09 mL, 14.13 mmol) was added dropwise. The reaction was stirred for another 30min and then warmed to room temperature, quenched with aqueous ammonium chloride solution, extracted with fert-butyl methyl ether and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .86 g (62.1 %) 1H-N R (400MHz, CHLOROFORM-d): δ [ppm]= 1 .89 - 2.04 (m, 2H), 2.75 - 2.90 (m, 2H), 3.50 (t, 2H), 4.52 (s, 2H), 7.29 - 7.43 (m, 7H), 7.80 (d, 2H), 9.98 (s, 1 H). -[3-{Benzyloxy)propyl] benzyl alcohol
Figure imgf000152_0002
To a solution of 4-[3-(benzyloxy)propyl]benzaldehyde (1 .86 g, 7.31 mmol) in ethanol (28 mL), sodium borohydride (83 mg, 2.19 mmol) was slowly added at room temperature. The mixture was stirred for 1 h. Water (50 mL) was added, and the mixture was extracted with ethyl acetate (3 x 50 mL), dried over magnesium sulfate and concentrated in vacuo. The crude product was used without purification.
Yield: 2.12 g (1 13.2%) 1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .67 (br. s, 1 H), 1 .87 - 2.02 (m, 2H), 2.66 - 2.81 (m, 2H). 3.50 (t, 2H), 4.52 (s, 2H), 4.67 (s, 2H), 7.13 - 7.23 (m. 2H), 7.27 - 7.34 (m, 3H), 7.34 - 7.42 (m, 4H). yl]propyl ether
Figure imgf000153_0001
{4-[3-(benzyloxy)propyl]benzyl alcohol (1 .86 g, 7.31 mmol) was dissolved in 82 mL dichloromethane. The solution was cooled to 0 °C. 3.25 g (12.41 mmol) triphenyl phosphine and 4.1 1 g (12.41 mmol) carbon tetrabromide were added to the solution. The ice bath was removed and the reaction was stirred for 1 h. The solution was concentrated in vacuo, to the residue was added iert-butyl methyl ether (100 mL) and the mixture was stirred at -20 °C for 30min. The mixture was filtrated and the filtrate was concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .75 g (75%)
1H-N R (400MHz, CHLOROFORM-d): δ [ppm]= 1 .86 - 2.01 (m, 2H), 2.73 (t, 2H), 3.50 (t, 2H), 4.50 (s, 2H), 4.52 (s, 2H), 7.16 (d, 2H), 7.28 - 7.42 (m, 7H).
f) Di-fert-butyl (4S)-4-{4-[3-{benzyloxy)propyl]benzyl}-A -{fert-butoxycarbonyl)-L- glutamate
Figure imgf000153_0002
To a solution of 1 .08 g (3.38 mmol) di-fert-butyl /V-(fert-butoxycarbonyl)-L-glutamate in tetrahydrofuran (18 mL) at -78 °C, lithium 1 , 1 , 1 .3,3,3-hexamethyldisilazan-2-ide (1 .0 M in tetrahydrofuran, 6.20 mL) was added dropwise. The solution was stirred for 2h, then 1-[3-(benzyloxy)propyl]-4-(bromomethyl)benzene (1 .01 g, 2.82 mmol) dissolved in 5 mL tetrahydrofuran were added slowly. The reaction was stirred for additional 2h and then quenched by the addition of 10 mL of 2 N aqueous hydrogen chloride. The mixture was warmed to room temperature poured into 10 mL 1 N aqueous hydrogen chloride and extracted with dichloromethane (3 x 30 mL). The organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .36 g (67.3%)
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .31 (s, 9H), 1 .44 (s, 9H), 1 .45 (s, 9H), 1.82 - 1 .98 (m, 4H), 2.60 - 2.75 (m, 3H), 2.77 - 2.89 (m, 2H), 3.49 (t, 2H), 4.07 - 4.27 (m, 1 H), 4.51 (s, 2H), 4.89 (d, 1 H), 7.08 (s, 4H), 7.28 - 7.45 (m, 5H).
ESI+ m/z 598.5 (M+H).
g) Di-fert-butyl (4S)-W-{fert-butoxycarbonyl)-4-[4-{3-hydroxypropyl)benzyl]-L-
Figure imgf000154_0001
To a solution of 690 mg (1 .15 mmol) di-iert-butyl (4S)-4-{4-[3-(benzyloxy)propyl]benzyl}- A/-(fert-butoxycarbonyl)-L-glutamate in 17 mL of methanol, palladium (10% on charcoal) was added and the suspension was stirred overnight at room temperature under a hydrogen atmosphere. The mixture was filtered over celite, and the solvent was evaporated. The remaining material was used without purification.
Yield: 563 mg (96.1 %)
1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .31 (s, 9H), 1 .44 (s, 9H), 1 .45 (s, 9H), 1.81 - 1 .95 (m, 4H), 2.62 - 2.73 (m, 3H), 2.83 (dd, 2H), 3.67 (t, 2H), 4.04 - 4.28 (m, 1 H), 4.89 (d, 1 H), 7.09 (s, 4H).
ESI* m/z 508.4 (M+H). )-4-[4-{3-fluoropropyl)benzyl]-L-glutamate
Figure imgf000155_0001
Di-ferf-butyl (4S)-/V-(fert-butoxycarbonyl)-4-{4-[3-(tosyloxy)propyl]benzyl}-L-glutamate (see Example 10) (100 mg, 0.15 mmol) was dissolved in 1 ml acetonitrile, and tetra-n- butylammonium tetra-(tert-butyl alcohol)-coordinated fluoride (Angew. C em. 2008, 120, 8532-8534) (169 mg, 0.30 mmol) were added. The mixture was stirred at 70 °C for 2h. Another 169 mg of the fluoride source was added and the reaction stirred for further 1 .5h at 70 °C. After cooling to room temperature, the mixture was poured into water (10 ml) and extracted with iert-butyl methyl ether (3 x 10 ml). The organic phases were dried over magnesium sulfate and concentrated in vacuo. The residue was purified on a reversed phase (RP-18) column with an acetonitrile/water gradient. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield 50 mg (64.9%) (mixture of diastereomers)
ESI+ m/z 510.6 (M+H) -glutamic acid
Figure imgf000155_0002
Di-fe/f-butyl A/-(iert-butoxycarbonyl)-4-[4-(3-fluoropropyl)benzyl]glutamate (50 mg, 0.10 mmol) was dissolved in 3 ml trifluoroacetic acid and stirred at room temperature for 1 d. Then, 5 ml toluene were added and the solution was concentrated in vacuo. The product was purified by preparative HPLC. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 9.8 mg (32.3%) (mixture of diastereomers) 1H-NMR (400MHz, DMSO-d6): δ [ppm]= 1 .64 - 1 .83 (m, 1 .66H), 1 .84 - 2.00 (m, 2H), 2.03 - 2.12 (m, 0.31 H), 2.54 - 2.67 (m, 2.61 H), 2.77 - 2.96 (m, 2.36H), 3.57 (dd, 0.8H), 3.61 - 3.68 (m, 0.4H), 4.44 (dt, 2H, J (H,F) = 47.4Hz), 7.00 - 7.25 (m, 4H). ESI+ m/z 298.4 (M+H).
Example 10
Figure imgf000156_0001
Di-feri-butyl (4S)-/V-(ierf-buioxycarbonyl)-4-[4-(3-hydroxypropyi)benzyl]-L-glutamate (514 mg, 1 .01 mmol) was dissolved in pyridine (25 mL) and p-toluenesulfonic anhydride (Aldrich) (661 mg, 2.03 mmol) was slowly added at 0 °C. The reaction was stirred for 2h, then poured into 25 mL 1 N aqueous hydrogen chloride. The mixture was extracted with fert-butyl methyl ether (3 x 50 mL), the organic phases washed with saturated aqueous sodium hydrogen carbonate, dried over sodium sulfate and concentrated in vacuo. The crude product was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated. The product was repurified on a reversed phase (RP-18) HPLC column with an acetonitrile/water gradient. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 179 mg (26.7%)
1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .30 (s, 9H), 1 .44 (s, 9H), 1 .45 (s, 9H), 1.81 - 1 .99 (m, 4H), 2.47 (s, 3H), 2.56 - 2.69 (m, 3H), 2.73 - 2.91 (m, 2H), 4.03 (t, 2H), 4.1 1 - 4.32 (m, 1 H), 4.89 (d, 1 H), 6.97 (d, 2H), 7.05 (d, 2H), 7.36 (d, 2H), 7.80 (d, 2H). ESI+ m/z 662.6 (M+H). Example 11
18F1Fluoropropvl)benzyn-L-qlutamic acid
Figure imgf000157_0001
[18F]-9
[18F]Fluoride (2837 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA. Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of tosylate di-fert-butyl (4S)-/V-(ferf-butoxycarbonyl)-4-{4-[3- (tosyloxy)propyl]benzyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt. 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water (pH 2) up to 30 mL and passed a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 40 mL ethanol. 940 MBq (50% d.c.) 4-[4-(3-[ 8F]fluoropropyl)benzyl]-L-glutamic acid ([18F]-9) were eluted with 5 mL phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >95% (tR = 2.9 min, analytical HPLC method E).
Example 12
benzvllhexanedioic acid
Figure imgf000157_0002
12 a) fert-Butyl (2S)-2-[(fert-butoxycarbonyl)amino]-4-oxobutanoate
Figure imgf000158_0001
To a solution of 1 .10 g (4.0 mmol) fert-butyl /V-(fert-butoxycarbonyl)-L-homoserinate (prepared according to J. Org. Chem. 1988, 53, 1900-1903) in dichloromethane (50 mL) was added pyridine (0.97 mL, 12.0 mmol), followed by 2.55 g Dess Martin periodinane (6.0 mmol), at room temperature. The mixture was stirred 90 min at room temperature prior to being diluted with ethyl acetate (40 mL). The mixture was washed with 10 % aqueous sodium thiosulfate, saturated aqueous sodium bicarbonate and brine. The organic layer was dried over sodium sulfate and then evaporated. The crude product (1 .09 g, quantitative yield) was used immediately without further purification.
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .45 (s br, 9 H), 1 .46 (s, 9 H), 2.88 - 3.10 (m, 2 H), 4.42 - 4.55 (m, 1 H), 5.27 - 5.46 (m, 1 H), 9.74 (s, 1 H). yl]-2-{dimethoxyphosphoryl)propanoate
Figure imgf000158_0002
To a suspension of 1 .71 g sodium hydride (50 % in oil, 35.7 mmol) in anhydrous tetrahydrofuran (100 mL) was added a solution of 8.0 g ierf-butyl P,P- dimethylphosphonoacetate (35.7 mmol) in anhydrous tetrahydrofuran (25 mL) at room temperature, and the resulting mixture was stirred for 1 h at room temperature. Subsequently, a solution of 4.95 g 4-benzyloxybenzyl bromide (17.8 mmol; prepared according to Helv. Chim. Acta, 2002, 85, 3422) in tetrahydrofuran (25 mL) was added, and the mixture was stirred at room temperature overnight. Saturated aqueous ammonium chloride (50 mL) was then added, the mixture was stirred for another 20 minutes at room temperature, and extracted with ethyl acetate. The organic layer was dried over magnesium sulfate and evaporated. Column chromatography over silica gel (2.5 → 50 % ethyl acetate in hexane) gave 1 .48 g (20 % yield based on 4- benzyloxybenzyl bromide) of the target compound. 1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 (s, 9 H), 3.06 - 3.22 (m, 3 H), 3.81 (s br, 3 H), 3.83 (s br, 3 H), 5.05 (s, 2 H), 6.89 (d, 2 H), 7.13 (d, 2 H), 7.29 - 7.45 (m, 5 H).
ESI+ m/z 365 (M+H-C4H8, m/z (M+H) 421 , m/z (M +NH4) 438.
c) Di-ferf-butyl (E)-{S)-2-[4-(benzyloxy)benzyl]-5-[(fert-butoxycarbonyl)amino]hex- 2-enedioate, and Di-fert-butyl (Z)-(S)-2-[4-(benzyloxy)benzyl]-5-[(fert-butoxy-
Figure imgf000159_0001
To a suspension of 169 mg of sodium hydride (60% in oil. 4.22 mmol) in anhydrous tetrahydrofuran (30 mL) was added a solution of 1 .48 g of tert-butyl 3-[4- (benzyloxy)phenyl]-2-(dimethoxyphosphoryl)propanoate (3.52 mmol) in anhydrous tetrahydrofuran (20 mL) at a temperature of 0°C. The mixture was stirred for 15 minutes at 0°C, followed by the dropwise addition of a solution of 1 .06 g of iert-butyl (2S)-2- [(fert-butoxycarbonyl)amino]-4-oxobutanoate (3.87 mmol) in anhydrous tetrahydrofuran (10 mL), also at a temperature of 0°C. The mixture was stirred for another 90 minutes at 0°C before the reaction was stopped by the addition of saturated aqueous sodium bicarbonate. The mixture was extracted with ethyl acetate (3x), the combined organic layers were dried over sodium sulfate and then evaporated. The residue was purified by column chromatography on silica gel (2.5→ 35 % ethyl acetate in hexane) to give 1 .60 g of the target compound (80 % yield) as a mixture of double bond isomers.
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 - 1 .54 (m, 27 H), 2.56 - 2.90 (m, 2 H), 3.43 - 3.66 (m, 2 H), 4.22 (q br, 1 H, minor isomer), 4.35 (q br. 1 H, major isomer), 5.03 (s, 2 H, minor isomer), 5.05 (s, 2 H, major isomer), 5.13 (d br, 1 H, major isomer), 5.37 (d br, 1 H, minor isomer), 5.71 - 5.80 (m, 1 H, minor isomer), 6.67 - 6.77 (m, 1 H, major isomer), 6.84 - 6.93 (m, 2 H), 7.03- 7.12 (m, 2 H), 7.28 - 7.47 (m, 5 H).
ESI+ m/z 568 (M+H).
d) Di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-<4-hydroxybenzyl)hexane-
Figure imgf000160_0001
To a solution of 1 .50 g of di-fert-butyl ( )-(S)-2-[4-(benzyloxy)benzyl]-5-[(iert- butoxycarbonyl)amino]hex-2-enedioate and di-fert-butyl (Z)-(S)-2-[4-(benzyloxy)benzyl]- 5-[(fert-butoxycarbonyl)amino]hex-2-enedioate (mixture of double bond isomers, 2.64 mmol) in methanol (50 ml_) was added 750 mg of a 10% palladium on carbon catalyst, and the mixture was stirred under an atmosphere of hydrogen for 1 .5 hours. The catalyst was filtered off, and the filtrate was evaporated. Column chromatography of the residue on silica gel (2.5→ 35 % ethyl acetate in hexane) gave 920 mg of the target compound (73 % yield).
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .41 - 1 .48 (m, 18 H), 1 .52 - 1 .68 (m, 3 H), 1 .72 - 1.86 (m, 1 H), 2.41 - 2.67 (m, 2 H), 2.74 - 2.86 (m, 1 H), 4.12 - 4.25 (m, 1 H), 5.06 (t br, 1 H), 5.29 - 5.38 (s br, 1 H), 6.72 (d, 2 H), 6.98 - 7.07 (m, 2 H),
ESI+ m/z 480 (M+H). chiral HPLC (method c5): tn = 4.2 and 5.2 minutes (two peaks, baseline separation of C-5 epimers).
The compound synthesized in Example 12d was also prepared via an alternative procedure. It was shown by chiral HPLC that the stereocenter stemming from the L- homoserine synthon used is being retained during the sequence (see also examples 15a-15d which were prepared starting from the corresponding D-homoserine synthon). o-2-[(fert-butoxycarbonyl)amino]butanoate
Figure imgf000161_0001
A mixture of 5.00 g (18.2 mmol) iert-butyl A/-(fert-butoxycarbonyl)-L-homoserinate (prepared according to J. Org. Chem. 1988, 53, 1900-1903), 3.23 g W-bromo succinimide (18.2 mmol), and 6.16 g polymer bound triphenylphosphine (loading approx. 3 mmol/g, approx. 18.5 mmol) in dichloromethane (60 mL) was stirred overnight at room temperature. All solids were removed by filtration, and the filtrate was concentrated in vacuo. The residue was purified by column chromatography on silica gel (2.5→ 25 % ethyl acetate in hexane) to give 2.56 g of the title compound (38 % yield).
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .46 (s, 9 H), 1 .49 (s, 9 H); 2.10 - 2.26 (m app sext, 1 H), 2.30 - 2.46 (m, 1 H), 3.36 - 3.50 (m, 2 H), 4.21 - 4.34 (m, 1 H), 5.10 (s br, 1 H). ESI+ m/z 338, 340 (M+H, Br isotopes well reflected).
f) Di-fert-butyl (5S)-2-{benzyloxycarbonyl)-5-[(fert-butoxycarbonyl)amino]hexane- dioate
Figure imgf000161_0002
To a suspension of 296 mg sodium hydride (60 % in oil, 7.39 mmol) in /V,/V-dimethyl formamide (40 mL) was added a solution of 2.04 g benzyl /ert-butyl malonate (commercial, 8.13 mmol) in /V.A/-dimethylformamide (20 mL) at room temperature. The mixture was stirred for one hour at room temperature before a solution of 2.50 g tert- butyl (2S)-4-bromo-2-[(fert-butoxycarbonyl)amino]butanoate (7.39 mmol) in N.N- dimethylformamide (20 mL) was added. The mixture was stirred overnight at room temperature and was then evaporated in vacuo. The residue was purified by column chromatography on silica gel (2.5→ 20 % ethyl acetate in hexane) to give the title compound in approx. 90% purity (2.56 g, 61 % purity adjusted yield).
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .39 + 1 .40 (2 s, 9 H, diastereomers), 1.44 (s, 9 H), 1 .46 + 1.47 (2 s, 9 H, diastereomers), 1 .59 - 2.00 (m, 4 H), 3.27 - 3.37 (m, 1 H), 4.19 (s br, 1 H), 5.05 (s br, 1 H), 5.14 (app. d, 1 H), 5.21 (app. dd, 1 H), 7.31 - 7.40
(m, 5 H).
ESI+ m/z 508 (M+H). chiral HPLC (method c1 ): \R = 8.5 minutes (broad peak with shoulder, C-1 epimers not fully resolved). The (4R)-analogue prepared from the respective D-homoserine synthon shows separate C-1 epimers at 4.1 and 4.8 minutes (see example 15b).
g) Di-fert-butyl (5S)-2-[4-(benzyloxy)benzyl]-2-(benzyloxycarbonyl)-5-[(fert-butoxy-
Figure imgf000162_0001
To a solution of 1 .00 g di-fert-butyl (5S)-2-(benzyloxycarbonyl)-5-[(ferf-butoxycarbonyl)- amino]hexanedioate (1 .97 mmol) in A/.W-dimethyl formamide (20 mL) was added under argon atmosphere 71 mg of sodium hydride (60 % in oil, 1 .77 mmol). The resulting mixture was stirred at room temperature for 30 minutes. A solution of 546 mg 4- benzyloxybenzyl bromide (1 .97 mmol; prepared according to Helv. Chim. Acta, 2002, 85, 3422) in Λ/./V-dimethylformamide (10 mL) was added, and the mixture was stirred at 60 °C for one hour. After cooling to room temperature, the mixture was concentrated in vacuo and partitioned between water and ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate and evaporated. The residue was purified by column chromatography on silica gel (2.5→ 20 % ethyl acetate in hexane) to give 1 .22 g of the title compound (88 % yield).
1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 (s, 9 H, minor diastereomer), 1.35 (s, 9 H, major diastereomer), 1 .41 (s, 9 H, minor diastereomer), 1 .42 (s, 9 H, major diastereomer), 1 .44 (s, 9 H, minor diastereomer), 1 .45 (s, 9 H, major diastereomer), 1.60 - 1 .91 (m, 4 H), 3.08 (dd, 1 H), 3.19 (dd, 1 H), 4.15 - 4.21 (m, 1 H), 4.99 - 5.07 (m,
3 H), 5.09 - 5.19 (m, 2 H), 6.79 - 6.85 (m, 2 H), 6.93 - 6.99 (m, 2 H), 7.31 - 7.45 (m, 10 H). ESI+ m/z 704 (M+H). chiral HPLC (method c2): tR - 6.1 minutes single peak, C-4 epimers not resolved). The (1 f?)-analogue prepared from the respective D-homoserine synthon shows separate C-
4 epimers at 4.0 and 4.7 minutes (see example 15c).
h) (5S)-2-{ferf-Butoxycarbonyl)-5-[(ferf-butoxycarbonyl)amino]-2-{4- butyI ester
Figure imgf000163_0001
To a solution of 1 .07 g di-fert-butyl (5S)-2-[4-(benzyloxy)benzyl]-2-(benzyloxycarbonyl)- 5-[(fert-butoxycarbonyl)amino]hexanedioate (1 .52 mmol) in methanol (20 mL) was added a 10% palladium on carbon hydrogenation catalyst (100 mg) at room temperature. The suspension was stirred overnight at room temperature under an atmosphere of hydrogen. The catalyst was removed by filtration and all volatiles were removed in vacuo. The crude product (800 mg, quantitative yield) was used in the next step without further purification.
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .41 - 1 .53 (m, 27 H), 1 .60 - 2.06 (m, 4 H), 3.03 (dd, 1 H), 3.26 (d br, 1 H), 4.07 - 4.27 (m, 1 H), 5.15 (app dd, 1 H), 6.68 - 6.76 (m, 2 H), 6.96 - 7.05 (m, 2 H).
ESI+ m/z 524 (M+H). chiral HPLC (method c3): tR = 4.8 minutes, C-2 epimers are not resolved. The (5R)- analogue prepared from the respective D-homo-serine synthon shows separate C-2 epimers at 3.0 and 3.7 minutes (see example 15d).
i) Di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-(4-hydroxybenzyl)hexane-
Figure imgf000164_0001
ent ca w t
A solution of 730 mg (5S)-2-(iert-butoxycarbonyl)-5-[(fert-butoxycarbonyl)amino]-2-(4- hydroxybenzyl)hexanedioic acid 6-iert-butyl ester (1 .39 mmol) and 290 mg 4-N.N- dimethylaminopyridine (2.37 mmol) in tetrahydrofuran (10 mL) was heated under reflux for 18 hours. Since the turnover was only approx. 75 % then, and to drive the reaction to completion, the mixture was evaporated, the residue dissolved in 1 ,4-dioxane, and heated under reflux for another 2 hours after which turnover was complete. The mixture was evaporated and the residue was purified by column chromatography on silica gel (2.5 → 35 % ethyl acetate in hexane), to give 590 mg (88 % yield) of the target compound featuring an HNMR spectrum in line with the HNMR data for example 12d. 1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .42 - 1 .47 (m, 18 H), 1 .51 - 1 .67 (m, 3 H), 1 .75 - 1.84 (m, 1 H), 2.43 - 2.51 (m, 1 H, major diastereomer), 2.51 - 2.59 (m, 1 H, minor diastereomer), 2.59 - 2.66 (m, 1 H), 2.76 - 2.85 (m, 1 H), 4.14 - 4.23 (m, 1 H), 4.92 - 4.97 (m, 1 H), 5.04 (app t br, 1 H), 6.73 (d, 2 H), 6.99 - 7.05 (m, 2 H).
ESI+ m/z 480 (M+H). chiral HPLC (method c4): tR = 6.4 and 8.5 minutes (two peaks, baseline separation of C-5 epimers). The (2f?)-analogue prepared from the respective D-homoserine synthon shows baseline separated C-5 epimers at 4.7 and 7.9 minutes (see example 15e).
j) Di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[4-(2-fluoroethoxy)benzyl]- hexanedioate
Figure imgf000165_0001
To a solution of 54 mg 1 -fluoro-2-iodoethane (0.31 mmol) in /V./V-dimethy formamide (10 mL) was subsequently added 101 mg potassium carbonate (0.73 mmol), followed by 100 mg di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-(4-hydroxybenzyl)- hexanedioate (from example 12d; 0.21 mmol), and the resulting mixture was stirred for 4 h at room temperature. The mixture was then partitioned between water and ethyl acetate, the aqueous layer was then extracted with ethyl acetate again. The combined organic layers were washed with brine, dried over sodium sulfate, and evaporated. The residue was purified by preparative HPLC, method A to give 85 mg (62 % purity adjusted yield) of the target compound in approx. 80% purity.
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm] = 1 .35 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .41 - 1 .47 (m, 18 H), 1.52 - 1 .67 (m, 3 H), 1 .73 - 1.85 (m, 1 H), 2.43 - 2.68 (m, 2 H), 2.78 - 2.88 (m, 1 H), 4.12 - 4.26 (m, 3 H), 4.67 - 4.84 (m, 2 H), 4.98 - 5.09 (m, 1 H), 6.83 (d, 2 H), 7.06 - 7.13 (m, 2 H).
ESI* m/z 526 (M+H). roethoxy)benzyl]hexanedioic acid
Figure imgf000166_0001
12
To a solution of 80 mg of di-fert-butyl (2S)-2-[(ferf-butoxycarbonyl)amino]-5-[4-(2- fluoroethoxy)benzyl]hexanedioate (0.15 mmol) in anisol (1 .0 mL) was added trifluoroacetic acid (2.0 mL), and the resulting mixture was stirred overnight at room temperature. All volatiies were removed in vacuo and the residue was purified by preparative HPLC, method B, to give 30 mg of the target compound as white lyophilisate (62 % yield).
1H-NMR (400 MHz, d6-DMSO): δ [ppm] = 1 .25 - 1 .91 (m, 4 H), 2.26 - 2.38 (m, 1 H), 2.53 - 2.78 (m, 2 H), 3.04 - 3.19 (m, 1 H), 4.12 - 4.25 (m, 2 H), 4.63 - 4.80 (m, 2 H), 6.83 - 6.88 (m, 2 H), 7.06 - 7.13 (m, 2 H). OH and NH signals not considered due to proton exchange / overlap with broad water signal.
ESI* m/z 314 (M+H).
Example 13
Di-tert-butyl (2S)-2-r(ferf-butoxvcarbonyl)aminol-5-{4-r2-(tosvloxv)ethoxvlbenzvl)- hexanedioate
Figure imgf000167_0001
To a solution of 541 mg 1 .2-ethanediol di-p-toluenesulfonate (1 .46 mmol) in N.N- dimethylformamide (10 mL) was subsequently added 238 mg cesium carbonate (0.73 mmol). followed by 100 mg di-ferf-butyl (2S)-2-[(tert-butoxycarbonyl)amino]-5-(4- hydroxybenzyl)hexanedioate (from example 12d; 0.21 mmol). and the resulting mixture was stirred overnight at room temperature. The mixture was then concentrated in vacuo and partitioned between water and dichloromethane. The organic layer was washed with brine, dried over sodium sulfate, and evaporated. Combined purification by column chromatography over silica gel (10 ♦ 80 % ethyl acetate in hexane) and prep. HPLC (Method A) gave 71 mg (49 % yield) of the desired tosylate in very high purity.
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm] = 1 .34 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .41 - 1 .49 (m, 18 H), 1 .51 - 1 .68 (m, 3 H), 1 .72 - 1.87 (m, 1 H), 2.40 - 2.68 (m, 2 H), 2.46 (s, 3 H), 2.74 - 2.87 (m, 1 H), 4.08 - 4.24 (m, 3 H), 4.32 - 4.40 (m, 2 H), 5.03 (t br, 1 H), 6.69 (d, 2 H), 7.00 - 7.10 (m, 2 H), 7.35 (d, 2 H), 7.83 (d, 2 H).
ESI+ m/z 622 (M+H-C.,H8, m/z (M+H) 678.
Example 14
(2S)-2-Amino-5-r4-(2-r18Flfluoroethoxv)benzyllhexanedioic acid
Figure imgf000168_0001
[18F]-12
[18F]Fluoride (3728 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of tosylate di-fert-butyl (2S)-2-[(terf-butoxycarbonyl)aminoj- 5-{4-[2-(tosyloxy)ethoxy]benzyl}hexanedioate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt. 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water (pH 2) up to 30 mL and passed through a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 45 mL ethanol. 1704 MBq (50% d.c.) (2S)-2-Amino-5-[4-(2- [18F]fluoroethoxy)benzyl]hexanedioic acid ([18F]-12) were eluted with 5 mL phosphate buffer (7 g Na2HPO.r2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >95% (tR = 3.0 min, analytical HPLC method E).
Example 15
Figure imgf000168_0002
a) fert-Butyl (2 ?)-4-bromo-2-[(fert-butoxycarbonyl)amino]butanoate
Figure imgf000169_0001
A mixture of 1 .39 g (5.05 mmol) fert-butyl /V-(fert-butoxycarbonyl)-D-homoserinate (prepared according to J. Org. C em. 1988, 53, 1900-1903), 899 mg W-bromo succinimide (5.05 mmol), and 1 .68 g polymer bound triphenylphosphine (loading approx. 3 mmol/g, approx. 5.0 mmol) in dichloromethane (17 mL) was stirred overnight at room temperature. All solids were removed by filtration, and the filtrate was concentrated in vacuo. The residue was purified by column chromatography on silica gel (2.5→ 25 % ethyl acetate in hexane) to give 580 mg of the title compound (34 % yield).
1H-N R (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .46 (s, 9 H), 1 .49 (s, 9 H); 2.1 1 - 2.24 (m app sext, 1 H), 2.31 - 2.45 (m, 1 H), 3.37 - 3.49 (m, 2 H), 4.21 - 4.33 (m, 1 H), 5.10 (s br, 1 H). b) Di-ferf-butyl (5R)-2-{benzyloxycarbonyl)-5-[(fert-butoxycarbonyl)amino]hexane-
Figure imgf000169_0002
To a suspension of 66 mg sodium hydride (60 % in oil, 1 .66 mmol) in /V./V-dimethyl- formamide (10 mL) was added a solution of 456 mg benzyl fert-butyl maionate (commercial, 1 .82 mmol) in W.W-dimethylformamide (5 mL) at room temperature. The mixture was stirred for one hour at room temperature before a solution of 560 mg tert- butyl (2R)-4-bromo-2-[(fert-butoxycarbonyl)amino]butanoate (1 .66 mmol) in N.N- dimethylformamide (5 mL) was added. The mixture was stirred for 60 hours at room temperature and was then evaporated in vacuo. The residue was purified by column chromatography on silica gel (1 .5→ 20 % ethyl acetate in hexane) to give the title compound (390 mg, 46 % yield). 1H-NMR (300 MHz. CHLOROFORM-d): δ [ppm]= 1 .39 + 1 .40 (2 s, 9 H, diastereomers),
1.42 - 1 .49 (m, 18 H), 1 .59 - 2.00 (m, 4 H), 3.26 - 3.37 (m, 1 H), 4.19 (s br, 1 H), 5.05 (s br, 1 H), 5.14 (app. d, 1 H), 5.21 (app. dd, 1 H), 7.31 - 7.41 (m, 5 H). ESI+ m/z 508 (M+H). chiral HPLC (method c1 ): tn = 4.1 and 4.8 minutes (two peaks, baseline separation of C-1 epimers). The (4S)-analogue prepared from the respective L-homo-serine synthon shows the C-1 epimers as one broad peak at 8.5 minutes (see example 12f).
c) Di-fert-butyl (5 ?)-2-[4-(benzyloxy)benzyl]-2-(benzyloxycarbonyl)-5-[(fert- te
Figure imgf000170_0001
To a solution of 340 mg di-fert-butyl (5R)-2-[4-(benzyloxy)benzyl]-2- (benzyloxycarbonyl)-5-[(fert-butoxycarbonyl)amino]hexanedioate (0.67 mmol) in N,N- dimethylformamide (7 mL) was added under argon atmosphere 24 mg of sodium hydride (60 % in oil, 0.60 mmol). The resulting mixture was stirred at room temperature for 60 minutes. A solution of 186 mg 4-benzyloxybenzyl bromide (0.67 mmol; prepared according to Helv. Chim. Acta, 2002, 85, 3422) in /V./V-dimethylformamide (3 mL) was added, and the mixture was stirred at 60 °C for one hour. After cooling to room temperature, the mixture was concentrated in vacuo and partitioned between water and ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate and evaporated. The residue was purified by column chromatography on silica gel using an ethyl acetate / hexane gradient to give 470 mg of the title compound (quantitative yield). 1H-NMR (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 (s, 9 H, minor diastereomer), 1.35 (s, 9 H, major diastereomer), 1 .41 (s, 9 H, minor diastereomer), 1 .42 (s, 9 H, major diastereomer), 1 .44 (s, 9 H, minor diastereomer), 1 .45 (s, 9 H, major diastereomer), 1.60 - 1 .91 (m, 4 H), 3.08 (dd, 1 H), 3.19 (dd, 1 H), 4.15 - 4.21 (m, 1 H), 4.99 - 5.07 (m, 3 H), 5.09 - 5.19 (m, 2 H), 6.79 - 6.85 (m, 2 H), 6.93 - 6.99 (m, 2 H), 7.31 - 7.45 (m, 10 H).
ESI+ m/z 704 (M+H). chiral HPLC (method c2): t = 4.0 and 4.7 minutes, two peaks, baseline separation of C-4 epimers). The (I S)-analogue prepared from the respective L-homo-serine synthon shows unresolved C-4 epimers at 6.1 minutes (see example 12g).
d) (5R)-6-ferf-Butoxy-2-(ferf-butoxycarbonyl)-5-[(fert-butoxycarbonyl)amino]-2-(4- d
Figure imgf000171_0001
To a solution of 370 mg di-fert-butyl (5R)-2-[4-(benzyloxy)benzyl]-2- (benzyloxycarbonyl)-5-[(fert-butoxycarbonyl)amino]hexanedioate (0.53 mmol) in methanol (10 mL) was added a 10% palladium on carbon hydrogenation catalyst (50 mg) at room temperature. The suspension was stirred for 2.5 hours at room temperature under an atmosphere of hydrogen. The catalyst was removed by filtration and all volatiles were removed in vacuo. The crude product (273 mg, 99% yield) was used in the next step without further purification.
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .43 - 1 .52 (m, 27 H), 1 .58 - 2.14 (m, 4 H), 3.03 (dd, 1 H), 3.25 (d br, 1 H), 4.07 - 4.27 (m, 1 H), 5.12 (app d br, 1 H, minor diastereomer), 5.19 (app d br, 1 H, major diastereomer), 6.68 - 6.75 (m, 2 H), 6.96 - 7.04 (m, 2 H).
ESI+ m/z 524 (M+H). chiral HPLC (method c3): tR = 3.0 and 3.7 minutes, two peaks, baseline separation of C-2 epimers). The (5S)-analogue prepared from the respective L-homoserine synthon shows unresolved C-2 epimers at 4.8 minutes (see example 12h).
e) Di-fert-butyl (2 ?)-2-[(fert-butoxycarbonyl)amino]-5-{4-hydroxybenzyl)hexane-
Figure imgf000172_0001
A solution of 237 mg (5R)-6-iert-butoxy-2-(iert-butoxycarbonyl)-5-[(ferf-butoxycarbonyl)- amino]-2-(4-hydroxybenzyl)-6-oxohexanoic acid (0.45 mmol) and 94 mg 4-N.N- dimethylaminopyridine (0.77 mmol) in 1 .4-dioxane (5 mL) was heated under reflux for 2 hours. The residue was purified by column chromatography on silica gel using an ethyl acetate / hexane gradient to give 141 mg of the title compound (65 % yield).
1H-N R (500 MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .42 - 1 .47 (m, 18 H), 1 .51 - 1 .67 (m, 3 H), 1 .74 - 1.84 (m, 1 H), 2.43 - 2.51 (m, 1 H, major diastereomer), 2.51 - 2.59 (m, 1 H, minor diastereomer), 2.59 - 2.66 (m, 1 H), 2.76 - 2.84 (m, 1 H), 4.14 - 4.23 (m, 1 H), 4.96 - 5.00 (m, 1 H), 5.04 (app t br, 1 H), 6.73 (d, 2 H), 6.99 - 7.05 (m, 2 H).
ESI+ m/z 480 (M+H). chiral HPLC (method c4): tR = 4.7 and 7.9 minutes (two peaks, baseline separation of C-5 epimers). The (2S)-analogue prepared from the respective L-homoserine synthon shows baseline separated C-5 epimers at 6.4 and 8.5 minutes (see example 12i).
f) Di-fert-butyl (2/?)-2-[(fert-butoxycarbonyl)amino]-5-{4-[2-{tosyloxy)ethoxy]- benzyl}hexanedioate
Figure imgf000173_0001
To a solution of 351 mg 1 .2-ethanediol di-p-toluenesulfonate (0.95 mmol) in N.N- dimethylformamide (6.5 mL) was subsequently added 155 mg cesium carbonate (0.47 mmol), followed by 65 mg di-ferf-butyl (2R)-2-[(fert-butoxycarbonyl)amino]-5-(4- hydroxybenzyljhexanedioate (0.136 mmol), and the resulting mixture was stirred for 2.5 hours at room temperature. The mixture was then concentrated in vacuo and purified by prep. HPLC (Method A) to give 80 mg (87 % yield) of the desired tosylate.
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .34 (s, 9 H, minor diastereomer), 1.36 (s, 9 H, major diastereomer), 1 .40 - 1 .48 (m, 18 H), 1 .50 - 1 .69 (m, 3 H), 1 .72 - 1.86 (m, 1 H), 2.46 (s, 3 H), 2.42 - 2.67 (m, 2 H), 2.76 - 2.87 (m, 1 H), 4.07 - 4.24 (m, 3 H), 4.32 - 4.39 (m, 2 H), 4.97 - 5.08 (m, 1 H), 6.69 (d, 2 H), 7.00 - 7.10 (m, 2 H), 7.35 (d, 2 H), 7.83 (d, 2 H). ESI+ m/z 678 (M+H).
Example 16
(2 ?)-2-Amino-5-r4-(2-r 8Flfluoroethoxv)benzvllhexanedioic acid
Figure imgf000173_0002
[ 8F]-16
[18F]Fluoride (570 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of tosylate di-fert-butyl (2R)-2-[(tert-butoxycarbonyl)aminoj- 5-{4-[2-(tosyloxy)ethoxy]benzyl}hexanedioate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt, 2 HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water (pH 2) up to 30 mL and passed through a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. 207 MBq (58% d.c.) (2R)-2-Amino-5-[4-(2- [18F]fluoroethoxy)benzyl]hexanedioic acid ([18F]-16) were eluted with 5 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >98% (tR = 2.8 min, analytical HPLC method C).
Example 17
Di-terf-butvl (4/?)-A/-(ferf-butoxvcarbonvH-4-^r5-(2-fluoroethoxv)pyridin-2-
Figure imgf000174_0001
-{Benzyloxy)-2- bromomethyl)pyridine
Figure imgf000174_0002
A mixture of 540 mg (2.51 mmol) 5-benzyloxy-2-pyridinemethanol (prepared according to J. Med. Chem. 1977, 20, 1258-1262), 536 mg /V-bromo succinimide (3.01 mmol), and 1.2 g polymer bound triphenylphosphine (loading approx. 3 mmol/g, approx. 3.3 mmol) in dichloromethane (40 mL) was stirred overnight at room temperature. All solids were removed by filtration, and the filtrate was washed with aqueous sodium bicarbonate and water, and then concentrated in vacuo. The crude product (540 mg of a slightly pink solid, 79 % crude yield) was used without further purification.
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 4.55 (s, 2 H), 5.12 (s, 2 H), 7.24 (dd, 1 H), 7.31 - 7.47 (m, 6 H), 8.35 (d, 1 H). ESI+ m/z 278, 280 (M+H, Br isotopes well reflected).
b) Di-fert-butyl (4R)-4-{[5-(benzyloxy)pyridin-2-yl]methyl}-/V-(fert-butoxycarbonyl)-
Figure imgf000175_0001
540 mg (1 .50 mmol) of di-fert-butyl Boc-glutamate (prepared according to J. Peptide Res. 2001 , 58, 338) were dissolved in 6 mL of tetrahydrofuran and cooled to -75°C. 3.45 mL (3.45 mmol) of a 1 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise and the mixture was stirred at -75°C for another 60 minutes. 460 mg (1 .65 mmol) of 5-(benzyloxy)-2-(bromomethyl)pyridine in 5 mL of tetrahydrofuran were then added dropwise, and after stirring 2 hours at -75"C, 3.45 mL of 2N aqueous hydrochloric acid were added, and after stirring another 30 minutes at - 75"C, the cooling bath was removed and the mixture was allowed to warm up to room temperature. The mixture was partitioned between dichloromethane and aqueous sodium bicarbonate, and the organic layer was dried over magnesium sulfate and evaporated. The crude residue was purified by column chromatography on silica gel (ethyl acetate in hexane 0 %→ 100 %) to give 610 mg of the desired compound as yellowish oil (66 % yield).
1H-N R (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .36 (s, 9 H), 1 .43 (s, 9 H), 1 .54 (s, 9 H), 1 .79 - 2.05 (m, 2 H), 2.81 - 3.09 (m, 3 H), 4.12 - 4.22 (m, 1 H), 5.05 (app d br), 5.09 (s, 2 H), 7.06 (d, 1 H), 7.17 (dd, 1 H), 7.30 - 7.46 (m, 5 H), 8.29 (d, 1 H).
ESI+ m/z 557 (M+H)
c) Di-fert-butyl (4 ?)-W-{fert-butoxycarbonyl)-4-[(5-hydroxypyridin-2-yl)methyl]-L- glutamate
Figure imgf000176_0001
To a solution of 610 mg (1 .10 mmol) of di-fert-butyl (4f?)-4-{[5-(benzyloxy)pyridin-2- yl]methyl}-N-(iert-butoxycarbonyl)-L-glutamate in methanol (35 mL) was added a 10 % palladium on charcoal catalyst (29 mg), and the resulting suspension was stirred overnight under an atmosphere of hydrogen at room temperature. The catalyst was removed by filtration, and the filtrate was evaporated to give 500 mg of the pure target compound as colorless foam (98 % yield).
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H), 1 .43 (s, 9 H), 1 .44 (s, 9 H), 1 .82 - 2.08 (m, 2 H), 2.78 - 3.07 (m, 3 H), 4.08 - 4.19 (m, 1 H), 5.13 (d br, 1 H), 5.33 (s br, OH, weak signal likely due to H/D exchange), 7.06 (d, 1 H), 7.18 (dd, 1 H), 8.19 (d. 1 H).
ESI+ m/z 467 (M+H)
d) Di-fert-butyl (4R)-/V-{fert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-
Figure imgf000176_0002
To a solution of 196 mg 1 -fluoro-2-iodoethane (1 .13 mmol) in A/./V-dimethylformamide (25 mL) was subsequently added 363 mg potassium carbonate (2.63 mmol), followed by 350 mg di-fert-butyl (4R)- V-(terf-butoxycarbonyl)-4-[(5-hydroxypyridin-2-yl)methyl]-L- glutamate 0.75 mmol), and the resulting mixture was stirred for 4 h at room temperature. The mixture was then partitioned between water and dichloromethane, and the organic layer was washed with brine, dried over magnesium sulfate, and evaporated. Purification of the crude product by preparative HPLC (method A) gave 313 mg of the target compound (81 % yield). 1H-NMR (600 MHz, CHLOROFORM-d): δ [ppm]= 1 .37 (s, 9 H), 1 .42 (s, 9 H), 1 .44 (s, 9 H), 1 .85 - 1 .89 (m. 1 H), 1 .98 (dt, 1 H). 2.87 - 2.96 (m, 2 H), 3.01 - 3.04 (m, 1 H), 4.13 - 4.17 (m, 1 H), 4.21 - 4.22 (m, 1 H), 4.25 - 4.27 (m, 1 H), 4.71 - 4.80 (m. 2 H). 5.05 (d, 1 H), 7.08 (d, 1 H), 7.15 (dd, 1 H), 8.24 (d. 1 H).
ESI+ m/z 513 (M+H)
Example 17-e
(4 ?)^-{f5-{2-fluoroethoxY)pYridin-2-YllmethYl}-L-qlutamic acid
Figure imgf000177_0001
(4R)-4-{[5-(2-fluoroeihoxy)pyridin-2-yl]meihyl}-L-glutamic acid (17) can be synthesized by deprotection of di-ferf-butyl (4R)-/V-(ferf-butoxycarbonyl)-4-{[5-(2- fluoroethoxy)pyridin-2-yl]methyl}-L-glutamate (e.g. by treatment with TFA).
Example 18
Di-tert-butvl (4S)-A/-(ferf-butoxvcarbonvl)-4-r4-((2-phenvl-5-r(tosvloxv)methvll- 1.3-
Figure imgf000177_0002
To 466 mg (1 .0 mmol) of di-fert-butyl (4S)-/V-(ferf-butoxycarbonyl)-4-(4-hydroxybenzyl)- L-giutamate in 12 ml_ /V.W-dimethylformamide were added 138 mg (1 .0 mmol) of potassium carbonate and 533 mg (1 .0 mmol) of (2-phenyl-1 ,3-dioxane-5,5- diyl)bis(methylene) bis(4-methylbenzenesulfonate) (Heterocycles 34. (1992), 739), and the resulting suspension was heated for 2h at 100°C in a microwave oven. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in ethyl acetate and water. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. The residue was chromatographed on silica gel using a dichloromethane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 23 mg (28%) 1H-N R (400 MHz, CHLOROFORM-d): δ [ppm]= 7.77 (d, 2H), 7.28-7.38 (m, 5H), 7.24 (d, 2H), 7.08 (d, 2H), 6.69 (d, 2H), 5.40 (s, 1 H), 4.90 (br. d, 1 H), 4.49 (s, 2H), 4.14-4.26 (m), 4.14 (d, 2H), 3.93 (d, 2H), 3.71 (s, 2H), 2.82 (br. d, 2H), 2.56-2.67 (m, 1 H), 2.38 (s, 3H), 1 .88 (t, 2H), 1 .46 (s, 9H), 1 .45 (s, 9H), 1 .36 (s, 9H). ESI+ m/z 826 (IVT ).
Example 19
4^f3-f4-{3-FluoroproRyl)phenYl]propYlJbL-qlutamic acid
Figure imgf000178_0001
butoxycarbonyl)-L-glutamate
Figure imgf000178_0002
To a solution of 719 mg (2.00 mmol) di-ferf-butyl /V-(ferf-butoxycarbonyl)-L-glutamate in tetrahydrofuran (12 mL) at -78 °C, lithium 1 , 1 .1 ,3,3.3-hexamethyldisilazan-2-ide (1 .0 M in tetrahydrofuran, 4.40 mL) was added dropwise. The solution was stirred for 30min, then allyl bromide (0.52 mL, 6.00 mmol) was added dropwise. The reaction was stirred at -78 °C overnight and then quenched at -10 °C by the addition of 10 mL of 2 N aqueous hydrogen chloride. The mixture was warmed to room temperature poured into 10 mL 1 N aqueous hydrogen chloride and extracted with dichloromethane (3 x 30 mL). The organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 673 mg (84.2%)
1H NMR (300 MHz, CHLOROFORM-d) δ ppm 1 .32-1 .58 (m, 27H) 1 .81 -1 .92 (m, 2H) 2.25-2.39 (m, 2H) 2.40-2.48 (m, 1 H), 4.10-4.18 (m, 1 H) 4.85-4.92 (d, 1 H) 5.02-5.1 1 (m, 2H) 5.68-5.77 (m, 1 H)
ESI+ m/z 400.2 (M+H). -(4-lodophenyl)propan-1 -ol
Figure imgf000179_0001
3-(4-iodophenyl)propanoic acid (Atlantic Research Chemicals Ltd.) (2.76 g, 10.00 mmol) were dissolved In tetrahydrofuran (100 mL) and added slowly to a suspension of lithium aluminium hydride (0.23 g, 6.00 mmol) in 100 mL tetrahydrofuran. The reaction was stirred for 3h, then 1 N aqueous sodium hydrogen carbonate (150 mL) were added slowly and the resulting mixture was extracted with ethyl acetate (3 x 400 mL), the organic extracts were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .30 g (49.8%)
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .88 (m, 2H), 2.62 - 2.72 (m, 2H), 3.64 - 3.70 (m, 2H), 6.97 (d, 2H), 7.61 (d, 2H).
ESI+ m/z 263.2 (M+H).
c) Di-fert-butyl (4S)-W-(fert-butoxycarbonyl)-4-{(E)-3-[4-<3-hydroxypropyl)phenyl]- prop-2-en-1 -yl}-L-glutamate
Figure imgf000180_0001
To a solution of di-fert-butyl (4S)-4-allyl-/V-(iert-butoxycarbonyl)-L-glutamate (940 mg, 2.53 mmol) in 5 mL acetonitrile under an argon atmosphere was added 3-(4- iodophenyl)propan-1 -ol (740 mg, 2.82 mmol), triethylamine (394 μΙ, 2.82 mmol), and palladium(l l) acetate (106 mg, 0.47 mmol). The mixture was stirred in a pressure tube at 80 °C for 2h. After cooling to room temperature, the solvent was removed under reduced pressure and the crude material was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 316 mg (25.2%)
1H-N R (300MHz, CHLOROFORM-d): δ [ppm]= 1 .43 - 1 .47 (m, 27H), 1 .82 - 1 .97 (m, 4H), 2.49 (m, 3H), 2.69 (m, 2H), 3.69 (m, 2H), 4.10 - 4.29 (m, 1 H), 4.90 (d, 1 H), 6.00 - 6.16 (m, 1 H), 6.40 (d, 1 H), 7.13 (d, 2H), 7.24 (d, 2H, partially overlayed by chloroform signal).
ESI+ m/z 534.5 (M+H).
d) Di-fert-butyl (4S)-/V-<ferf-butoxycarbonyl)-4-{3-[4-{3-hydroxypropyl)phenyl]-
Figure imgf000180_0002
To a solution of 316 mg (0.59 mmol) di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-{(E)-3- [4-(3-hydroxypropyl)phenyl]prop-2-en-1 -yl}-L-glutamate in 29 mL of methanol, palladium (10% on charcoal, 126 mg) was added and the suspension was stirred overnight at room temperature under a hydrogen atmosphere. The mixture was filtered over celite, and the solvent was evaporated. The remaining material was used without purification. Yield: 163 mg (51 .4%) ESI+ m/z 536.3 (M+H).
e) Di-tert-butyl N-(tert-butoxycarbonyl)-4-{3-[4-{3-fluoropropyl)phenyl]propyl}-L-
Figure imgf000181_0001
Di-fert-butyl (4S)-/V-(iert-butoxycarbonyl)-4-(3-{4-[3-(tosyloxy)propyl]phenyl}propyl)-L- glutamate (see Example 20) (79 mg, 0.12 mmol) was dissolved in 1 ml acetonitrile, and tetra-n-butylammonium tetra-(tert-butyl alcohol)-coordinated fluoride (Angew. Chem. 2008, 120, 8532-8534) (128 mg. 0.23 mmol) were added. The mixture was stirred at 70 °C for 1 .5h. After cooling to room temperature, the mixture was poured into water (10 ml) and extracted with tert-butylmethyl ether (3 x 10 ml). The organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude material was used in the next step without purification.
Yield: 40 mg (65.0%)
ESI+ m/z 538.6 (M+H)
Figure imgf000181_0002
Di-fert-butyl /V-(iert-butoxycarbonyl)-4-{3-[4-(3-fluoropropyl)phenyl]propyl}-L-glutamate (40 mg, 0.07 mmol) was dissolved in 3 ml trifluoroacetic acid and stirred at room temperature for 1 d. Then, 5 ml toluene were added and the solution was concentrated in vacuo. The product was purified by preparative HPLC. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 21 .4 mg (84.9%) (mixture of diastereomers) 1H-N R (400MHz, DMSO-d6): δ [ppm]= 1 .12 - 1 .20 (m, 1 H), 1 .35 - 1 .64 (m, 3.6H), 1 .66 - 1 .82 (m, 1 H), 1 .82 - 1 .99 (m, 3H), 2.07 - 2.16 (m, 0.4H), 2.52 - 2.67 (m, 4H), 3.63 (dd, 0.6H), 3.67 - 3.73 (m, 0.4H), 4.34 - 4.43 (m, 1 H), 4.43 - 4.53 (m, 1 H), 7.02 - 7.20 (m, 4H).
ESI+ m/z 326.4 (M+H).
Example 20
DHerf-butyl (jSj^jferf^toxy^^^
Figure imgf000182_0001
Di-ferf-butyl (4S)-A/-(terf-butoxycarbonyl)-4-{3-[4-(3-hydroxypropyl)phenyl]propyl}-L- glutamate (163 mg, 0.30 mmol) was dissolved in pyridine (7 mL) and p-toluenesulfonic anhydride (Aldrich) (199 mg, 0.61 mmol) was slowly added at 0 °C. The reaction was stirred for 2h, then poured into 25 mL 1 N aqueous hydrogen chloride. The mixture was extracted with ferf-butylmethyl ether (3 x 50 mL), the organic phases washed with saturated aqueous sodium hydrogen carbonate, dried over sodium sulfate and concentrated in vacuo. The crude product was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 147 mg (70.0%) H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .18 - 1 .31 (m, 1 H), 1 .42 - 1 .48 (m, 27H), 1 .57 - 1 .64 (m, 3H), 1 .79 - 1 .99 (m, 4H), 2.29 - 2.44 (m, 1 H), 2.47 (s, 3H), 2.53 - 2.65 (m, 4H), 4.04 (t, 2H), 4.07 - 4.19 (m, 1 H), 4.86 (d, 1 H), 6.96 - 7.07 (m, 4H), 7.36 (d, 2H), 7.80 (d, 2H). ESI+ m/z 690.5 (M+H).
Example 21
Di-ferf-butvl r4S)-A/- (erf-butoxvcarbonvn-4-(4-^frans-r3- tosvloxv)cvclobutvlloxv)-
Figure imgf000183_0001
a) Di-fert-butyl (4S)-4-{4-{frans-[3-(benzySoxy)cycIobytyI]oxy}benzyl)-W-(tert-
Figure imgf000183_0002
To 349 mg (0.75 mmol) of di-fert-butyl (4S)-A/-(fert-butoxycarbonyl)-4-(4-hydroxy- benzyl)-L-glutamate (Example 1 b) in 15 mL /V./V-dimethylformamide were added 138 mg (1 .0 mmol) of potassium carbonate and 332 mg (1 .0 mmol) of 2-phenyl-1 ,3-dioxan- 5-yl 4-methylbenzenesulfonate (Studii si Cercetari de Chimie (1960), 8, 187-99.) and the resulting suspension was heated for 2h at 100°C in a microwave oven. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in DMSO. The crude product obtained in this manner was chromatographed on a PrepCon3 C -18 reversed phase column using a water/acetonitrile gradient (35/65 to 0/100), and the appropriate fractions were combined and concentrated.
Yield: 43 mg (9.2%)
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .31 -1 .44 (m, 27H), 1 .58 (s, 1 H), 1 .87 (t, 2H), 2.39-2.52 (m, 4H), 2.58-2.63 (m, 1 H), 2.77-2.80 (m, 2H), 4.16-4.19 (m, 1 H), 4.31 -4.35 (m, 1 H), 4.44 (s, 2H), 4.80-4.88 (m, 2H), 6.68 (d, 2H), 7.06 (d, 2H), 7.34-7.35 (m, 5H). ESI+ m/z 626 (M+H).
b) ) Di-fert-butyl (4S)-4-{4-[frans-<3-hydroxycyclobutyl)oxy]benzyl}-N-(fert-butoxy-
Figure imgf000184_0001
43 mg (0.07 mmol) of di-fert-butyl (4S)-4-(4-{frans-[3-(benzyloxy)cyclobutyl]oxy}benzyl)- Ai-(terf-butoxycarbonyl)-L-glutamate were dissolved in 10 mL of methanol and under argon atmosphere palladium (10% on charcoal) was added and the suspension hydrogenated overnight at room temperature. The reaction mixture was filtered, the solvent evaporated and the residue was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 35 mg (95.1 %)
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .33 (s, 9H), 1 .44 (m, 18H), 1 .88 (m, 2H), 2.39-2.63 (m, 5H), 2.77-2.79 (m, 2H), 4.16-4.18 (m, 1 H), 4.84-4.86 (m, 2H), 6.68 (d, 2H), 7.06 (d, 2H).
ESI+ m/z 536 (M+H).
c) Di-fert-butyl (4S)-W-(fert-butoxycarbonyl)-4-(4-{frans-[3-(tosyloxy)cyclobutyl]-
Figure imgf000184_0002
0.233 g (0.50 mmol) Di-fert-butyl (4S)-4-{4-[frans-(3-hydroxycyclobutyl)oxy]benzyl}-/V- (ferf-butoxycarbonyl)-L-glutamate, 0.14 g (1 mmol) potassium carbonate and 0.198 g (0.50 mmol) cis-cyclobutane-1 .3-diyl bis(4-methylbenzenesulfonate) in 5 ml dimethylformamide were heated for 3.5 h at 100 °C in a microwave. The reaction mixture was diluted wit water and extracted with dichloromethane. The organic layer was dried over sodium sulfate, filtrated, the solvent was evaporated and the residue was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 24 mg (7%)
1H NMR (CHLOROFOR -d ,300MHz): δ (ppm) 7.79 (d, 2H), 7.35 (d, 2H), 7.04 (d, 2H), 6.61 (d, 2H), 4.9-5.1 1 (m, 1 H), 4.87 (br. d, 1 H), 4.73-4.83 (m, 1 H), 4.09-4.25 (m, 1 H), 2.69-2.85 (m, 2H), 2.54-2.68 (m, 3H), 2.47-2.53 (m, 2H), 2.45 (s, 3H), 1 .86 (t, 2H), 1 .44 (s, 9H), 1 .43 (s, 9H), 1 .31 (s, 9H).
ESI+ m/z 712 (M+Na).
Example 22
18F]Fluorocyclobutyl)oxy]benzyl}-L-glutamic acid
Figure imgf000185_0001
[ 8F]-22
f8F]Fluoride (3028 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-{4-[(3-{[(4- methylphenyl)sulfonyl]oxy}cyclobutyl)oxy]benzyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 140 °C for 10 min. After cooling for 5 min at rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water up to 20 mL and passed through a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 10 mL water (pH 2) and 10 mL ethanol. 319 MBq (17% d.c.) 4-{4-[(cis-3- [ 8F]fluorocyclobutyl)oxy]benzyl}-L-glutamic acid ([18F]-22) were eluted with 5 mL phosphate buffer (7 g a2HPO -2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >98% (tR = 2.9 min, analytical HPLC method C).
Example 23
i4ftH-r4-(2;£Luoroethoxy)benz¾l^^
Figure imgf000186_0001
23 l]-W-{fert-butoxycarbonyl)-D-glutamate
Figure imgf000186_0002
1.26 g (3.5 mmol) of di-ferf-butyl Boc-D-glutamate (prepared in analogy to Journal of Peptide Research (2001 ). 58, 338 from di-ferf-butyl D-glutamate) were dissolved in 15 mL of tetrahydrofuran and cooled to -70°C. 7.7 mL (7.7 mmol) of a 1 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise over a period of 30 min at this temperature and the mixture was stirred at -70°C for another 2 hours. 1 .1 1 g (4 mmol) of 4-benzyloxybenzyl bromide (Helvetica Chimica Acta, 2002, 85, 3422) in 5 mL of tetrahydrofuran were then added dropwise, and after 2 h at this temperature, the cooling bath was removed and 17.5 mL of 2N aqueous hydrochloric acid and 100 mL of dichloromethane were added. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 .0 g (36.0%) 1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .31 (s, 9H), 1 .44-1 .57 (m, 18H), 1 .87 (t, 2H), 2.61 (m, 1 H), 2.78-2.81 (m, 2H), 4.14-4.20 (m, 1 H), 4.89 (d, 1 H), 5.04 (s, 2H), 6.87 (d, 2H), 7.08 (d, 2H), 7.37-7,44 (m, 5H).
ESI+ m/z 556 (M+H). ycarbonyl)-4-{4-hydroxybenzyl)-D-glutamate
Figure imgf000187_0001
1.0 g (1 .8 mmol) of di-fert-butyl (4R)-4-[4-(benzyloxy)benzyl]-/V-(fert-butoxycarbonyl)-D- glutamate were dissolved in 35 ml_ of methanol and under argon atmosphere palladium (10% on charcoal) was added and the suspension hydrogenated overnight at room temperature. The reaction mixture was filtered, the solvent evaporated and the residue was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 0.40 g (63.6%)
1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= = 1 .33 (s, 9H), 1 .44 (m, 18H), 1 .88 (t, 2H), 2.61 (m, 1 H), 2.74-2.83 (m, 2H), 4.15-4.21 (m, 1 H), 4.90 (d, 1 H), 5.26 (s, 1 H), 6.72 (d, 2H), 7.02 (d, 2H).
ESI+ m/z 465.6 (M+H). zyl]-D-glutamic acid
Figure imgf000187_0002
To 93 mg (0.2 mmol) of di-fert-butyl (4R)- V-(fert-butoxycarbonyl)-4-(4-hydroxybenzyl)- D -glutamate in 4 ml_ /V./V-dimethylformamide were added 56 mg (0.4 mmol) of powdered potassium carbonate and 69.6 mg (0.40 mmol) of 1 -iodo-2-f!uoroethane and the resulting suspension was heated for 1 h at 100°C in a microwave oven. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in ethyl acetate and water. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. Di-iert-butyl (4R)-/V-(fert-butoxycarbonyl)-4-[4-(2-fluoroethoxy)benzyl]-D-gluta- mate was obtained as crude product (40 mg, 39, 1 %) and deprotected without further purification: 2 ml_ of trifluoro acetic acid were added to the oily residue and the solution was stirred for 2 d at room temperature. The excess of trifluoro acetic acid was evaporated and the residue was taken up three times in tetrahydrofuran and then evaporated. The resulting oil was chromatographed on C-18 reversed phase silica gel using a water/acetonitrile gradient, the appropriate fractions were combined and concentrated.
Yield: 13 mg (55.6%) H-NMR (400 MHz, DMSO-d6): δ [ppm]= 1 .60-1 .74 (m, 2H), 2.76-2.96 (m, 2H), 3.46 (m, 1 H), 4.12-4.25 (m, 2H), 4.63-4.80 (m, 2H), 6.86 (d, 2H), 7.10 (d, 2H).
ESI+ m/z 300 (M+H).
Example 24
(4 ?)-4-[4-{3-FluoropropoxY)benzYll-D-qlutamic acid
Figure imgf000188_0001
24
a) Di-fert-butyl (4 ?)-/V-{fert-butoxycarbonyl)-4-[4-{3-fluoropropoxy)benzyl]-D-
Figure imgf000188_0002
To 140 mg (0.30 mmol) of di-fert-butyl (4R)- V-(fer£-butoxycarbonyl)-4-(4-hydroxy- benzyl)-D-glutamate in 5 mL /V,/V-dimethylformamide were added 42 mg (0.3 mmol) of powdered potassium carbonate and 56 mg (0.30 mmol) of 1 -iodo-3-fluoropropane (ABCR GmbH, Germany) and the resulting suspension was heated for 2h at 100°C in a microwave oven. The reaction mixture was then filtered, the solvent evaporated and the residue was taken up in ethyl acetate and water. The organic phase was separated off, washed with water until neutral, dried over sodium sulfate and filtered, and the filtrate was concentrated in vacuo. The crude product obtained in this manner was chromatographed on silica gel using a dichloromethane/methanol gradient, and the appropriate fractions were combined and concentrated.
Yield: 60 mg (38.1 %)
1H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .33 (s, 9H), 1 .44 (s, 18H), 1 .87 (t, 2H), 2.09-2.22 (m, 2H), 2.61 (t, 1 H), 2.80 (d, 2H), 4.06 (t, 2H), 4.18 (m, 1 H), 4.54-4.58 (m, 1 H), 4.70-4.74 (m, 1 H), 4.87 (d, 1 H), 6.80 (d, 2H), 7.08 (d, 2H).
ESI+ m/z 526 (M+H). yl]-D-glutamic acid
Figure imgf000189_0001
60 mg (0.1 1 mmol) of di-terf-butyl (4R)-N-(ferf-butoxycarbonyl)-4-[4-(3-fluoropropoxy)- benzyl]-D-glutamate were taken up in 3 mL of trifluoro acetic acid and stirred overnight at room temperature. The excess of trifluoro acetic acid was evaporated and the residue was taken up three times in tetrahydrofuran and then evaporated. The resulting oil was chromatographed on C-18 reversed phase silica gel using a water/acetonitrile gradient, the appropriate fractions were combined and concentrated.
Yield: 18 mg (50.3%) 1H-NMR (400 MHz, DMSO-d6): δ [ppm]= 1 .60-1 .74 (m, 2H), 2.01 - 2.16 (m, 2H), 2.43- 2.49 (m, 2H), 2.77 - 2.94 (m, 2H), 3.47 (m, 1 H), 4.02 (t, 2H), 4.50 - 4.69 (m, 2H), 6.84 (d, 2H), 7.09 (d, 2H). ESI+ m/z 313.8 (M+H).
Example 25
llDroDvl)-L-qlutamic acid
Figure imgf000190_0001
a) Di-fert-butyl (4S)-4-{(£)-3-[4-(benzyloxy)phenyl]prop-2-en-1 -y\}-N-(tert- butoxycarbonyl)-L-glutamate
Figure imgf000190_0002
To a stirred solution of di-ierf-butyl (4S)-4-allyl-/V-(fert-butoxycarbonyl)-L-glutamate (345 mg. 0.86 mmol) in acetonitrile (5 ml) at room temperature was slowly added 1 - (benzyloxy)-4-iodobenzene (ABCR GmbH & CO. KG) (321 mg. 1 .04 mmol) in 3 ml acetonitrile, triethylamine (144μΙ, 1 .04 mmol) in 3 ml acetonitrile, and palladium(ll) acetate (Aldrich) (39 mg, 0.17 mmol). The mixture was heated in a pressure tube at 80 °C for 2h. After cooling to room temperature, the mixture was filtered and the filtrate was concentrated in vacuo. The crude material was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 1 10 mg (21 .9%)
ESI+ m/z 582.5 (M+H). b) Di-fert-butyl (4S)-N-<fert-butoxycarbonyl)-4-[3-<4-hydroxyphenyl)propyl]-L- glutamate
Figure imgf000191_0001
To a solution of 1 10 mg (0.19 mmol) di-fert-butyl (4S)-4-{4-[3-(benzyloxy)propyl]benzyl}- /V-(fert-butoxycarbonyl)-L-glutamate in 5 ml of methanol, palladium (10% on charcoal, 60 mg) was added and the suspension was stirred overnight at room temperature under a hydrogen atmosphere. The mixture was filtered over celite, and the solvent was evaporated. The remaining material was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 65 mg (69.6%)
1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .45 (m, 27H), 1 .52 - 1 .69 (m, 4H), 1.75 - 1 .96 (m, 2H), 2.28 - 2.43 (m, 1 H), 2.45 - 2.63 (m, 2H), 4.07 - 4.19 (m, 1 H), 4.88 (d, 1 H), 6.75 (d, 2H), 7.01 (d, 2H).
ESI+ m/z 494.2 (M+H).
c) Di-fert-butyl (4S)-W-(fert-butoxycarbonyl)-4-{3-[4-{2-fluoroethoxy)ph
Figure imgf000191_0002
Di-fert-butyl (4S)-A/-(fert-butoxycarbonyl)-4-[3-(4-hydroxyphenyl)propyl]-L-glutamate (80 mg, 0.16 mmol), 1 -bromo-2-fluoroethane (103 mg, 0.81 mmol), and caesium carbonate (158 mg, 0.49 mmol) were dissolved in 8 ml Λ/./V-dimethylformamide and the solution was stirred at 60 °C for 4h. The reaction was then poured into 1 N aqueous hydrochloric acid (50 ml) and extracted with dichloromethane (3 x 75 ml). The combined organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified by pHPLC on a reversed phase (RP-18) column with an acetonitrile/water gradient. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 31 mg (35.4%)
ESI+ m/z 540.6 (M+H)
d) (4S)-4-{3-[4-(2-Fluoroethoxy)phenyl]propyl}-L-glutamic acid
Figure imgf000192_0001
Di-iert-butyl (4S)-/V-(iert-butoxycarbonyl)-4-{3-[4-(2-fluoroethoxy)phenyl]propyl}-L- glutamate (31 mg, 0.06 mmol) was dissolved in 3 ml trifluoroacetic acid and stirred at room temperature for 1 d. Then, 5 ml toluene were added and the solution was concentrated in vacuo. The product was purified by preparative HPLC. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 4.5 mg (23.9%) H-N R (400MHz, DMSO-d6): δ [ppm]= 1 .32 - 1 .62 (m, 4H), 1 .69 - 1 .94 (m, 2H), 2.53 - 2.64 (m, 1 H), 3.63 (dd, 1 H), 4.19 (m, 2H, , J (H,F) = 30.4 Hz), 4.72 (m, 2H, J (H,F) = 47.7 Hz), 6.82 - 6.92 (m, 2H), 7.05 - 7.14 (m, 2H). Two hydrogen signals are apparently hidden under the DMSO solvent peak.
ESI+ m/z 328.4 (M+H).
Example 26 Di-ferf-butyl (4S)-A/-(fert-butoxYcarbonYl)-4-{3-{4-r2-{tosYloxY)ethoxYlphenYl}-
Figure imgf000193_0001
Di-tert-butyl (4S)-A/-(ierf-buioxycarbonyl)-4-[3-(4-hydroxyphenyl)propyl]-L-glutamate (240 mg, 0.49 mmol), 1 ,2-ethanediol-bis(4-methylbenzenesulfonate) (901 mg, 2.43 mmol), and caesium carbonate (475 mg, 1 .46 mmol) were dissolved in 10 ml N,N- dimethylformamide and the solution was stirred at 60 °C for 4h. The reaction was then poured into 1 N aqueous hydrochloric acid (50 ml) and extracted with dichloromethane (3 x 75 ml). The combined organic phases were dried over magnesium sulfate and concentrated in vacuo. The crude product was pre-purified by pHPLC on a reversed phase (RP-18) column with an acetonitrile/water gradient. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized. The pre-purified product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 54 mg (15.7%)
1H-N R (300MHz, CHLOROFORM-d): δ [ppm]= 1 .42 - 1 .49 (m, 27H), 1 .58 (m, 4H), 1.72 - 1 .96 (m, 2H), 2.29 - 2.42 (m, 1 H), 2.46 (s, 3H), 2.54 (m, 2H), 4.05 - 4.19 (m, 3H), 4.30 - 4.43 (m, 2H), 4.86 (d, 1 H), 6.62 - 6.77 (m, 2H), 6.96 - 7.09 (m, 2H), 7.31 - 7.41 (m, 2H), 7.77 - 7.88 (m, 2H).
ESI+ m/z 692.6 (M+H).
Example 27
(4S)-4-{3-r4-{2-r8FlFluoroethoxY)phenYllpropYl}-L-qlutamic acid
Figure imgf000194_0001
[18F]Fluoride (1353 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 ml_). 5 mg of di-fert-butyl (4S)-N-(tert-butoxycarbonyl)-4-(3-{4-[2- (tosyloxy)ethoxy]phenyl}propyl)-L-glutamate in 1 ml_ acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling for 5 min at rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with water (pH 2) up to 30 mL and passed through a preconditioned Strata-X-C cartridge (Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 45 mL ethanol. 128 MBq (14% d.c.) (4S)-4-{3-[4-(2- [ 8F]fluoroethoxy)phenyl]propyl}-L-glutamic acid ([18F]-25) were eluted with 5 mL phosphate buffer (7 g Na2HPO.«-2H20; 6 g NaCI in 1 L water). Radiochemical purity was determined to be >95% (tR = 3.1 min, analytical HPLC method C).
Example 28
Figure imgf000194_0002
28 a) Di-ferf-butyl (4f?)-4-[(5-bromopyridin-2-yl)methyl]-W-{ieri-butoxycarbonyl)-L- glutamate
Figure imgf000195_0001
To a solution of 575 mg (1 .60 mmol) di-ferf-butyl /V-(fert-butoxycarbonyl)-L-glutamate in tetrahydrofuran (4 ml) at -78 °C, lithium 1 , 1 , 1 ,3,3,3-hexamethyldisilazan-2-ide (1 .0 M in tetrahydrofuran, 3.52 ml) was added dropwise. The solution was stirred for 2h, then 5- bromo-2-(bromomethyl)pyridine (for synthesis see for example Bioorg. Med. Chem. 2008. 16, 1992-2010) (1 .08 g, 3.38 mmol) dissolved in 4 ml tetrahydrofuran were added slowly. The reaction was stirred for additional 3h and then quenched by the addition of 5 ml of 2 N aqueous hydrogen chloride. The mixture was warmed to room temperature poured into 10 ml 1 N aqueous hydrogen chloride and extracted with dichloromethane (3 x 20 ml). The organic phases were washed with 1 N aqueous sodium hydrogen carbonate solution (2 x 20 ml) and brine (20 ml), dried over sodium sulfate and concentrated in vacuo. The crude product was purified on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 233 mg (27.5%)
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .37 (s, 9H), 1 .44 (s, 9H), 1 .46 (s, 9H), 1.82 - 2.05 (m, 2H), 2.85 - 3.12 (m, 3H), 4.10 - 4.32 (m, 1 H), 5.01 (d, 1 H), 7.07 (d, 1 H), 7.70 (dd, 1 H), 8.50 - 8.65 (m, 1 H).
ESI+ m/z 529.3 (M+H).
b) Di-fert-butyl (4R)-W-{fert-bytoxycarbonyf)-4-({5-[(E)-3-{[iert- l}methyl)-L-glutamate
Figure imgf000195_0002
Di-fe/f-butyl (4R)-4-[(5-bromopyridin-2-yl)methyl]-N-(terf-butoxycarbonyl)-L-glutamate (233 mg, 0.44 mmol) was dissolved in 1 ,2-dimethoxyethane (2 ml). Terf- butyl(dimethyl){[(E}-3-(4!4.5.5-tetramethyl-1.3!2-dioxaborolan-2-yl)prop-2-en-1- yl]oxy}silane (197 mg, 0.66 mmol), palladium(ll) acetate (10 mg, 0.04 mmol), triphenylphosphine (46 mg, 0.18 mmol), and potassium carbonate (182 mg, 18.68 mmol) were added, and nitrogen was bubbled through the solution for 10 min. Then, 40 μΙ water were added and nitrogen was bubbled through the solution for additional 20 min. The solution was stirred at 80 °C for 16h. After cooling to room temperature, the mixture was filtered, the filtrate was concentrated and purified on silica gel using a hexane/ethyl acetate gradient. The appropriate fractions were combined and concentrated.
Yield: 140 mg (51.2%)
ESI+ m/z 621.3 (M+H).
c) Di-fert-butyl (4 ?)-W-(ferf-butoxycarbonyl)- -{[5-{3-{[ferf-butyl(dimethyl)silyl]-
Figure imgf000196_0001
To a solution of 140 mg (0.23 mmol) di-fert-butyl (4R)-A/-(ferf-butoxycarbonyl)-4-({5-[(E)- 3-{[iert-butyl(dimethyl)silyl]oxy}prop-1-en-1-yl]pyridin-2-yl}methyl)-L-glutamate in 8 ml of methanol, palladium (10% on charcoal, 7 mg) was added and the suspension was stirred for 3h at room temperature under a hydrogen atmosphere. The mixture was filtered over ceiite, and the solvent was evaporated. The crude material was used without further purification.
Yield: 140 mg (99.7%)
ESI+ m/z 623.5 (M+H).
d) Di-fert-butyl (4R)-/V-{fert-butoxycarbonyl)-4-{[5-(3-hydroxypropyl)pyridin-2- yl]methyl}-L-glutamate
Figure imgf000197_0001
To a solution of di-fert-butyl (4R)-N-(terf-butoxycarbonyl)-4-{[5-(3-{[ferf- butyl(dimethyl)silyl]oxy}propyl)pyridin-2-yl]methyl}-L-glutamate (140 mg, 0.23 mmol) in tetrahydrofuran (7 ml) was added acetic acid (80 μΙ, 1 .40 mmol). The solution was cooled to 0 °C, and tetra-n-butylammonium fluoride (1 M in tetrahydrofuran, 674 μΙ) was added dropwise. The cooling bath was removed and the reaction was stirred overnight, then mixed with 1 N aqueous sodium hydrogen carbonate solution (20 ml), and extracted with dichloromethane (3 x 20 ml). The organic phases were washed with brine (10 ml), dried over sodium sulfate and concentrated in vacuo. The crude material was used without further purification.
Yield: 122 mg (106.7% crude)
ESI+ m/z 509.2 (M+H).
e) Di-fert-butyl (4/?)-A/-(fert-butoxycarbonyl)-4-{[5-{3-fluoropropyl)pyridin-2-yl]-
Figure imgf000197_0002
Di-iert-butyl (4R)-/V-(ferf-butoxycarbonyl)-4-{[5-(3-hydroxypropyl)pyridin-2-yl]methyl}-L- glutamate (68 mg, 0.13 mmol) was dissolved in 2 ml tetrahydrofuran, and cooled to 0 °C. Triethylamine (280 μΙ, 2.01 mmol), 1 , 1 ,2,2,3,3,4,4,4-nonafluorobutane-1 -sulfonyl fluoride (162 mg, 0.53 mmol), and triethylamine trihydrofiuoride (86 mg, 0.53 mmol) were added, and the reaction was stirred at room temperature for 24 h. The same amounts of triethylamine, 1 , 1 ,2,2,3,3,4,4,4-nonafluorobutane-1 -sulfonyl fluoride and triethylamine trihydrofiuoride were added again and the reaction was continued for 1 h. Water (10 ml) was added, and the mixture was extracted with dichloromethane (3 x 10 ml). The organic phases were dried over magnesium sulfate and concentrated. The so derived material was used without further purification.
Yield 72 mg (105.5% crude) ESI+ m/z 51 1 .2 (M+H).
f) (4 ?)-4-{[5-(3-Fluoropropyl)pyridin-2-yl]methyl}-L-glutamic acid
Figure imgf000198_0001
28
Di-ferf-butyl (4f?)-/V-(fert-butoxycarbonyl)-4-{[5-(3-fluoropropyl)pyridin-2-yl]methyl}-L- glutamate (68 mg, 0.13 mmol) was solved in 3 ml trifluoroacetic acid and stirred for 24 h. To the mixture was added toluene (10 ml) and the resulting solution was concentrated in vacuo. The crude product was purified by HPLC. The appropriate fractions were collected, the acetonitrile evaporated under reduced pressure and the remaining aqueous solution was lyophilized.
Yield: 18 mg (45.3%)
1H-NMR (400MHz, DMSO-d6): δ [ppm]= 1 .76 - 1 .87 (m, 1 H), 1 .88 - 2.09 (m, 3H), 2.95 - 3.05 (m, 1 H), 3.05 - 3.14 (m, 4H), 3.82 - 3.92 (m, 1 H), 4.40 (t, 1 H), 4.52 (t, 1 H), 7.34 (d, 1 H), 7.73 - 7.81 (m, 1 H), 8.42 - 8.45 (m, 1 H).
ESI+ m/z 299.3 (M+H).
Example 29
Di-terf-butvl (4ff)-A/-(fer(-butoxvcarbonvn-4- f5-r3-(tosvloxv)propvllpvridin-2-vl>- methvl)-L-qlutamate
Figure imgf000199_0001
Di-ferf-butyl (4R)-W-(iert-butoxycarbonyl)-4-{[5-(3-hydroxypropyl)pyridin-2-yl]methyl}-L- glutamate (25 mg, 0.05 mmoi) was dissolved in dichloromethane (0.5 ml), and p- toluenesulfonic anhydride (Aid rich) (27 mg, 0.08 mmol), triethylamine (13 μΙ, 0.09 mmol) and 4-(dimethylamino)pyridine (0.3 mg, 2 pmol) were added at room temperature. The reaction was stirred for 2h, then poured into 5 ml water. The mixture was extracted with dichloromethane (3 x 5 ml). The organic phases were concentrated in vacuo, and the crude product was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.
Yield: 15 mg (44.8%)
1H-N R (600MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9H), 1 .43 (s, 9H), 1 .44 (s, 9H), 1.90 - 2.02 (m, 4H), 2.47 (s, 3H), 2.63 (t, 2H), 2.88 - 2.98 (m, 2H), 2.99 - 3.08 (m, 1 H), 4.05 (t, 2H), 4.1 1 - 4.18 (m, 1 H), 5.06 (d, 1 H), 7.04 (d, 1 H), 7.30 - 7.34 (m, 1 H), 7.34 - 7.38 (m, 2H), 7.77 - 7.83 (m, 2H), 8.28 (s, 1 H).
ESI+ m/z 663.3 (M+H).
Example 30
Di-ferf-butvl (4/?)-A ferNbutoxvcarbonvl)- -(r5-(2-W4- methvlphenvl)sulfonylloxv}ejjho^
Figure imgf000199_0002
To a solution of 150 mg di-fert-butyl (4R)-A/-(terf-butoxycarbonyl)-4-[(5-hydroxypyridin-2- yl)methyl]-L-glutamate (0.32 mmol) in /V,/V-dimethylformamide (8 ml.) was added 126 mg of cesium carbonate (0.39 mmol), followed by 143 mg of 1 ,2-ethanediol di-p- toluenesulfonate (0.39 mmol). The mixture was stirred for 5 h at room temperature. Water was added, the mixture was extracted with dichloromethane, and the organic layer was washed with brine, dried over magnesium sulfate, and evaporated. The crude product was purified by preparative HPLC (method A) to give 86 mg (40 % yield) of the title compound. H- MR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .37 (s, 9H), 1 .43 (s, 9H), 1 .45 (s, 9H), 1.79 - 2.05 (m, 2H), 2.46 (s, 3H), 2.79 - 3.09 (m, 3H), 4.09 - 4.22 (m, 3H), 4.34 - 4.43 (m, 2H), 5.04 (br. d, 1 H), 6.98 - 7.09 (m, 2H), 7.36 (d, 2H), 7.82 (d, 2H), 8.10 (br. s, 1 H).
ESI+ m/z 665 (M+H)
Example 31
8FlfluoroethoxY)pYridin-2-Yl1methYl}-L-qlutamic acid
Figure imgf000200_0001
[18F]-17
[18F]Fluoride (2120 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eiuted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-tert-butyl (4R)-N-(tert-butoxycarbonyl)-4-{[5-(2-{[(4- methylphenyl)sulfonyl]oxy}ethoxy)pyridin-2-yl]methyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 4 min. The crude product was diluted with water (pH 2) up to 30 mL and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 20 mL ethanol. The cartridge was eiuted with 5 mL phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water) yielding 520 MBq (42% d.c.) (4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}-L-glutamic acid ([18F]-17) in a fraction of 1 ml buffer. Radiochemical purity was determined to be >95% (tR = 2.7 min, analytical HPLC method F). Example 32
'i5-(2-fluoroethoxv)pvridin-2-vllmethvl)hexanedioic acid
Figure imgf000201_0001
32 a) 4-BenzyI 1 ,4-di-ferf-butyl (1 S)-5-[5-(benzyloxy)pyridin
,4-tricarboxylate
Figure imgf000201_0002
To a solution of 360 mg of di-ierf-butyl (5S)-2-(benzyloxycarbonyl)-5-[(fert-butoxy- carbonyl)amino]hexanedioate (0.71 mmol; see example 12f) in /V./V-dimethyl formamide
(10 mL) was added under argon atmosphere 26 mg of sodium hydride (60 % in oil, 0.64 mmol). The resulting mixture was stirred at room temperature for 30 minutes. A solution of 197 mg 5-(benzyloxy)-2-(bromomethyl)pyridine (prepared according to example 17a;
0.71 mmol) in W./V-dimethylformamide (5 mL) was added, and the mixture was stirred at 60 "C for one hour. After cooling to room temperature, the mixture was concentrated in vacuo and the residue was purified by preparative HPLC (method A) to give 327 mg of the title compound (65 % yield).
1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9H, major diastereomer), 1 .36 (s, 9H, minor diastereomer), 1 .40 - 1 .50 (m, 18H), 1 .68 - 2.00 (m, 4H), 3.24 - 3.37 (m, 2H), 4.01 - 4.12 (m, 1 H), 5.03 - 5.23 (m, 4H), 5.97 (br. d, minor diastereomer, 1 H), 6.14 (br. d, major diastereomer, 1 H), 6.82 - 6.92 (m, 1 H), 7.02 - 7.09 (m, 1 H), 7.31 - 7.44 (m, 10H), 8.32 - 8.38 (m, 1 H).
ESI+ m/z 705 (M+H).
b) (5S)-6-fert-Butoxy-2-(fert-butoxycarbonyl)-5-[(fert-butoxycarbonyl)amino]-2-[(5- xanoic acid
Figure imgf000202_0001
To a solution of 310 mg of 4-benzyl 1 .4-di-fert-butyl (1 S)-5-[5-(benzyloxy)pyridin-2-yl]-1 - [(fert-butoxycarbonyl)amino]pentane-1 ,4,4-tricarboxylate (0.44 mmol) in methanol (10 ml.) was added a 10% palladium on carbon hydrogenation catalyst (15 mg) at room temperature. The suspension was stirred for 3 h at room temperature under an atmosphere of hydrogen. The catalyst was removed by filtration and all volatiles were removed in vacuo. The crude product (234 mg, quantitative yield) was used in the next step without further purification.
1H-NMR 1H- M (400MHz. CHLOROFORM-d): δ [ppm]= 1 .27 (s, minor diastereomer, 9H), 1 .28 (s, major diastereomer, 9H), 1 .43 - 1 .52 (m, 18H), 1.68 - 2.23 (m, 4H), 2.91 - 3.06 (m, 1 H), 3.43 - 3.56 (m, 1 H), 4.10 - 4.23 (m, 1 H), 5.15 - 5.27 (m, 1 H), 7.24 - 7.31 (m, 1 H, overlaps with solvent signal), 7.50 - 7.60 (m, 1 H), 8.24 (d, major diastereomer, 1 H), 8.27 (d, minor diastereomer, 1 H).
ESI+ m/z 525 (M+H).
c) Di-fert-butyl (2S)-2-[(ferf-butoxycarbonyl)amino]-5-[(5-hydroxypyridin-2- yl)methyl]hexanedioate
Figure imgf000203_0001
A solution of 220 mg of (5S)-6-fert-butoxy-2-(fert-butoxycarbonyl)-5-[(fert- butoxycarbonyl)amino]-2-[(5-hydroxypyridin-2-yl)methyl]-6-oxohexanoic acid (0.42 mmol) and 100 mg 4-N,/V-dimethylaminopyridine (0.84 mmol) in 1 ,4-dioxan (10 mL) was heated under reflux for 2 hours. The mixture was evaporated and the residue was purified by column preparative HPLC (method C) to give two batches (107 +49 mg; 78 % combined yield) of the target compound. 1H-N R (taken from main batch; 400MHz, CHLOROFORM-d): δ [ppm]= 1 .36 (s, 9H), 1.41 - 1 .50 (m, 18H), 1 .58 - 1 .75 (m, 3H), 1 .78 - 1 .91 (m, 1 H), 2.70 - 2.84 (m, 1 H), 2.90 (dd, 1 H), 3.05 (dd, 1 H). 4.1 1 - 4.23 (m, 1 H), 5.10 - 5.21 (m, 1 H), 5.99 (br. s, 1 H), 7.12 - 7.21 (m, 1 H). 7.28 - 7.35 (m, 1 H), 8.32 - 8.39 (m, 1 H). ESI+ m/z 481 (M+H). d) Di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-{[5-(2-fluoroethoxy)pyridin-2-
Figure imgf000203_0002
To a solution of 54 mg 1 -fluoro-2-iodoethane (0.31 mmol) in /V./V-dimethylformamide (10 mL) was subsequently added 101 mg potassium carbonate (0.73 mmol), followed by 100 mg of di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[(5-hydroxypyridin-2- yl)methyl]hexanedioate (0.21 mmol), and the resulting mixture was stirred for 20 h at room temperature. The mixture was then partitioned between water and ethyl acetate, the aqueous layer was then extracted with ethyl acetate again. The combined organic layers were washed with brine, dried over sodium sulfate, and evaporated. The residue was purified by preparative HPLC, method A to give 56 mg (approx. 90% purity, 46 % purity adjusted yield) of the target compound.
1H-NMR 1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .37 (s, 9H), 1 .45 (s, 18H), 1.55 - 1 .91 (m, 4H), 2.71 - 2.88 (m, 2H), 2.96 - 3.10 (m, 1 H), 4.10 - 4.33 (m, 3H), 4.65 - 4.89 (m, 2H), 5.05 - 5.17 (m, 1 H), 7.03 - 7.20 (m, 2H), 8.23 - 8.29 (m, 1 H). ESI+ m/z 527 (M+H). e) (2S)-2-Amino-5-{[5-{2-fluoroethoxy)pyridin-2-yl]methyl}hexanedioic acid
Figure imgf000204_0001
32
To a solution of 56 mg of di-ferf-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-{[5-(2- fluoroethoxy)pyridin-2-yl]methyl}hexanedioate (0.1 mmol) in anisol (0.7 mL) was added trifluoroacetic acid (1 .5 mL), and the resulting mixture was stirred for 3 h at room temperature. Trifluoroacetic acid was removed under reduced pressure, water (approx. 2 mL) was added and separating anisol (which was expected to encumber preparative HPLC if present in large excess) was removed. The remaining aqueous solution of the crude product was directly loaded onto a preparative HPLC, method B, to give 14 mg of the target compound as white, hygroscopic lyophilisate (approx. 40 % yield).
1H-NMR (300MHz, DEUTERIUM OXIDE): δ [ppm] = 1 .50 - 1 .97 (m, 4H), 2.70 - 2.82 (m, 1 H), 3.10 - 3.20 (m, 2H), 3.68 - 3.81 (m, 1 H), 4.39 - 4.57 (m, 2H), 4.76 - 4.97 (m, 2H, overlaps with solvent signal), 7.71 - 7.80 (m, 1 H), 8.00 - 8.10 (m, 1 H), 8.31 - 8.39 (m,
1 H).
ESI+ m/z 315 (M+H). Example 33
Di-ferf-butyl (2^-2-r(tert-butox ^onyl)aminoV
Figure imgf000205_0001
To a solution of 69 mg 1 ,2-ethanediol di-p-toluenesulfonate (0.19 mmol) in N.N- dimethylformamide (4.5 mL) was subsequently added 61 mg cesium carbonate (0.19 mmol), followed by 45 mg of di-ferf-butyl (2S)-2-[(ferf-butoxycarbonyl)amino]-5-[(5- hydroxypyridin-2-yl)methyl]hexanedioate (0.09 mmol), and the resulting mixture was stirred for 20 h at room temperature. The mixture was then concentrated in vacuo and partitioned between water and dichloromethane. The organic layer was washed with brine, dried over sodium sulfate, and evaporated. Purification by preparative HPLC (Method A) gave 37 mg (58 % purity adjusted yield) of the desired tosylate in approx. 90 % purity.
1H-NMR (300MHz, CHLOROFORM-d): δ [ppm]= 1 .34 - 1 .39 (m, 9H), 1 .41 - 1 .48 (m, 18H), 1 .54 - 1 .90 (m, 4H), 2.46 (s, 3H), 2.70 - 3.07 (m, 3H), 4.10 - 4.21 (m, 3H), 4.34 - 4.42 (m, 2H), 5.05 - 5.15 (m, 1 H), 6.99 - 7.08 (m, 2H), 7.36 (d, 2H), 7.83 (d, 2H), 8.08 - 8.13 (m, 1 H).
ESI+ m/z 679 (M+H).
Example 34
(2S)-2-Amino-5-ir5- 2-r18Flfluoroethoxv)pvridin-2-vllmethvl)hexanedioic acid
Figure imgf000206_0001
[ 8F]-32
[18F]Fluoride (2482 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eiuted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-ferf-butyl (2S)-2-[(ierf-butoxycarbonyl)amino]-5-{[5-(2- {[(4-methylphenyl)sulfonyl]oxy}ethoxy)pyridin-2-yl]methyl}hexanedioate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 "C for 10 min. After cooling to rt, 2M HCl (1 mL) was added and the mixture was stirred at 120 "C for 5 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. The cartridge was eiuted with 5 mL phosphate buffer (7 g Na2HPO.r2H20; 6 g NaCI in 1 L water) yielding 307 MBq (19% d.c.) (2S)-2-Amino-5-{[5-(2-[18F]fluoroethoxy)pyridin-2-yl]methyl}hexanedioic acid ([18F]-32) in a fraction of 1 ml buffer. Radiochemical purity was determined to be >99% (tR = 2.8 min, analytical HPLC method F).
Example 35
(4/?)-4 r5-{2-fluoroethoxv)-1-oxidopvridin-2-vllmethvl)-L-qlutamic acid
Figure imgf000206_0002
a) di-ferf-ButyS (4 ?)-N-{fert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)-1 -oxidopyridin- 2-yl]methyl}-L-glutamate
Figure imgf000207_0001
To a solution of 350 mg di-fert-butyl (4R)-/V-(fert-butoxycarbonyl)-4-{[5-(2- fluoroethoxy)pyridin-2-yl]methyl}-L-glutamate (0.68 mmol; see Example 17d) in dichloromethane (5 mL) was added 185 mg mefa-chloro peroxybenzoic acid (70%), and the mixture was stirred for 1 h at room temperature. The mixture was extracted with aqueous sodium bicarbonate, followed by re-extraction of the aqueous layer with dichloromethane. The combined organic layers were concentrated in vacuo, and the residue was purified by preparative HPLC (Method D) to give 340 mg of the target compound (93 % yield).
1H-N R (300MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H), 1 .43 (s, 9 H), 1 .47 (s, 9 H), 1 .86 - 2.14 (m, 2 H), 2.88 - 3.23 (m, 3 H), 4.10 - 4.31 (m, 3 H), 4.62 - 4.89 (d, 2 H), 5.12 (d br, 1 H), 6.84 (dd, 1 H), 7.13 (d, 1 H), 8.04 (d, 1 H). ESI+ m/z 529 (M+H).
Figure imgf000207_0002
To a solution of 170 mg of di-fert-butyl (4R)-N-(tert-butoxycarbonyl)-4-{[5-(2- fluoroethoxy)-1 -oxidopyridin-2-yl]methyl}-L-glutamate (0.32 mmol) in dichloromethane (10 mL) was added trifluoroacetic acid (124 pL, 5 eq) and the mixture was stirred for 2 h at room temperature. LC/MS revealed substantial quantities of starting material were present; hence an additional 5 eq of trifluoroacetic acid were added and stirring at room temperature was continued overnight. Repeated LC/MS still showed incomplete removal of the protecting groups. The mixture was evaporated, re-dissolved in trifluoroacetic acid and dichloromethane (2 mL each) and stirred at room temperature for another 2 h, whereupon the reaction was complete. The mixture was evaporated and the residue was purified by preparative HPLC (Method E), followed by lyophilisation to give 95 mg of the target compound as light brown lyophilisate in approx. 90 % purity (84 % purity adjusted yield).
1H-NMR (300MHz, DMSO-d6): δ [ppm]= 1 .60 - 1 .94 (m, 2 H), 2.73 - 2.87 (m, 1 H), 2.92 - 3.06 (m, 1 H), 3.08 - 3.25 (m, 1 H), 3.51 - 3.65 (m, 1 H), 4.18 - 4.45 (m, 2 H), 4.56 - 4.90 (m, 2 H), 7.05 (dd, 1 H), 7.30 (d, 1 H). 8.1 1 (d, 1 H).
ESI+ m/z 317 (M+H).
Example 36
Di-ferf-butyl (4/?)-A/-(feri-butoxYcarbonYl)^-{r5-(2-{r(4- methvlphenvl)sulfonvlloxv)ethoxy)-1 -oxidopvridin-2-vllmethyl)-L-qlutamate
Figure imgf000208_0001
To a solution of 125 mg di-ferf-butyl (4R)-N-(ferf-butoxycarbonyl)-4-{[5-(2-{[(4- methylphenyl)sulfonyl]oxy}ethoxy)pyridin-2-yl]methyl}-L-glutamate (0.19 mmol; see Example XB) in dichloromethane (10 mL) was added 51 mg meia-chloro peroxybenzoic acid (70%), and the mixture was stirred for 3 h at room temperature. The mixture was extracted with aqueous sodium bicarbonate, followed by re-extraction of the aqueous layer with dichloromethane. The combined organic layers were dried over magnesium sulfate and concentrated in vacuo, and the residue was purified by preparative HPLC. (Method D) to give 104 mg of the target compound as colourless foam (81 % yield). Ή-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .35 (s, 9 H), 1 .43 (s, 9 H), 1.47 (s, 9 H), 1 .84 - 2.13 (m, 2 H), 2.48 (s, 3 H), 2.89 - 3.18 (m, 3 H), 4.08 - 4.26 (m, 3 H), 4.32 - 4.41 (m, 2 H), 5.1 1 (d br, 1 H), 6.68 - 6.76 (m, 1 H), 7.09 (d, 1 H), 7.38 (d, 2 H), 7.78 - 7.89 (m, 3 H). ESI+ m/z 681 (M+H). Example 37
Figure imgf000209_0001
[ 8F]-35
[18F]Fluoride (2500 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-tert-butyl (4R)-N-(tert-butoxycarbonyl)-4-{[5-(2-{[(4- methylphenyl)sulfonyl]oxy}ethoxy)-1 -oxidopyridin-2-yl]methyl}-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 5 min. The crude product was diluted to 30 mL with water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 50 mL ethanol. The cartridge was eluted with 5 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water) yielding 765 MBq (45% d.c.) 4-{[5-(2-[ 8F]fluoroethoxy)-1 -oxidopyridin-2-yl]methyl}-L-glutamic acid ([18F]- 35) in a fraction of 2 mi buffer. Radiochemical purity was determined to be >93% (tR = 2.8 min, analytical HPLC method F). Further purification via an additional OASIS MCX cartridge (OASIS MCX plus, Waters) affored a fraction of 24 MBq [18F]-35 in 1 mL buffer with a radiochemical purity of >97%.
Example 38
(2S)-2-amino-5-{'2-f4-(2-fluoroethoxv)phenvllethvl)hexanedioic acid
Figure imgf000209_0002
38 a) 1 -{Benzyloxy)-4-(2-bromoethyl)benzene
Figure imgf000210_0001
To a cooled (0°C) solution of 3.00 g 4-benzyloxy phenethyl alcohol (13.1 mmol) in dichloromethane (132 mL) were added subsequently 5.17 g of triphenylphosphine (19.7 mmol) and 6.54 g carbon tetrabromide (19.7 mmol). The resuling mixture was stirred for 2 h at room temperature and was then evaporated. The residue was triturated with diethyl ether at -20°C for 30 minutes, and then all solides were removed by filtration, and the filtrate was concentrated in vacuo. The residue was subjected to column chromatography on silica gel (1 % > 10 % ethyl acetate in hexane) to give 2.80 g of the target compound (73 % yield) as a pale yellow oil crystallising upon standing. H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= 3.1 1 (t, 2 H), 3.54 (t, 2 H), 5.06 (s, 2 H), 6.91 - 6.98 (m, 2 H), 7.10 - 7.18 (m, 2 H), 7.30 - 7.48 (m, 5 H). b) 4-Benzyl 1 ,4-di-fert-butyl (1 S)-6-[4-<benzyloxy)phenyl]-1 -[(tert- ,4-tricarboxylate
Figure imgf000210_0002
To a solution of 1 .1 1 g di-fert-butyl (5S)-2-(benzyloxycarbonyl)-5-[(fert-butoxycarbonyl)- aminojhexanedioate (2.19 mmol; see example 12f) in A/./V-dimethyl formamide (30 mL) was added under argon atmosphere 96 mg of sodium hydride (60 % in oil, 2.40 mmol), and the mixture was stirred for 30 min at room temperature. Subsequently, a solution of 700 mg of 1 -(benzyloxy)-4-(2-bromoethyl)benzene (2.40 mmol) in /V,/V-dimethyl formamide (15 mL) was added, an the mixture was stirred at 60 °C for 3 hours. The nixture was concentrated in vacuo, partitioned between water and ethyl acetate, and the organic layer was washed with brine, dried over sodium sulfate, and evaporated. The residue was purified by preparative HPLC (Method A) to give 413 mg of the target compound in approx. 90 % purity (26 % purity adjusted yield). H-NMR (300 MHz, CHLOROFORM-d): δ [ppm]= 1 .33 - 1 .39 (m, 9 H), 1 .41 - 1 .51 (m, 18 H), 1 .57 - 2.14 (m, 6 H), 2.29 - 2.48 (m, 2 H), 4.15 - 4.26 (m, 1 H), 5.00 - 5.25 (m, 5 H), 6.84 - 6.91 (m, 2 H), 6.98 - 7.06 (m, 2 H), 7.28 - 7.47 (m, 10 H).
ESI+ m/z 718 (Μ+Η)·
ESI- m/z 762 (M+HCOO ). c) (5S)-6-ferf-Butoxy-2-(ferf-butoxycarbonyl)-5-[(fert-butoxycarbonyl)amino]-2-[2- anoic acid
Figure imgf000211_0001
To a solution of 125 mg of 4-benzyl 1 ,4-di-fert-butyl (1 S)-6-[4-(benzyloxy)phenyl]-1 - [(fert-butoxycarbonyl)amino]hexane-1 ,4,4-tricarboxylate (0.18 mmol) in methanol (5 ml.) was added 10% palladium on charcoal (15 mg) and the mixture was stirred under an atmosphere of hydrogen for 16 h at room temperature. The catalyst was removed by filtration, and the filtrate was evaporated to give the target compound (84 mg, 89 % yield) which was used without further purification.
1H-N R (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .44 (s, 9 H), 1 .47 (s, 9 H), 1 .54 (s, 9 H), 1 .59 - 2.44 (m, 7 H), 2.46 - 2.57 (m, 1 H), 4.09 - 4.25 (m, 1 H), 5.08 - 5.20 (m, 1 H), 6.75 (m, 2 H), 6.95 - 7.03 (m, 2 H).
ESI+ m/z 538 (M+H). d) Di-ferf-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[2-{4- hydroxyphenyl)ethyl]hexanedioate
Figure imgf000212_0001
To a solution of 370 mg (5S)-6-terf-butoxy-2-(tert-butoxycarbonyl)-5-[(terf- butoxycarbonyl)amino]-2-[2-(4-hydroxyphenyl)ethyl]-6-oxohexanoic acid (0.69 mmol) in 1 .4-dioxane (30 ml.) was added 210 mg of 4-/V,/V-dimethylaminopyridine (1 .72 mmol) and the mixture was stirred overnight at 100°C (bath temperature), followed by refluxing for another 18 h. After cooling to room temperature, the mixture was concentrated in vacuo. The residue was purified by preparative HPLC (Method A) to give 169 mg (50 % yield) of the target compound. In addition, 38 mg of unreacted starting material were recovered.
1H-N R (400MHz, CHLOROFORM-d): δ [ppm]= 1 .42 - 1 .51 (m, 27 H), 1 .53 - 1 .82 (m, 5 H), 1 .82 - 1 .94 (m, 1 H), 2.19 - 2.35 (m, 1 H), 2.43 - 2.61 (m, 2 H), 4.10 - 4.24 (m, 1 H), 4.85 (s br, 1 H), 5.04 (d br, 1 H), 6.76 (d, 2 H), 7.03 (d, 2 H). ESI+ m/z 494 (M+H). e) (2S)-2-fert.-Butoxycarbonylamino-5-{2-[4-(2-fluoro-ethoxy)-phenyl]-ethyl}- ester
Figure imgf000212_0002
53 mg (0.30 mmol) 1 -Fluoro-2-iodoethane were dissolved in 5ml dimethylformamide 98 mg (0.71 mmol) potassium carbonate and 100 mg (0.20 mmol) (2S,5RS)-2-tert - Butoxycarbonylamino-5-[2-(4-hydroxy-phenyl)-ethyl]-hexanedioic acid di-fert.-butyl ester added. The mixture was stirred at room temperature over night. For workup, water and ethyi acetate were added, the phases separated and the water extracted with ethyl acetate twice. Combined organic phases were dried (Na2S04), filtered and evaporated. The raw product was absorbed on I solute and chromatographed on a Biotage I solera system (SNAP NH 1 10g, A = n-hexane, B = ethyl acetate, A 2CV, A to 47%B in 9.4CV, 5CV 50%B, 50mL/min, Fr. a 22mL). Fractions 29 to 32 were collected to give 65 mg (59%) of (2S, 5RS)-2-fert.-Butoxycarbonylamino-5-{2-[4-(2-fluoro-ethoxy)-phenyl]-ethyl}- hexanedioic acid di-iert.-butyl ester as clear oil.
MS (ESI+): m/e = 562 (M - Na+), 540 (M - H* ), 440 (M + H+ - C4H8 - C02), 328 (M + H+ -
3 C4H8 - C02), 310 (328 - H2O). 9F NMR (376 MHz, CHLOROFORM-d): δ ppm -223.9 (tt, J=47.0, 27.5 Hz).
Ή NMR (CHLOROFORM-d ,400MHz): δ (ppm) 7.09 (d, J=8.6 Hz, 2H, Ar-H), 6.85 (d, J=8.6 Hz, 2H, Ar-H), 5.03 (d, J=7.3 Hz, 1 H, NH), 4.74 (dt, 2JHF=47.5HZ, J=3.8 Hz, 2H, CH2F), 4.10 - 4.27 (m, 1 H), 4.20 (dt, 3JHF=27.8HZ, J=4.3 HZ, 2H, CH20), 2.45 - 2.64 (m, 1 H), 2.18 - 2.36 (m, 1 H), 1 .83 - 1 .96 (m, 1 H), 1 .71 - 1 .82 (m, 1 H), 1 .64 (s, 5H), 1 .41 - 1.52 (m, 27H, tBu). 3C NMR (CHLOROFORM-d , 101 MHz): δ (ppm) 175.0, 174.8 (C-6), 171 .7, 171 .7 (C-1 ), 156.7, 156.7 (Ar C-4), 155.4, 155.3 (2 C-1 ), 134.6, 134.5 (Ar C-1 ), 129.4 (Ar C-2/6), 1 14.7 (Ar C-3/5), 82. .0 Hz, CH2F), 81 .9, 81 .9 (6 C-1 ), 80.4, 80.4 (1 C-1 ), 79.6 (2C-2), 67.2 (d,
Figure imgf000213_0001
CH20), 54.0, 53.6 (C-2), 45.8, 45.4 (C-5), 34.7, 34.5 (5-CH2), 32.7 (Ar CH2), 30.7, 30.5 (C-3), 28.4 (2 C-3), 28.2, 28.2 (6 C-2), 28.0 (1 C-2), 27.9 (C-4).
The sample is a mixture of the diastereomers. f) (2S)-2-amino-5-{2-r4-(2-fluoroethoxY)phenYl1ethYl}hexanedioic acid
Figure imgf000214_0001
20 mg (37 mol) of (2S)-2-iert.-Butoxycarbonylamino-5-{2-[4-(2-fluoro-ethoxy)-phenyl]- ethyl}-hexanedioic acid di-ferf.-butyl ester were dissolved in 2 ml_ dichloromethane (dried over 4A molecular sieve) and 1 ml_ trifluoroacetic acid were added. The reaction was stirred at room temperature for 30 min, after which the solution was directly applied to reversed phase chromatography on a Biotage system (Flash 12+M cartridge, A = water, B = acetonitrile, A 1 CV. A to 50%B in 10CV, 2CV 50%B, 12mL/min). Fraction 6 was lyophiiized to give 2 mg (1 1 %) of (2R,5RS)-2-Amino-5-{2-[4-(2-fiuoro-ethoxy)- phenyl]-ethyl}-hexanedioic acid as the Tfa-salt.
19F NMR (376 MHz, DMSO-d6): δ ppm -73.5 (s. br., 3F, Tfa), -222.0 (tt, J=47.0, 29.8 Hz, 1 F).
Example 39
IgSl^e -Butoxycarbonylamino-S^
Figure imgf000214_0002
90 mg (0.18 mmol) (2S)-2-fert.-Butoxycarbonylamino-5-[2-(4-hydroxy-phenyl)-ethyl]- hexanedioic acid di-fert.-butyl ester were dissolved in 10ml dimethylformamide, 208 mg (0.64 mmol) cesium carbonate and 473 mg (1 .28 mmol) ethylene glycol di-(p- toluolsulfonate) added and the mixture stirred at room temperature for 1 h. The solvent was evaporated, the mixture taken up in ethyl acetate and absorbed on I solute. Chromatography on a Biotage I solera system (SNAP 10g. A = n-hexane, B = ethyl acetate, A 2CV, A to 47%B in 10CV, 3CV 50%B, 12mL/min, Fr. a 22mL) gave 82 mg material, which still contained ethylene ditosylate. The compound was further purified by preparative HPLC. (Agilent: Prep 1200, 2 x Prep Pump, DLA, MWD, ELSD, Prep FC XBrigde C185μιη 100x30 mm; A = H20; B = Acetonitrile; 0-17.5 min 65-100% B, 17,5- 20 min 100% B; 38 mL/min; RT; 82 mg / 2.4 mL DMSO/MeCN 1:2; 2 x 1,2 mL; MWD 210 nm). The fractions eluting at 10,0 - 11.5 min were collected to give 73 mg (58%) (2S, 5RS)-2-iert.-Butoxycarbonylamino-5-(2-{4-[2-(toluene-4-sulfonyloxy)-ethoxy]- phenyl}-ethyl)-hexanedioic acid di-fert.-butyl ester in >99 % purity. NMR (CHLOROFORM-d ,400MHz): δ (ppm) 7.81 (d, J=8.1 Hz, 2H, Ts-H), 7.33 (d, J=8.1 Hz, 2H, Ts-H), 7.03 (d, J=8.6 Hz, 2H, Ar-H), 6.70 (d, J=8.2 Hz, 2H, Ar-H), 5.03 (d, br.„ J=7.8 Hz, 1H, NH), 4.35 (t, J=4.5 Hz, 2H, OCH2), 4.18 (s, 1H, 2-H), 4.11 (t, J=4.8 Hz, 2H, OCH2), 2.46 - 2.62 (m, 2H, ArCH2), 2.44 (s, 3H, TsCH3), 2.17 - 2.33 (m, 1H), 1.80- 1.93 (m, 1H), 1.71 - 1.80 (m, 1H), 1.52- 1.66 (m, 3H), 1.38- 1.51 (m, 28H).
13C NMR (CHLOROFORM-d ,101MHz): δ (ppm) 175.0, 174.8 (C-6), 171.7, 171.7 (C-1), 156.3, 156.3 (Ar C-4), 155.4, 155.3 (2 C-1), 144.9 (Ts C-4), 134.7, 134.7 (Ar C-1), 133.0 (Ts C-2), 129.9 (Ts C-3/5), 129.4 (Ar C-2/6), 128.1 (Ts C-2/6), 114.6, 114.6 (Ar C-3/5), 81.9, 81.9 (1 C-1), 80.5, 80.4 (6 C-1), 79.6 (br., 2 C-2), 68.2 (OCH2), 65.6 (OCH2), 54.0, 53.6 (C-2), 45.8, 45.4 (C-5), 34.6, 34.5 (5 CH2), 32.7 (ArCH2), 30.7, 30.5 (C-3), 28.4 (1 C-2), 28.2, 28.2 (6 C-1), 28.0 (br., 2 C-3), 27.9 (C-4), 21.7 (Ts-CH3).
The compound is a mixture of diastereomers.
Example 40
ethoxv)phenvllethyl)hexanedioic acid
Figure imgf000215_0001
[18F]-38 [18F]Fluoride (750 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of (2S)-2-fert.-Butoxycarbonylamino-5-(2-{4-[2-(toluene-4- sulfonyloxy)-ethoxy]-phenyl}-ethyl)-hexanedioic acid di-ferf.-butyl ester in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt, 2M HCI (1 mL) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted to 30 mL with water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2). The cartridge was eluted with 15 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water) yielding 134 MBq (31 % d.c.) (2S)-2-amino-5-{2-[4-(2-fluoroethoxy)phenyl]ethyl}hexanedioic acid ([18F]-38). Radiochemical purity was determined to be >96% (tR = 3.2 min, analytical HPLC method E; tR = 21 .8, 23.3 min*, analytical HPLC method G). The two isomers (2S.5S)- 2-amino-5-{2-[4-(2-fluoroethoxy)phenyl]ethyl}hexanedioic acid ([18F]-38a) and (2S.5R)- 2-amino-5-{2-[4-(2-fluoroethoxy)phenyl]ethyl}hexanedioic acid ([18F]-38b) can be separated by analytical HPLC method G (OPA-derivatization").
Example 41
Figure imgf000216_0001
a) (2S)-5-Benzyloxycarbonyl-6-(4-benzyloxy-phenyl)-5-fert.-butoxycarbonyl-2-fert.- butoxycarbonylamino-hexanoic acid fert.-butyl ester.
Figure imgf000217_0001
1.00 g (1 .97 mmol) (2S)-2-Benzyloxycarbonyl-5-terf.-butoxycarbonylamino-hexane dioic acid di-ferf.-buty ester were dissolved in 25 mL dimethylformamide, 87 mg (2.2 mmol) NaH (60% in mineral oil) added and stirred at room temperature for 30 min. 601 mg (2.17 mmol) 4-benzloxy benzyl bromide 1 mL dimethylformamide were added and the reaction stirred for 1 h at 60°C. The solvent was removed i. vac. And the residue partitioned between ethyl acetate and brine. The organic phase was adsorbed on I solute and directly chromatographed on a Biotage I solera system (SNAP 100g, A = n- Hexane, B = ethyl acetate, A 3CV, A to 25%B in 10CV, 4.7CV 25%B, 50mL/min, Fr. a 18mL). Fractions 68 to 75 were collected to give 1 .09 g (79%) of (2S,5Sf?)-5- Benzyloxycarbonyl-6-(4-benzyloxy-phenyl)-5-fert.-butoxycarbonyl-2-fert.- butoxycarbonylamino-hexanoic acid iert.-butyl ester.
MS (ESI' ): m/e = 726 (M + Na+), 704 (M - H+), 648 (M + H+ - C4H8), 592 (M + H+ - 2 C4H8), 536 (M + H+ - 3 C.Ma), 492 (M + H+ - 3 C4H8 - C02).
Ή MR (CHLOROFORM-d ,400MHz): δ (ppm) 7.30 - 7.45 (m, 10H, Bn-H), 6.92 - 7.00 (m, 2H, Ar 2-H), 6.78 - 6.85 (m, 2H, Ar 3-H), 5.07 - 5.20 (m, 2H, 5-OCH2), 4.96 - 5.06 (m, 3H, 6-OCH2, NH), 4.14 - 4.21 (m, 1 H), 3.19 (d, br., J=14.4 Hz, 1 H, 6-H), 3.07 (d, br., J=13.9 Hz, 1 H, 6-H), 1 .61 - 1 .91 (m, 4H, 3-H, 4-H), 1 .38 - 1 .48 (m, 18H, tBu), 1 .31 - 1.37 (m, 9H, tBu). 3C NMR (CHLOROFORM-d , 101 MHz): δ (ppm) 171 .3, 171 .3 (5 C1 Bn), 171 .1 , 171 .0 (5 C-1 tBu), 169.8, 169.7 (C-1 ), 157.8 (Ph C-4), 155.2 (br., 2 C-1 ), 137.1 (6 Bn C-2), 135.4 (5 C-2), 131 .0, 131 .0 (Ph C-2/6), 128.7 (br., 5 Bn C-3/7), 128.6 (6 Bn C-3/7), 128.6 (6 Bn C-4/6), 128.4, 128.4 (5 Bn C-4/6), 128.3 (br., Ph C-1 ), 128.0 (5 Bn C-5), 127.5 (6 Bn C-5), 1 14.7, 1 14.7 (Ph C-3/5), 82.1 (1 C-2), 82.0 (5 C-2 tBu), 79.6 (2 C-2), 70.0 (6 Bn C-1 ), 66.9 (br., 5 Bn C-1 ), 59.0, 59.0 (C-5), 53.8 (C-2), 37.6, 37.1 (C-6), 28.4 (2 C-3), 28.0, 28.0 (6 C-3 tBu), 27.8, 27.8 (1 C-2), 27.7 (C-4), 27.5, 27.4 (C-3). The material is a mixture of diastereomers.
The preparation was repeated with 6.00 g (1 1 .8 mmol) 2S,5RS)-2-Benzyloxycarbonyl-5- fert.-butoxycarbonylamino-hexanedioic acid di-ferf.-butyl ester and 3.60 g 4-benzyloxy benzyl bromide to give 6 g raw product which was used in the next steps without further purification. b) (2S)-2-ferf.-Butoxycarbonylamino-5- 4-hydroxy-benzyl)- exanedioic acid di-
Figure imgf000218_0001
Hydrogenation:
The raw material obtained above 6.00 g (8.52 mmol) was dissolved in 50 ml_ methanol and 900 mg Pd/C 10% added under Argon atmosphere. The argon was replaced by hydrogen and the mixture hydrogenated for 3 h at room temperature (h½ being supplied by a balloon under normal pressure), after which UPLC- S indicated the reaction to be complete. The catalyst was filtered off over a PTFE-filter and the resulting clear solution evaporated i. vac..8.8 g (>100%) raw product were obtained.
Decarboxylation:
The material was dissolved in 400 ml_ Dioxan, 5, 13 g (42.0 mmol) 4-dimethylamino- pyridine added and stirred over night at 100°C. The resulting yellowish suspension was evaporated i. vac, the material dissolved in ethyl acetate and absorbed on I solute. Test: chromatography of a small amount (Biotage I solera system; SNAP 25g, A = n- Hexane, B = ethyl acetate, A 2CV, A to 50%B in 10CV, 3CV 25%B, 25mL/min. Fr. a 12mL) gave 980 mg.
Main Chromatography . (Biotage I solera system; SNAP 100g, A = n-Hexane, B = ethyl acetate, A 2CV, A to 50%B in 10CV, 3CV 25%B, 50mL/min, Fr. a 12mL) gave 3.46 g. Combined yield: 4.44 g (79%) of (2S,5f?S)-2-fert.-Butoxycarbonylamino-5-(4-hydroxy- benzyl)-hexanedioic acid di-ferf. -butyl ester. Ή N R (CHLOROFOR -d ,400MHz): δ (ppm) 6.97 - 7.06 (m, 2H, Ph 2/6-H), 6.72 (d, J=8.3 Hz, 2H, Ph 3/5-H), 5.43 (br. s., 1H, NH), 5.00 - 5.11 (m, 1H, 2-H), 4.12 - 4.23 (m, 1H, 5-H), 2.75 - 2.86 (m, 1H, PhCH2), 2.57 - 2.67 (m, 1H, PhCH2), 2.43 - 2.57 (m, 1H, 3- H), 1.72 - 1.87 (m, 1H, 3-H), 1.53 - 1.65 (m, 2H, 4-H2), 1.45 (s, 18H, OtBu), 1.33 - 1.39 (m, 9H, Boc).
13C NMR (CHLOROFORM-d ,101MHz): δ (ppm) 174.7, 174.6 (C-6), 171.8, 171.6 (C-1), 155.5, 155.4 (2 C-1), 154.4 (Ph C-4), 131.1 (Ph C-1), 130.1 (Ph C-2/6), 115.2, 115.2 (Ph C-3/5), 82.0, 82.0 (1 C-1), 80.6, 80.5 (6 C-1), 79.8 (2 C-2), 53.9, 53.6 (C-2), 48.4, 47.9 (C-5), 37.9, 37.7 (PhCH2), 30.7, 30.5 (C-4), 28.4 (2 C-3), 28.1 (6 C-2), 28.0 (1 C-
2), 27.7, 27.7 (C-3).
The material is a mixture of diastereomers. benzyl)hexanedioic acid
Figure imgf000219_0001
(2S)-2-tert.-Butoxycarbonylamino-5-(4-hydroxy-benzyl)-hexanedioic acid di-fert.-butyl ester (159 mg, 332 pmol) was solved in formic acid (20 ml) and the solution was stirred at 63 °C for one hour. The solvent was removed under reduced pressure and the residue was taken up in methanol and concentrated and dried in vacuo. The product was taken up in water and lyophilized to yield 78 mg (79%) of the title compound (contains -0.4 eq formic acid and traces of methanol).
Ή-NMR (300MHz, DEUTERIUM OXIDE): δ [ppm]= 1.52- 1.91 (m, 4H), 2.59 - 2.72 (m, 1H), 2.73 - 2.84 (m, 2H), 3.63 - 3.80 (m, 1H), 6.54 - 6.92 (m, 2H), 6.95 - 7.22 (m, 2H).
MS (ESI*): m/e = 268.1 (M + H'), 250.1 (M + H' - H20). The material is a mixture of diastereomers. d) dimethyl (2S)-2-amino-5-(4-hydroxybenzyi)hexanedioate hydrochloride
Figure imgf000220_0001
(2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid (Example 42) (994 mg, 2.98 mmol) was solved in methanol (20 ml) and at 0 °C thionyl dichloride (1 .17 ml, 15.97 mmol) were added slowly. After complete addition, the cooling bath was removed and the reaction was stirred for three days at room temperature. The solvent was removed and the residue was dried in vacuo to yield 828 mg (86%) of white foam. The crude product was used in the following step without further purification.
MS (ESI*): m/e = 296.2 (M + hT ), 264.1 (M + H* - CH3OH).
The material is a mixture of diastereomers. methoxy)benzyl]hexanedioate
Figure imgf000220_0002
Dimethyl (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioate hydrochloride (200 mg, 0.54 mmol) were solved in DMF (5 ml) and at 0 °C sodium hydride (34 mg, 1 .14 mmol) were added. After 30 min, bromofluoromethane (1 ,35 mmol) were added and the resulting mixture was stirred at 0 °C for one hour. The mixture was then poured into water and extracted three times with methylene chloride. The organic phase was dried with sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography to yield 37 mg (20.8%) of the product.
MS (ESP ): m/e = 328.1 (M + hT ). The material is a mixture of diastereomers. e) (2S)-2-amino-5-[4-{fluoromethoxy)benzyl]hexanedioic acid
Figure imgf000221_0001
Dimethyl (2S)-2-amino-5-[4-(fluoromethoxy)benzyl]hexanedioate (37 mg, 1 13 μιτιοΙ) was solved in 2 ml of amixture of tetrahydrofurane and water (2: 1 ), and to the solution, four drops of 1 N sodium hydroxide were added. The mixture was stirred at room temperature for 14h and then concentrated in vacuo. The residue was purified by preparative HPLC and the according fractions were lyophiiized to yield 2 mg (4.3%) of the title compound.
Ή NMR (400 MHz, DMSO-d6) δ ppm 7.14 (d, J=8.8 Hz, 2 H), 6.96 (d, J=8.6 Hz, 2 H), 5.78 (d, J=54.8 Hz, 2 H), 3.10 - 3.16 (m, 2 H, overlaps with water signal), 2.73 (dd, J=13.6, 9.1 Hz, 1 H), 2.61 (dd, J=13.6, 5.6 Hz, 1 H), 1 .51 - 1 .79 (m, 4 H).
MS (ESI*): m/e = 300.0 (M + H+). The material is a mixture of diastereomers.
Example 42
(2S)-2-amino-5-(4-hvdroxvbenzvHhexanedioic acid benzyl)hexanedioic acid - mixture of isomers at C5
Figure imgf000221_0002
See example Example 41 c
b) (2S)-2-amino-5-{4-hydroxybenzyl)hexanedioic acid - Separation of isomers C5- 1 and C5-2
Figure imgf000222_0001
Isomer C5-1 Isomer C5-2
1.56 g (3.25 mmol ) (2S)-2-iert.-Butoxycarbonylamino-5-(4-hydroxy-benzyl)-hexanedioic acid di-tert. -butyl ester (Example 41 b) were purified by chiral HPLC (Chiralpak AD-H 5 pm 250x300 mm; hexan/2-propanol; 40 mLJmin). Two isomers were isolated (isomer 1 : 362 mg and isomer 2: 424 mg). 0.15 g (0.31 mmol) isomer 1 and 0.15 g (0.31 mmol) isomer 2 were individually deprotected according to the procedure described in Example 41 c, yielding 42 mg (51 %) (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid - Isomers C5-1 and 40 mg (48%) (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid - Isomers C5-2.
Example 43
(2S)-2-amino-5-f4-(fluoromethoxv)benzyllhexanedioic acid a) (2S)-2-amino-5-[4-{fluoromethoxy)benzyl]hexanedioic acid - Mixture of isomers ert&Ziegler modular lab)
Figure imgf000222_0002
[18F]-41
[18F]Fluoride (43500 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vessel 1 . The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 100 pL dibromo methane in 0.9 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 130 °C for 5 min. The reaction vessel 1 was colled to 50 °C and bromo [18F]fluoromethane was distilled through 4 silica cartridges (Silica plus, Waters) into reaction vessel 2 containing 700 pL DMSO. A solution of 2.1 mg (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid, 100 pL water, 10 pL 10% NaOH solution in 400 pL DMSO was added after distillation was complete. The resulting mixture was heated at 1 10 °C for 5 min. After cooling to 50 °C, the crude product was diluted with 50 mL water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, waters). The cartridge was washed with 20 mL water (pH 2) and the activity was etuted with 5 mL ethanol through a Strata-X-C cartridge (200 mg, Phenomenex). Activity was eluted from the SCX cartridge with 5 mL phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water) yielding 4100 MBq (15% d.c.) (2S)-2-amino- 5-[4-(fluoromethoxy)benzyl]hexanedioic acid ([18F]-41 ). Radiochemical purity was determined to be >99% (tR = 3.0 min, analytical HPLC method C; R = 6.2 min, analytical HPLC method H, tR = 19.6, 20.7 min*, analytical HPLC method G). *The two isomers (2S)-2-amino-5-[4-(fluoromethoxy)benzyl]hexanedioic acid ([18F]-41 C5-1 ) and ([18F]-41 C5-2) can be separated by analytical HPLC method G ("OPA-derivatization"). xy)benzyl]hexanedioic acid - Isomer C5-1
Figure imgf000223_0001
Isomer C5-1
[18F]Fluoride (10000 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vessel 1 . The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 100 μί dibromo methane in 0.9 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 130 °C for 5 min. The reaction vessel 1 was colled to 50 °C and bromo [18F]fluoromethane was distilled through 4 silica cartridges (Silica plus, Waters) into reaction vessel 2 containing 700 μί DMSO. A solution of 2.1 mg (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid (isomer 1 ), 100 μί water, 10 μί 10% NaOH solution in 400 μί DMSO was added after distillation was complete. The resulting mixture was heated at 1 10 °C for 5 min. The crude product was diluted up to 30 mL with water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, waters). The cartridge was washed with 20 mL water (pH 2) and the activity was etuted with ethanol in 1 mL fractions. Fraction 1 (containing 799 MBq) was diluted with 30 mL water and passed through a Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL ethanol and the activity was eluted from the SCX cartridge with 5 mL phosphate buffer (7 g Na2HPO.r2H20; 6 g NaCI in 1 L water) in fractions of 1 mL, yielding 642 MBq (15% d.c.) (2S)-2-amino-5-[4- (fluoromethoxy)benzyljhexanedioic acid ([18F]-41 isomer C5-1 ) in 1 mL buffer (fraction 3). Radiochemical purity was determined to be >99% (tR = 3.0 min, analytical HPLC method C; tR = 6.4 min, analytical HPLC method H, tR = 19.5, analytical HPLC method G). xy)benzyl]hexanedioic acid - isomer C5-2
Figure imgf000224_0001
[18F]Fluoride (16500 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accell Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vessel 1 . The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 100 μί dibromo methane in 0.9 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 130 °C for 5 min. The reaction vessel 1 was colled to 50 °C and bromo [18F]fluoromethane was distilled through 4 silica cartridges (Silica plus, Waters) into reaction vessel 2 containing 1000 μί DMF.
To 500 μί of the solution of bromo [18F]fluoromethane in DMF were addded 2.1 mg (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid (isomer 2), 100 μί water, 10 L 10% NaOH and 500 μί DMF. The resulting mixture was heated at 1 10 °C for 5 min. The crude product was diluted up to 30 mL with water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, waters). The cartridge was washed with 10 mL water (pH 2) and the activity was etuted with ethanol in 1 mL fractions. Fraction 1 (containing 308 MBq) was diluted with 30 mL water and passed through a Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 10 mL ethanol and the activity was eluted from the SCX cartridge with 5 mL phosphate buffer (7 g Na2HPO.r2H20: 6 g NaCI in 1 L water) in fractions of 1 mL, yielding 204 MBq (2S)-2- amino-5-[4-(fluoromethoxy)benzyl]hexanedioic acid ([18F]-41 isomer C5-2) in 1 mL buffer (fraction 3). Radiochemical purity was determined to be >99% (tR = 2.9 min, analytical HPLC method C; tR = 20.6, analytical HPLC method G). Example 44
Figure imgf000225_0001
4-[2-{benzyloxy)ethoxy]-3-hydroxybenzaldehyde
Figure imgf000225_0002
A solution of commercially available 3,4-dihydroxybenzaldehyde (17.04 g, 123.7 mmol) in 150 ml DMF and 14.9 g (107.5 mmol) potassium carbonate was stirred at 60 °C for 4 hours. 30.8 g (14.2 mmol) [(2-bromoethoxy)methyl]benzene was added at room temperature. The reaction mixture was stirred over night. The volume of the reaction mixture is reduced to half volume in vacuo. Aqueous saturated ammonium chloride solution and ethyl acetate is added to the reaction mixture. The organic phase is separated, washed twice with saturated aqueous sodium chloride solution, dried with magnesium sulfate filtered and concentrated in vacuo. The crude product is purified by column chromatography (silica gel, hexane / ethylacetate gradient: 7:1 - 1 :2). The desired product was obtained in 22.2% yield (8.27g, 27.3 mmol).
Ή NMR (300 MHz, CHLOROFORM-d) δ ppm 3.85 (dd, 2 H) 4.28 (dd, 2 H) 4.62 (s, 2 H) 6.23 (s, 1 H) 6.99 (d, 1 H) 7.34 - 7.44 (m, 7 H) 9.84 (s, 1 H)
LC-MS (ESI) = tvT+1 (60) 272, -> 1.08 min b 4-[2-{benzyloxy)ethoxy]-3-fert-butoxybenzaldehyde
Figure imgf000225_0003
To a stirred solution of 2.95 g (10.8 mmol) 4-[2-(benzyloxy)ethoxy]-3- hydroxybenzaldehyde in 20 ml toluene was added 17.6 g (86. mmol) 1 ,1-di-fert-butoxy- Λ/./V-dimethylmethanamine drop by drop. The reaction mixture was stirred at room temperature over night. The reaction mixture is diluted with dichloromethane, washed with aqueous sodium hydroxide solution (1 N), dried with sodium sulfate and concentrated in vacuo. The crude product is purified by column chromatography (silica gel, hexane / ethylacetate gradient: 7:1 - 1 :99). The desired product was obtained in 43% yield (8.27g, 27. mmol).
Ή NMR (400 MHz, CHLOROFORM-d) δ ppm 1.38 (s, 9 H) 3.90 (dd, J=5.31 , 4.29 Hz, 2 H) 4.19 - 4.27 (m, 2 H) 4.64 (s, 2 H) 7.00 (d, J=8.34 Hz, 1 H) 7.27 - 7.34 (m, 1 H) 7.34 - 7.39 (m, 4 H) 7.48 - 7.64 (m, 2 H) 9.84 (s, 1 H)
LC-MS (ESI) = M+ + 1 , 329, (95) c 4-[2-{benzyloxy)ethoxy]-3-fert-butoxyphenyl}methanol
Figure imgf000226_0001
To a stirred mixture of 1.00 g (26.5 mmol) sodium borohydride in 80 ml THF was added 2, .9 g (8.83 mmol) 4-[2-(benzyloxy)ethoxy]-3-fert-butoxybenzaldehyde diluted in 40 ml THF drop by drop. The reaction mixture was stirred for 10 min. Methanol (5.8 ml) was added to this mixture drop by drop. The reaction mixture was stirred for 2 hours and poured onto ~ 200 ml stirred ice-cooled saturated aqueous ammonium chloride solution. The solution was extracted trice with dichloromethane. The combined organic phases were dried with sodium sulfate and concentrated in vacuo. The crude product was used in the following reaction without further purification.
H NMR (300 MHz, CHLOROFORM-d) δ ppm 1.35 (s, 9 H) 3.81 - 3.91 (m, 2 H) 4.09 - 4.21 (m, 2 H) 4.54 - 4.62 (m, 2 H) 4.63 (s, 2 H) 6.85 - 6.92 (m, 1 H) 6.98 - 7.02 (m, 1 H) 7.03 (s, 1 H) 7.27 - 7.34 (m, 2 H) 7.34 - 7.41 (m, 3 H)
LC-MS (ESI): M++18 (50), 1.27 min d) 1 -[2-{benzyloxy)ethoxy]-4-{bromomethyl)-2-fert-butoxybenzene
Figure imgf000227_0001
To a stirred solution of 0.9 g (2, .2 mmol) {4-[2-(benzyloxy)ethoxy]-3-fert- butoxyphenyl}methanol and 976 mg (2.94 mmol) tetrabromo methane in 9 ml THF was added 775 mg (2.96 mmol) triphenylphosphin diluted in 4.5 ml THF at 0 °C dropwisly. The reaction mixture was stirred for 1 h at 0 °C. The suspension was filtrated. The filter cake was washed with THF. The combined filtrates were concentrated in vacuo. The crude product is purified by column chromatography (silica gel, hexane / ethylacetate gradient: 99: 1 - 1 :99). The desired product was obtained in 28% yield (313 mg, 0.76 mmol).
1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1 .36 (s, 9 H) 3.80 - 3.91 (m, 2 H) 4.09 - 4.21 (m, 2 H) 4.46 (s, 2 H) 4.63 (s, 2 H) 6.81 - 6.89 (m, 1 H) 6.99 - 7.09 (m, 2 H) 7.27 - 7.34 (m, 1 H) 7.35 - 7.40 (m, 3 H) e) di-ferf-butyl (4S)-4-{4-[2-(benzyfoxy)et oxy]-3-fert-butoxybenzyS}-W-(ierf-
Figure imgf000227_0002
To a solution of 327 mg (0.91 mmol) di-ferf-butyl /V-(ferf-butoxycarbonyl)-L-glutamate in 10 ml THF was added 2 ml (2 mmol) lithium bis(trimethylsilyl)amide solution in THF drop by drop at -78 °C. The reaction mixture was stirred for 2 hours. 300 mg (0.76 mmol) 1 -[2-(benzyloxy)ethoxy]-4-(bromomethyl)-2-ferf-butoxybenzene in 2 ml THF were added at -78 °C. The reaction mixture was stirred for 2 hours. 4.5 ml aqueous hydrogen chloride solution (2N) is added drop by drop. The solution was allowed to be warmed to room temperature. The solution was extracted repeatedly with dichloro methane. The combined organic phases were washed with water, dried with sodium sulfate and concentrated in vacuo. The crude product is purified twice by column chromatography (silica gel, hexane / ethylacetate gradient: 7: 1 - 1 : 1 ). The desired product was obtained in 48.7% yield (358mg, 0.45 mmol).
H NMR (300 MHz, CHLOROFORM-d) δ ppm 1 .31 (s, 9 H) 1 .33 (s, 9 H) 1 .43 (s, 9 H) 1.44 (s, 9 H) 1 .87 (t, J=7.72 Hz, 2 H) 2.53 - 2.68 (m, 1 H) 2.75 (d, J=6.78 Hz, 2 H) 3.80 - 3.89 (m, 2 H) 4.09 - 4.17 (m, 2 H) 4.25 - 4.40 (m, 1 H) 4.62 (s, 2 H) 4.88 (d, J=9.04 Hz, 1 H) 6.80 (s, 2 H) 6.83 (s, 1 H) 7.28 - 7.44 (m, 5 H)
LC-MS (ESI): M++1 , 672 (30), -> 1 .81 min f) di-fert-butyl (4S)-N-(ferf-but©xyearbonyl)-4-[3-fert-butoxy-4-(2-
Figure imgf000228_0001
To a solution of 340 mg (0.506 mmol) di-fert-butyl (4S)-4-{4-[2-(benzyloxy)ethoxy]-3- terf-butoxybenzyl}-A -(terf-butoxycarbonyl)-L-glutamate in 5 ml methanol was added a little amount of palladium on carbon. The solution is stirred in hydrogen atmosphere for 4 hours. The reaction mixture is filtrated. The filtrate is concentrated. The crude product is concentrated in vacuo. The crude product (310 mg) was used in the following reaction without further purification.
Ή NMR (400 MHz, CHLOROFORM-d) δ ppm 1 .32 (s, 9H) 1 .35 (s, 9H) 1 .44 (s, 9H) 1.45 (s, 9H) 1 .85-1 .88 (m, 2H) 2.55 - 2.67 (m, 1 H) 2.68 - 2.85 (m, 2 H) 2.93 (br. s., 1 H) 3.49 (br. s., 4 H) 3.74 - 3.85 (m, 2 H) 4.01 - 4.10 (m, 2 H) 4.18 (d, J=7.83 Hz, 1 H) 4.89 (d, J=8.34 Hz, 1 H) 6.76 - 6.93 (m, 3 H)
LC-MS (ESI): M++1 , 582 (100), 1 .56 min
g) di-fert-butyl (4S)-N-<fert-butoxycarbonyl)-4-[3-fert-butoxy-4-{2- fluoroethoxy)benzyl]-L-glutamate
Figure imgf000229_0001
To a stirred solution of 64 mg (0.1 1 mmol) di-fert-butyl (4S)-N-(ferf-butoxycarbonyl)-4- [3-iert-butoxy-4-(2-hydroxyethoxy)benzyl]-L-glutamate in 0.5 ml THF was added 102.7 mg (0.34 mmol) nonafluoro 1 -butanesulphonic acid fluoride, 54.8 mg (0.34 mmol) triethylamine trihydrofluoride and 102 mg (1 .01 mmol) triethyl amine. The reaction mixture is stirred for 3 days. Further 34 mg (0.1 1 mmol) nonafluoro 1 -butanesulphonic acid fluoride, 18 mg (0.1 1 mmol) triethylamine trihydrofluoride and 34 mg (0.33 mmol) triethyl amine were added. The reaction mixture is stirred for 3 hours and is concentrated in vacuo. The crude product is purified by column chromatography (silica gel, hexane / ethylacetate gradient: 12: 1 - 1 : 1 ). The desired product was obtained in 37.4 % yield (64.2 mg, 0.04 mmol).
H NMR (400 MHz, CHLOROFORM-d) δ ppm 1 .29 - 1 .33 (m, 9 H) 1 .34 (s, 9 H) 1 .44 (s, 9 H) 1 .48 (s, 9 H) 1 .88 (t, 2 H) 2.57 - 2.66 (m, 1 H) 2.69 - 2.85 (m, 2 H) 4.18 (br. s., 1 H) 4.22 (dd, 1 H) 4.64 - 4.70 (m, 1 H) 4.76 - 4.82 (m, 1 H) 4.89 (d, 1 H) 6.76 - 6.89 (m, 3 H) -hydroxybenzyi]-L-glutamic acid
Figure imgf000229_0002
A solution of hydrogen chloride in dioxane (0.25 ml, 4M) is added to 24 mg (0.041 mmol) di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-[3-feni-butoxy-4-(2- fluoroethoxy)benzyl]-L-glutamate. The reaction mixture is stirred for 4 hours and stored at -25 °C over night. The reaction mixture is concentrated in vacuo. Ca. 3 ml dichloro methane is added and the solution is concentrate in vacuo. The last step is repeated. The crude product is purified by HPLC (column, XBrigde, C18, 5pm 100x30 mm, H20 + 0, 1 % trifluoroacetic acid, acetonitrile, flow 38 mL/min). 1H N R (400 MHz, DEUTERIUM OXIDE) δ ppm 1 .90 - 2.05 (m, 1 H) 2.06 - 2.17 (m, 1 H) 2.81 - 2.92 (m, 2 H) 2.94 - 3.06 (m, 1 H) 3.80 (dd, 1 H) 4.24 - 4.32 (m, 1 H) 4.33 - 4.40 (m, 1 H) 4.83 - 4.91 (m, 1 H) 6.79 (dd, 1 H) 6.83 (d, 1 H) 6.98 - 7.01 (m, 1 H) 19F NMR (376 MHz, DEUTERIUM OXIDE) δ ppm -75.42 (s, 1 F)
Example 45
di-fert-butyl (4S)-N-(tert-butoxvcarbonvl)^-(3-fert-butoxy^-(2-
Figure imgf000230_0001
To a stirred solution of 100 mg (0.172 mmol) di-fert-butyl (4S)-N-(fert-butoxycarbonyl)-4- [3-fert-butoxy-4-(2-hydroxyethoxy)benzyl]-L-glutamate, 25.6 mg (0.253 mmol) triethylamine in ca. 1 ml dichloromethane was added 25.5 mg (0.222 mmol) methane suiphonic acid chloride at 0 °C. The reaction mixture was stirred at room temperature for 4 hours. Further 25.6 mg (0.253 mmol) triethylamine and 25.5 mg (0.222 mmol) methane suiphonic acid chloride were added. The reaction mixture is stirred for another 4 hours. The reaction mixture is diluted with dichloro methane. The organic phase washed with saturated aqueous ammonium chloride, saturated aqueous sodium hydrogen carbonate solution, dried with sodium sulfate and concentrated in vacuo. The crude product is purified by column chromatography (silica gel, hexane / ethylacetate gradient: 5: 1 - 1 :99). The desired product was obtained in 79.6% yield (99 mg, 0, 14 mmol).
NMR (400 MHz, CHLOROFORM-d) δ ppm 1 .33 (s, 9 H) 1 .34 - 1 .38 (m, 9 H) 1 .44 (s, 9 H) 1 .45 (s, 9 H) 1 .87 (t, 2 H) 2.55 - 2.67 (m, 1 H) 2.71 - 2.84 (m, 2 H) 3.12 (s, 3 H) 4.14 - 4.19 (m, 1 H) 4.19 - 4.24 (m, 2 H) 4.50 - 4.61 (m, 2 H) 4.89 (d, 1 H) 6.73 - 6.90 (m, 3 H)
LC-MS (ESI): M++1 , 660, (35), -» 1 .60 min
Example 46 18F1fluoroethoxY)-3-hYdroxYbenzYll-L-qlutamic acid
Figure imgf000231_0001
[18F]Fluoride (1092 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Acceil Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 ml_). 5 mg of di-tert-butyl (4S)-N-(teri-butoxycarbonyl)-4-(3-tert- butoxy-4-{2-[(methylsulfonyl)oxy]ethoxy}benzyl)-L-glutamate in 1 ml_ acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt, 2M HCI (1 ml.) was added and the mixture was stirred at 120 °C for 10 min. The crude product was diluted with 30 ml_ water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 ml_ water (pH 2) and 30 ml_ ethanol. The cartridge was eluted with 5 ml_ phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water) yielding 208 MBq (40% d.c.) 4-[4-(2-[18F]fluoroethoxy)-3-hydroxybenzyl]-L-glutamic acid ([18F]-44) in a fraction of 1 ml buffer. Radiochemical purity was determined to be >99% (tR = 2.7 min, analytical HPLC method C).
Example 47
(4S)-4-r4-Hvdroxvbenzyl1-L-qlutamic acid
Figure imgf000231_0002
To 0.35 g (0.75 mmol) of di-fert-butyl (4S)- V-(ferf-butoxycarbonyl)-4-(4-hydroxybenzyl)- L-glutamate were added 10 mL of trifluoro acetic acid and the solution was stirred for 2 days at room temperature. The excess of trifluoro acetic acid was evaporated and the residue was taken up three times in tetrahydrofuran and then evaporated. The resulting oil was chromatographed on C-18 reversed phase silica gel using a water/acetonitrile gradient, the appropriate fractions were combined and concentrated. Yield: 145 mg (76.3%)
1H-NMR (400 MHz, DIMETHYLSULFOXIDE-d6): δ [ppm]= 1.64-1 .68 (m, 2H), 2.38-2.43 (m, 1 H), 2.78-2.87 (m, 2H), 3.44-3.49 (m, 1 H). 6.63-6.66 (d, 2H), 6.94-6.96 (d, 2H). ESI+ m/z 254 (M+H).
Example 48
(4SW4Jj 8F)fluoromethoxylben^
Figure imgf000232_0001
[18F]-48
[18F]Fluoride (15000 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accell Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vessel 1 . The mixture was dried under gentle nitrogen stream at 120 "C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 100 pL dibromo methane in 0.9 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 130 °C for 5 min. The reaction vessel 1 was colled to 50 °C and bromo [18F]fluoromethane was distilled through 4 silica cartridges (Silica plus, Waters) into reaction vessel 2 containing 1000 pL DMSO.
800 pL of the solution of bromo [ ,F]fluoromethane in DMSO were mixed with 2.1 mg (4S)-4-[4-Hydroxybenzyi]-L-glutamic acid, 200 pL water and 10 pL NaOH (10%). The resulting mixture was heated at 1 10 °C for 5 min. After cooling to rt, the crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, waters). The cartridge was washed with 10 mL water (pH 2) and the activity was etuted with 1 mL fractions ethanol. Fractions 1 and 2 were combined (470 MBq), dilute with 30 mL water (pH 2) and passed through a Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with ethanol (20 mL) and the activity was eluted with 1 mL fractions phosphate buffer (7 g Na2HPG 2H20; 6 g NaCI in 1 L water) yielding 344 MBq ((4S)-4-{4-[(18F)fluoromethoxy]benzyl}-L-glutamic acid ([ 8F]-48) in 1 ml buffer (fraction 3). Radiochemical purity was determined to be >99% (tR = 2.7 min, analytical HPLC method C; tR = 14.7, analytical HPLC method G). Example 49
(4ft)-4-r4-Hvdroxvbenzyl1-L-qlutamic acid
Figure imgf000233_0001
a) di-fert-butyl 4-[4-{benzyloxy)benzyl]-W-trityl-L-glutamate
Figure imgf000233_0002
Di-fert-butyl /V-trityl-L-glutamate (1 .63 g, 3.25 mmol) was dissolved in tetrahydrofuran (12 ml) and the solution was cooled to -78 °C. To the solution was added lithium 1 , 1 , 1 ,3,3,3-hexamethyldisilazide (1 M in tetrahydrofuran, 7.14 ml) and, after stirring at - 78 °C for 20 min, benzyl 4-(bromomethyl)phenyl ether (1 .08 g, 3.90 mmol) in tetrahydrofuran (8 ml) was slowly added. The cooling bath was removed and the reaction mixture was stirred for 2 h. Then, 50 ml of 2 aqueous hydrogen chloride solution were added and the mixture was extracted with dichloromethane. The organic phase was dried and concentrated under reduced pressure; the residue was purified by silica gel column chromatography to yield 813 mg (30%) of the product.
MS (ESI*): m/e = 698.3 (M + H+).
The material is a mixture of diastereomers. yl)-L-glutamate
Figure imgf000233_0003
Di-fe/f-butyl 4-[4-(benzyloxy)benzyl]-/V-trityl-L-glutamate (499 mg, 0.72 mmol) were dissolved in methanol (20 ml). Palladium (10% on charcoal) (228 mg; 214 μπιοΙ) was added and the suspension was shaken under a hydrogen atmosphere for 12 h. The reaction mixture was filtered through a pad of celite, concentrated under reduced pressure and the residue was purified by silica gel column chromatography to yield 75 mg (28.7%) of the product.
MS (ESI+): m/e = 366.1 (M + hT ). The material is a mixture of diastereomers. l)-L-glutamic acid
Figure imgf000234_0001
Di-tert-butyl 4-(4-hydroxybenzyl)-L-glutamate (27 mg, 58pmol) was dissolved in trifluoroacetic acid (1 ml) and stirred at room temperature for 2 h. The mixture was then taken up in toluene and concentrated under reduced pressure. The residue was purified by preparative HPLC (RP-18; solvents: acetonitrile (+0.1 % trifluoroacetic acid), water (+0.1 % trifluoroacetic acid): gradient: 30% -> 40% acetonitrile (20 min)).
Two separate diastereomers of 4-(4-hydroxybenzyl)-L-glutamic acid were isolated:
Figure imgf000234_0002
'analytical HPLC (RP-18; solvents: acetonitrile (+0.1 % trifluoroacetic acid), water (+0.1 % trifluoroacetic acid); gradient: 30% -> 40% acetonitrile (20 min))
The major isomer was isolated in 1 1.4 mg (77%) yield. MS (ESI' ): m/e = 254.1 (M + H+). Ή-N R (400MHz, DMSO-d6): δ [ppm]= 1 .56 - 1 .81 (m. 2H). 2.62 - 2.87 (m. 3H). 3.50 - 3.59 (m, 1 H, overlaps with strong water signal), 6.65 (d, 2H), 6.96 (d, 2H), 9.05 - 9.30 (m, 1 H). Example 50
Figure imgf000235_0001
[18F]-50
p8F]Fluoride (16000 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vessel 1 . The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 100 pL dibromo methane in 0.9 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 130 "C for 5 min. The reaction vessel 1 was colled to 50 °C and bromo [18F]fluoromethane was distilled through 4 silica cartridges (Silica plus, Waters) into reaction vessel 2 containing 1000 pL DMSO.
500 pL of the solution of bromo [18F]fluoromethane in DMSO were mixed with 2.1 mg (4R)-4-[4-Hydroxybenzyl]-L-glutamic acid, 200 pL water, 300 pL DMSO and 10 pL NaOH (10%). The resulting mixture was heated at 1 10 °C for 5 min. After cooling to rt, the crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, waters). The cartridge was washed with 10 mL water (pH 2) and the activity was etuted with 1 mL fractions ethanoi. Fractions 1 and 2 were combined (209 MBq), dilute with 30 mL water (pH 2) and passed through a Strata- X-C cartridge (200 mg, Phenomenex). The cartridge was washed with ethanoi (20 mL) and the activity was eluted with 1 mL fractions phosphate buffer (7 g Na2HPO -2H20; 6 g NaCI in 1 L water) yielding 102 MBq ((4R)-4-{4-[(18F)fluoromethoxy]benzyl}-L-glutamic acid ([18F]-50) in 1 ml buffer (fraction 4). Radiochemical purity was determined to be >99% (tR = 2.8 min, analytical HPLC method C).
Example 51
Figure imgf000236_0001
a) 4-benzvl 1.4-di-tert-butvl (1 S.4S)-1 -r(tert-butoxvcarbonvnamino1-5-(4-
Figure imgf000236_0002
Di-tert-butyl (5S)-2-(benzyloxycarbonyl)-5-[(tert-butoxycarbonyl)amino]hexanedioate (1 g, 1 .970 mmol) was dissolved in DMF (20 ml) and sodium hydride (53 mg, 1 .773 mmol) was added. After stirring for 60 min, a solution of 4-nitrobenzyl bromide (426 mg, 1.970 mmol) in 10 ml DMF was added and the mixture was stirred at 60 °C for 90 min. The mixture was then concentrated in vacuo, the residue was taken up in water (50 ml) and ethyl acetate (100 ml), and the organic phase was washed with brine (3 x 50 ml), dried over magnesium sulfate and concentrated in vacuo. The crude product was chromatographed over silica gel (hexane, ethyl acetate) to yield 1 .04g (82%) of a clear oil.
MS (ESI' ): m/e = 643.2 (M + H' ). bj (5S)-2-(4-aminobenzyI}-6 ert^toxy-2-(tert^ui^c^boriyS)-5- (tert-
Figure imgf000237_0001
4-benzyl 1 ,4-cSi-tert-buiyl (1 S,4S)-1 -[(tert-butoxycarbonyl)amino]-5-(4-nitrophenyl)- pentane-1.4,4-tricarboxylate (1 .04 g, 1 .618 mmol) were dissolved in methanol (20 ml). Palladium (10% on charcoal) (52 mg) was added and the suspension was shaken under a hydrogen atmosphere for 12 h. The catalyst was filtered off, the residue was concentrated in vacuo, and the product was obtained as white foam (864 mg, quant. ). MS (ESI' ): m/e = 523.2 (M + H+). c) Di-tert-butyl (5S)-2-(4-aminobenzyl)-5-r(tert-
Figure imgf000237_0002
(5S)-2-(4-aminobenzyl)-6-tert-butoxy-2-(tert-butoxycarbonyl)-5-[(tert-butoxycarbonyl)- amino]-6-oxohexanoic acid (846 mg, 1 .618 mmol) were dissolved in dioxane (25 ml). 4- (dimethylamino)pyridine (413 mg, 3.383 mmol) were added and the mixture was refluxed for 6 h. The mixture was concentrated in vacuo and the residue was chromatographed on silica gel (hexane/ethyl acetate) to yield 670 mg (87%) of a slightly yellow oil.
MS (ESI*): m/e = 479.2 (M + H+). dipi-tert-butyl l5S)-2-(4^[2jjbenzy^^
butox^rbonyl)aminol|^anedioate
Figure imgf000238_0001
Di-tert-butyl (5S)-2-(4-aminobenzyl)-5-[(tert-butoxycarbonyl)amino]hexanedioate (670 mg, 1 .40 mmol) was dissolved in 1 ,2-dichloroethane (10 ml) and benzyloxyacetaldehyde (210 mg, 1 .40 mmol) and sodium triacetoxyborohydride (415 mg, 1 .96 mmol) were added. The mixture was stirred at room temperature for 4 h and then poured on 10 ml 1 N aqueous sodium hydrogen carbonate solution. The aqueous phase was extracted with dichioromethane (2 x 10 ml) and the organic phases were washed with water (30 ml), dried over magnesium sulfate and concentrated in vacuo. Flash chromatography on silica gel (hexane, ethyl acetate) gave the product as slightly yellow oil (853 mg, 99%).
MS (ESI' ): m/e = 613.3 (M + H*).
Figure imgf000238_0002
Di-tert-butyl (5S)-2-(4-{[2-(benzyloxy)ethyl]amino}benzyl)-5-[(tert-butoxycarbonyl)- aminojhexanedioate (853 mg, 1 .39 mmol) was dissolved in dichioromethane (10 ml) and added slowly to a solution of di-tert-butyldicarbonate (608 mg, 2.78 mmol) in 10 ml dichioromethane. The mixture was stirred at room temperature for 2 d. The mixture was then concentrated and the residue was subjected to chromatography on silica gel (hexane, ethyl acetate) to yield 80 mg (8%) of a colourless oil.
MS (ESI*): m/e = 713.5 (M + H' ). f) Di-tert-butyl (2S)-2-r(tert-butoxYcarbonYl)amino1-5-{4-r(tert-butoxYcarbonYl)(2-
Figure imgf000239_0001
Di-tert-butyl (5S)-2-(4-{[2-(benzyloxy)ethyl](tert-butoxycarbonyl)amino}benzyl)-5-[(tert- butoxycarbonyl)amino]hexanedioate (78 mg, 1 10 μιτιοΙ) were dissolved in 10 ml methanol. Palladium (10% on charcoal) (15 mg) was added and the suspension was shaken under a hydrogen atmosphere for 27 h. The catalyst was filtered off, the residue was concentrated in vacuo to yield 65 mg (95%) of the product.
MS (ESI*): m/e = 623.4 (M + H' ).
Figure imgf000239_0002
f(methvlsulfonvl)oxvlethvl)aminolbenzyl>hexanedioate
Figure imgf000240_0001
Di-tert-butyl (2S)-2-[(teri-butoxycarbonyl)amino]-5-{4-[(tert-butoxycarbonyl)(2-hydroxy- ethyi)amino]benzyl}hexanedioate (30 mg, 48 μητιοΙ) was dissolved in 1 ml dichloromethane. The solution was cooled to 0 °C and triethylamine (200 μΙ, 1 .43 mmol) and methanesulfonyl chloride (30 μΙ, 387 μηιοΙ) were slowly added. The mixture was stirred at 0 °C for 2 h and then for additional 12 h, while the temperature was allowed to rise to room temperature. The mixture was then concentrated in vacuo and the residue was chromatographed on silica gel (hexane, ethyl acetate) to give 10 mg (29%) of the mesylate.
MS (ESI+): m/e = 701 .5 (M + H+).
Example 52
(2S)-2-amino-5-(4-{f2-(18F)fluoroethvllamino)benzvl)hexanedioic acid
Figure imgf000240_0002
[18F]-52
[18F]Fluoride (2775 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 ml_). 5 mg of di-tert-butyl (2S)-2-[(tert-butoxycarbonyl)amino]-5-{4- [(tert-butoxycarbonyl){2-[(methylsulfonyl)oxy]ethyl}amino]benzyl}hexanedioate in 1 ml_ acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt, 0.5 mL of the mixture were treated with 2M HCI (0.5 mL) and stirred at 100 °C for 10 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 1 ) and 10 mL ethanol. The cartridge was eluted with 5 mL phosphate buffer (7 g Na2HPO.'.-2H20; 6 g NaCI in 1 L water) yielding 19 MBq (2S)-2-amino-5-(4-{[2-(18F)fluoroethyl]amino}benzyl)hexanedioic acid ([18F]-52) in a fraction of 1 ml buffer. Radiochemical purity was determined to be >99% (tR = 2.9 min, analytical HPLC method F).
Example 53
di-ferf-butyl (2S)-2-r(tert-butoxYcarbonYl)amino1-5-(4-{r(4S,5S)-2,2-climethYl-5-({r(4- methvlphenvl)sulfonylloxv)methvH-1 ,3-dioxolan-4- vnmethoxv)benzyl)hexanedioate
Figure imgf000241_0001
500 mg (1 .04 mmol) (2S)-2-fert.-Butoxycarbonylamino-5-(4-hydroxy-benzyl - hexanedioic acid di-fert. -butyl ester, 144 mg (1 .04 mmol) potassium carbonate and 491 mg (1.04 mmol) [(4S.5S)-2,2-dimethyl-1 ,3-dioxolane-4,5-diyl]bis(methylene) bis(4- methylbenzenesulfonate) in 12 mL DMF were heated in a microwave at 100 °C for 2 h. Brine (300 mL) was added and the mixture was extracted with dichloromethane (3 x 100 mL). The combined organic fractions were dried over sodium sulfate and concentracted. The crude product was purified by Flash chromatography (Silica, 2-40% ethyl acetate in hexane) to afford 430 mg (52%) di-fert-butyl (2S)-2-[(tert- butoxycarbonyl)amino]-5-(4-{[(4S,5S)-2,2-dimethyl-5-({[(4- methylphenyl)sulfonyl]oxy}methyl)-1.3-dioxolan-4-yl]methoxy}benzyl)hexanedioate. 1H-NMR (400 MHz, CHLOROFORM-d): δ [ppm]= 1 .32-1 .68 (m, 19H), 1 .71-1 .85 (m, 1 H), 2.44 (s, 3H). 2.46-2.66 (m, 2H), 2.78-2.87 (m, 1 H). 3.94 (dd, 1 H), 4.06-4.29 (m, 6H), 5.03 (br. s, 1 H), 6.74 (d, 2H). 7.06 (dd. 2H), 7.33 (d, 2H), 7.80 (d, 2H).
ES+ m/z 778 (M+H), 800 (M+Na).
Example 54
(2S)-2-amino-5-(4-{r(2S,3/?)-4-{18F)fluoro-2,3-
Figure imgf000242_0001
[18F]-54
[18F]Fluoride (850 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Acceii Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg of di-tert-butyl (2S)-2-[(tert-butoxycarbonyl)amino]-5-(4- {[(4S,5S)-2,2-dimethyl-5-({[(4-methylphenyl)sulfonyl]oxy}methyl)-1 ,3-dioxolan-4- yl]methoxy}benzyl)hexanedioate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt 2M HCI (1 mL) and stirred at 120 °C for 10 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPO_-2H20; 6 g NaCI in 1 L water) yielding 74 MBq (22%, d.c.) (2S)-2-amino-5-(4-{[(2S.3R)-4-(18F)fluoro-2,3- dihydroxybutyl]oxy}benzyl)hexanedioic acid ([18F]-54) in a fraction of 1 ml buffer (fraction 3). Radiochemical purity was determined to be >99% (tR = 2.6 min, analytical HPLC method C).
Example 55 di-ferf-butyl (4S)-N-(tert-butoxYcarbonYl)-4-{2,3-dihYdrori ,31oxaZolor3,2-alpYridin- -ium-6-ylmethyl)-L-qlutamate 4-methylbenzenesulfonate
Figure imgf000243_0001
Di-feri-butyl (4S)-N-(te -buioxycarbonyl)-4-{[6-(2-hydroxyeihoxy)pyridin-3-yl]meihyl}-L- giutamate (88 mg, 0.17 mmol) was dissolved in dichloromethane (10 mL) and treated with 2,6-lutidine (28 mg, 0.26 mmol) and p-toluenesulfonic anhydride (84 mg, 0.26 mmol). The mixture was stirred at room temperature over night, concentrated and purified by RP-HPLC (70-30% water (0.1 % HCOOH) in acetonitrile).
81 mg (57%) di-iert-butyl (4S)-N-(te/t-butoxycarbonyl)-4-(2,3-dihydro[1 ,3]oxazolo[3,2- a]pyridin-4-ium-6-ylmethyl)-L-glutamate 4-methylbenzenesulfonate were obtained.
1H-N R (400 MHz, CHLOROFORM-d): δ [ppm]= 1.32-2.00 (m, 30H), 2.33 (s, 3H), 2.87-3.08 (m, 2H), 4.10-4.23 (m, 1 H), 5.18-5.31 (m, 3H), 5.31-5.49 (m, 2H), 7.08-7.17 (m, 3H), 7.71 (d, 2H), 8.10-8.14 (m, 1 H), 8.76 (s, 1 H).
Example 56
Figure imgf000243_0002
[ 8F]-56
[18F]Fluoride (2702 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg di-fert-butyl (4S)-A/-(tert-butoxycarbonyl)-4-(2,3- dihydro[1 ,3]oxazolo[3,2-a]pyridin-4-ium-6-ylmethyl)-L-glutamate 4- methylbenzenesulfonate in 1 ml_ acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 "C for 10 min. After cooling to rt 2M HCI (1 mL) and stirred at 120 °C for 5 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 40 mL water (pH 2) and 30 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPO. 2H20; 6 g NaCI in 1 L water) yielding 338 MBq (21 %, d.c.) 4-({6-[2-( 8F)fluoroethoxy]pyridin-3-yl}methyl)-L- glutamic acid ([18F]-56) in a fraction of 1 ml buffer (fraction 3). Radiochemical purity was determined to be >99% (tR = 2.7 min, analytical HPLC method F).
Example 57
di-ferf-butyl (4S)-N-(tert-butoxYcarbonYl)^-(4-{r(4S15S)-212-dimethYl-5-({r(4- methvlphenvl)sulfonvlloxv)methvl)-1 ,3-dioxolan-4-vllmethoxv>benzyl)-L- glutamate
Figure imgf000244_0001
To 0.47 g (1 mmol) (4S)-/V-(fert-butoxycarbonyl)-4-(4-hydroxybenzyl)-L-glutamate and 0.47 g (1 mmol) [(4S,5S)-2.2-dimethyl-1 ,3-dioxolane-4.5-diyl]dimethanediyl bis(4- methylbenzenesulfonate) in 15 mL DMF was added potassium carbonate (0.28 g, 2 mmol). The mixture was heated in a microwave for 2 h at 100 °C. Water was added and the mixture was extracted with dichloromethane. The organic phase was dried over sodium sulfate, filtered and concentrated. The crude product was purified by flash chromatography (silica, 20% ethyl acetate in hexane) to afford 0.25 g (33%) di-fert-butyl (4S)-N-(tert-butoxycarbonyl)-4-(4-{[(4S.5S)-2,2-dimethyl-5-({[(4- methylphenyl)sulfonyl]oxy}methyl)-1 ,3-dioxolan-4-yl]methoxy}benzyl)-L-glutamate.
1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .31 (s, 9H), 1 .37 - 1 .53 (m, 23H), 1.87 (t, 2H), 2.44 (s, 3H), 2.61 (quin, 1 H), 2.81 (br. d, 2H), 3.92 - 3.97 (m, 1 H), 4.06 - 4.29 (m, 7H), 4.88 (d, 1 H), 6.74 (d, 2H), 7.08 (d, 2H), 7.33 (d, 2H), 7.80 (d, 2H). Example 58
18F)fluoro-2,3-dihYdroxYbutYlloxY}benzYl)-L-qlutamic acid
Figure imgf000245_0001
[18F]Fluoride (3565 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Acceii Pius QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg di-fert-butyl (4S)-N-(tert-butoxycarbonyl)-4-(4-{[(4S,5S)-2,2- dimethyl-5-({[(4-methylphenyl)sulfonyl]oxy}methyl)-1 ,3-dioxolan-4-yl]methoxy}benzyl)-L- glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 °C for 10 min. After cooling to rt 2M HCI (1 mL) and stirred at 120 °C for 10 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanoi. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HP04-2H20; 6 g NaCI in 1 L water) yielding 545 MBq (23%, d.c.) 4-(4-{[(2S,3f?)-4-(18F)fluoro-2,3-dihydroxybutyl]oxy}benzyl)-L-glutamic acid ([18F]-58) in a fraction of 2 ml buffer (fraction 1 +2). Radiochemical purity was determined to be >99% (tR = 2.6 min, analytical HPLC method C).
Example 59
djdter butyl (4S) N-ftert-butoxYcarbonyllzj^^
mejhylphenvl)sulfonyllc ( lg!^^
Figure imgf000246_0001
To 0.93 g (2 mmol) (4S)-A/-(fert-butoxycarbonyl)-4-(4-hydroxybenzyl)-L-glutamate and 1 .34 g (4 mmol) c;s-2-phenyl-1 ,3-dioxan-5-yl 4-methylbenzenesulfonate in 18 ml_ was added potassium carbonate (0.55 g, 4 mmol). The mixture was heated in a microwave for 2 h at 100 °C. Water was added and the mixture was extracted with ethyl acetate. The organic phase was dried over sodium sulfate, filtered and concentrated. The crude product was purified by flash chromatography to afford 0.165 g (13%) di-fert-butyl (4S)- N-(tert-butoxycarbonyl)-4-{4-[(trans-2-phenyl-1 ,3-dioxan-5-yl)oxy]benzyl}-L-glutamate. The benzylidene protected derivative (0.13 g, 0.2 mmoL)) was dissolved in methanol (15 ml.) Palladium/C (10% Pd) was added and the mixture was stirred under hydrogen atmosphere over night. The mixture was filtered and the solvent was evaporated, yielding 0.1 1 g (100%) di-fert-butyl (4S)-N-(tert-butoxycarbonyl)-4-{4-[(1 ,3- dihydroxypropan-2-yl)oxy]benzyl}-L-glutamate.
The dihydroxy derivative (0.1 1 g, 0.2 mmol) was dissolved in dichloromethane (19 mL). Pyridiene (100 μΙ_) and 4-methylbenzenesulfonyl chloride (38 mg, 0.2 mmol) were added at 0 "C. The mixture was stirred for 2.5 h. The crude product was purified by flash-chromatography (silica, dichloromethane/methanol) yielding 55 mg (40%) di-fert- butyl (4S) N-(tert-butoxycarbonyl)-4-{4-[(1-hydroxy-3-{[(4- methylphenyl)sulfonyl]oxy}propan-2-yl)oxy]benzyl}-L-glutamate. H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .32 (s, 9H), 1 .38 - 1.98 (m, 20H), 1.87 (t, 2H), 2.45 (s, 3H), 2.60 (quin, 1 H), 2.72-2.89 (m, 2H), 3.74 - 3.90 (m, 2H), 4.09 - 4.29 (m, 3H), 4.45 (mc, 1 H), 4.89 (d, 1 H), 6.74-6.81 (m, 2H), 7.03-7.10 (m, 2H), 7.33 (d, 2H), 7.77 (d, 2H).
Example 60
4J j^ 8F)fluoro-3-hYdrOx^^pan-2 acid
Figure imgf000247_0001
[18F]Fluoride (3400 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg di-fert-butyl (4S) N-(tert-butoxycarbonyl)-4-{4-[(1 -hydroxy- 3-{[(4-methylphenyl)sulfonyl]oxy}propan-2-yl)oxy]benzyl}-L-glutamate in 1 mL DMSO were added to the dried residue. The resulting mixture was stirred at 120 °C for 15 min. After cooling to rt 2M HCI (1 mL) and stirred at 120 °C for 8 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 30 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water) yielding 307 MBq (23%, d.c.) 4-(4-{[1 - (18F)fluoro-3-hydroxypropan-2-yl]oxy}benzyl)-L-glutamic acid ([18F]-60) in a fraction of 1 mL buffer (fraction 3). Radiochemical purity was determined to be >99% tp = 2.7 min, analytical HPLC method C).
Example 61
carbonyl)-4-prop-2-yn-1 -yl-L-glutamate
Figure imgf000247_0002
Di-fe/f-butyl A/-(iert-butoxycarbonyl)-L-glutamate (633 mg, 1 .76 mmol) was dissolved in tetrahydrofuran (6 ml) and at -78 "C, lithium bis(trimethylsilyl)amide (1 M in tetrahydrofuran, 3.87 ml) were added dropwise. After 30 min, 3-bromo-1 -(trimethylsilyl)- 1 -propyne (370 mg, 1 .94 mmol) in tetrahydrofuran (2 ml) was added dropwise and the mixture was sturred at -78 °C for 3 h. The reaction was then warmed to 0 °C and 10 ml of 1 N hydrochloric acid were added. The mixture was extracted with dichloromethane, dried and concentrated in vacuo. The residue was purified by silica gel chromatography to give the intermediate TMS- protected alkyne. The intermediate was dissolved in 30 ml dichloromethane/methanol (1 : 1 ). Potassium carbonate (1 g) was added and the mixture was stirred for 1 h. Water (20 ml) was added and the mixture was extracted with dichloromethane, dried and concentrated in vacuo. The product (416 mg, 59%) was used in the following reaction without further purification.
MS (ESI+): m/e = 398.5 (M + H+). b) di-fert-butyl (4 ?)-W-(fert-butoxycarbonyl)- -{[1 -<2-hydroxyethyl)-1 H-1 ,2,3-triazol-
Figure imgf000248_0001
Di-fert-butyl (4S)-/V-(tert-butoxycarbonyl)-4-prop-2-yn-1 -yl-L-glutamate (150 mg, 377 μηιοΙ) and 2-azidoethanol (49 mg, 566 μιτιοΙ) were dissolved in tetrahydrofuran (3.75 ml). To the solution, copper(l) iodide (7.2 mg, 38 μιτιοΙ) and Λ/,/V-diisopropylethylamin (79 μΙ, 453 μιτιοΙ) were added and the mixture was stirred for 12 h at room temperature. The mixture was then concentrated in vacuo and the residue was purified by preparative reversed phase HPLC to yield 62 mg (34%) of the product.
MS (ESI*): m/e = 485.2 (M + H* ). c) di-fert-butyl (4R)-W-(ierf-butoxycarbonyi)-4-{[1 -(2-fluoroethyl)-1 H-1 ,2,3-triazol-4- yl]methyl}-L-glutamate
Figure imgf000249_0001
Di-tert-butyl (4R)- V-(terf-buioxycarbonyl)-4-{[1 -(2-hydroxyethyl)-1 H-1 ,2,3-triazol-4- yl]methyl}-L-glutamate (74 mg, 152.7 μιτιοΙ) was dissolved in tetrahydrofuran (5 ml) and triethyl amine (319 μΙ, 2.3 mmol), Nonafluorobutanesulfonyl fluoride (185 mg, 61 1 μιτιοΙ), and Triethylamine trihydrofluoride (98 mg, 61 1 mmol) were added subsequently. The mixture was stirred at room temperature for 6 days. The mixture was then concentrated in vacuo, and the residue was purified by silica gel chromatography to yield 30 mg (40%) of slightly impure product, which was used in the following step. MS (ESI' ): m/e = 487.2 (M + H+). l)-1 H-1 ,2,3-triazol-4-yl]methyl}-L-glutamic acid
Figure imgf000249_0002
Di-fert-butyl (4R)-/V-(terf-butoxycarbonyl)-4-{[1 -(2-fluoroethyl)-1 H-1 ,2,3-triazol-4- yl]methyl}-L-glutamate (30 mg, 61 .7 μιτιοΙ) were stirred in trifiuoroacetic acid (2 ml) for 12 h. To the reaction mixture was added dichloromethane (20 ml) and the mixture was concentrated in vacuo. The residue was purified by preparative reversed phase HPLC to yield 2 mg (1 1 %) of the product. MS (ESI ): m/e = 273.5 (M - H+).
1H-NMR (300MHz, DEUTERIUM OXIDE): δ [ppm]= 1 .98 - 2.22 (m, 2H), 3.04 - 3.1 1 (m, 3H), 3.89 - 3.97 (m, 1 H), 4.63 - 4.73 (m, 2H), 4.79 - 4.96 (m, 2H) (overlaps with solvent signal), 7.86 - 7.92 (m, 1 H). Example 62
di-terf-butyl (4/?)-N-(tert-butoxYcarbonYl)-4-r(1 -{2-r(methYlsulfonYl)oxYlethYl}-1 H-
Figure imgf000250_0001
Di-fert-butyl (4S)-W-(tert-butoxycarbonyl)-4-prop-2-yn-1 -yl-L-glutamate (60 mg, 151 μιτιοΙ) and 2-azidoethyl methanesulfonate (37.4 mg, 226 μιτιοΙ) were dissolved in tetrahydrofuran (4 ml). To the solution, copper(i) iodide (2.9 mg, 15 μιτιοΙ) and N,N- diisopropylethylamin (32 μΙ, 181 μmol) were added and the mixture was stirred for 18 h at room temperature. The mixture was then concentrated in vacuo and the residue was purified by preparative reversed phase HPLC. The product fractions were collected, lyophilized, and purified again by silicagel chromatography to yield 50 mg (47%) of the product.
MS (ESI ' ): m/e = 563.2 (M + H* ).
Ή-NMR (400MHz, DMSO-d6): δ [ppm]= 1 .34 (s, 9H), 1 .38 (s, 18H), 1 .70 - 1 .90 (m, 2H), 2.62 - 2.86 (m, 2H), 3.09 (s, 3H), 3.34 (br. s., 2H), 4.58 (m, 2H), 4.68 (m, 2H), 7.04 - 7.16 (m, 1 H), 7.85 (s, 1 H). Example 63
4-({1 -f2-(18F)f luoroethYll-1 H-1 ,2,3-triazo -yl}methyl)-L-qlUtamic acid
Figure imgf000250_0002
[18F]Fluoride (2188 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 mL). 5 mg di-fert-butyl (4R)-N-(tert-butoxycarbonyl)-4-[(1-{2- [(methylsulfonyl)oxy]ethyl}-1 H-1 ,2,3-triazol-4-yl)methyl]-L-glutamate in 1 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 120 °C for 10 min. After cooling to rt 2M HCI (1 mL) and stirred at 120 °C for 10 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 30 mL water (pH 2) and 30 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water) yielding 278 MBq (20%, d.c.) 4-({1-[2- (18F)fluoroethyl]-1 H-1 ,2,3-triazol-4-yl}methyl)-L-glutamic acid ([ 8F]-62) in a fraction of 2 mL buffer (fraction 2+3). Radiochemical purity was determined to be >98% (tR = 3.8 min, analytical HPLC method F).
Example 64
18Flfluoroethoxv)benzyllhexanedioic acid - Isomer C5-1
Figure imgf000251_0001
[ 8F]-12
Isomer C5-1
a) 1 -bromo-2-(18F)f luoroethane
[18F]Fluoride (5492 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (1 x 1 mL). 10 mg 2-bromoethyl 4-nitrobenzenesulfonate in 0.5 mL 1 ,2- dichloro benzene were added to the dried residue. 1-bromo-2-(18F)fluoroethane was distilled of the reaction mixture into a second vial filled wit 500 pL DMSO.
b) (2S)-2-amino-5-f4-(r18Flfluoroethoxv)benzyllhexanedioic acid - Isomer C5-1
A solution of 124 MBq 1 -bromo-2-( 8F)fluoroethane in 250 pL DMSO was added to a mixture of 2.1 mg (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid (isomer 1 ), 100 pL water, 10 pL 10% NaOH solution and 400 pL DMSO. The resulting mixture was stirred at 120 °C for 15 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, Waters). The cartridge was washed with 20 mL water (pH 2) and the activity was eluted with 5 mL ethanol. The ethanol fraction was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPGv2H20; 6 g NaCI in 1 L water) yielding 19 MBq (21 %, d.c.) 4-({1 -[2-(18F)fluoroethyl]-1 H-1 ,2,3-triazol-4-yl}methyl)-L-glutamic acid ([18F]- 12 Isomer C1 ) in a fraction of 1 mL buffer (fraction 2). Radiochemical purity was determined to be >98% (tR = 2.5 min, analytical HPLC method I, tR = 19.1 , analytical HPLC method G).
Example 65
Figure imgf000252_0001
[18F]-12
Isomer C5-2
A solution of 165 MBq 1 -bromo-2-(18F)fluoroethane in 250 pL DMSO was added to a mixture of 2.1 mg (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid (isomer 2), 100 pL water, 10 pL 10% NaOH solution and 400 pL DMSO. The resulting mixture was stirred at 120 °C for 15 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned C18 cartridge (C18 plus, Waters). The cartridge was washed with 20 mL water (pH 2) and the activity was eluted with 5 mL ethanol. The ethanol fraction was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPGv2H20; 6 g NaCI in 1 L water) yielding 28 MBq (21 %, d.c.) 4-({1 -[2-("8F)fluoroethyl]-1 H-1 ,2,3-triazol-4-yl}methyl)-L-glutamic acid ([18F]- 12 Isomer C2) in a fraction of 2 mL buffer (fraction 2+3). Radiochemical purity was determined to be >98% (tR = 2.5 min, analytical HPLC method I, tR = 20.1 , analytical HPLC method G). Example 66
di-tert-bu i4SH-r4j[^momethvn^
Figure imgf000253_0001
Di-ferf-butyl /V-(fert-butoxycarbonyl)-L-glutamate (1 .0 g, 2.8 mmol) was dissolved in tetrahydrofuran (16 ml) and at -78 °C, lithium bis(trimethylsilyl)amide (1 M in tetrahydrofuran, 6.12 ml) were added dropwise. After 90 min, 1 ,4- bis(bromomethyl)benzene (1 .3 mg, 3.7 mmol) was added and the mixture was stirred at -78 °C for 2.5 h. The reaction was then warmed to 0 °C and 14 ml of 2 N hydrochloric acid were added. The mixture was extracted with dichloromethane, dried and concentrated in vacuo. The residue was purified by silica gel (hexane/ethyl acetate) for afford 0.17 g (1 1 %) di-fert-butyl (4S)-4-[4-(bromomethyl)benzyl]-N-(tert-butoxycarbonyl - L-glutamate. 1H-NMR (400MHz, CHLOROFORM-d): δ [ppm]= 1 .30 (s, 9H), 1 .40 - 1.50 (m, 18H), 1.89 (t, 2H), 2.65 (quin, 1 H), 2.75 - 2.94 (m, 2H), 4.07 - 4.25 (m, 1 H), 4.47 (s, 2H), 4.88 (d, 1 H), 7.15 (d, 2H), 7.29 (d, 2H).
Example 67
Figure imgf000253_0002
[18F]-66
[18F]Fluoride (3000 MBq) was trapped on a preconditioned QMA cartridge (Sep Pak Light. Accel I Plus QMA, Waters). The activity was eluted with potassium carbonate / kryptofix solution (in acetonitrile/water) into the reaction vial. The mixture was dried under gentle nitrogen stream at 120 °C. Drying was repeated after addition of acetonitrile (2 x 1 ml_). 5 mg di-tert-butyl (4S)-4-[4-(bromomethyl)benzyl]-N-(tert- butoxycarbonyl)-L-glutamate in 0.5 mL acetonitrile were added to the dried residue. The resulting mixture was stirred at 100 "C for 8 min.
150 μΙ_ of protected crude product mixture were added to 350 μΙ_ acetonitrile and 500 μΙ_ trifluoro acetic acid and the mixture was stirred at 50 °C for 10 min. The crude product was diluted with 30 mL water (pH 2) and passed through a preconditioned Strata-X-C cartridge (200 mg, Phenomenex). The cartridge was washed with 20 mL water (pH 2) and 20 mL ethanol. The cartridge was eluted in 1 mL fractions with phosphate buffer (7 g Na2HPCv2H20; 6 g NaCI in 1 L water) yielding 31 MBq 4-{4- [(18F)fluoromethyl]benzyl}-L-glutamic acid ([18F]-66) in a fraction of 1 mL buffer (fraction 3). Radiochemical purity was determined to be >99% (tpt = 2.9 min, analytical HPLC method C).
BIOLOGY EXAMPLES
Example 68
in vitro eel I -uptake study - blocking of radiolabeled glutamate derivative uptake using compounds from the present invention
The ability of compounds from the present invention to compete with radiolabeled glutamate derivatives for uptake into tumor cells was examined. NCI-H460 (human NSCLC) cells, grown adherently in 48 well plates were used for these competition- experiments. Approximately 100.000 cells were co-incubated in PBS-buffer containing 0.1 % BSA with a radiolabeled Glutamic acid derivative and several compounds, which were used at a concentration of 1 mM for 30 minutes. After this time, the cell bound radioactivity was determined. Interestingly, it was observed, that compounds from the invention are better competitors of radiolabeled glutamic acid derivative uptake into H460 cells than the naturally occurring L-glutamic acid.
Table 1
Uptake of radiolabeled
Compound
Compound glutamate-
No
derivative
(% of control)*
L-glutamic acid - 26.1 +/- 0.3 L-cystine - 10.7 +/- 0.7
(4S)-4-[4-(2-Fluoroethoxy)benzylj-L-glutamic acid 1 5.0 +/- 0.2
(4S)-4-[4-(3-Fluoropropoxy)benzyl]-L-glutamic acid 4 3.0 +/- 0.1
4-[4-(3-Fluoropropyl)benzyl]-L-glutamic acid 9 14.2 +/- 1 .0
(2S)-2-Amino-5-[4-(2-Fluoroethoxy)benzyl]-
12 3.9 +/- 0.3 hexanedioic acid
(4S)-4-{3-[4-(2-Fluoroethoxy)
25 20.1 +/- 0.4 phenyl]propyl}-L-glutamic acid
4-{3-[4-(3-Fluoropropyl)phenyl]propyl}-L-glutamic
19 6.6 +/- 1 .6 acid
(4f?)-4-[4-(2-Fluoroeihoxy)benzyl]-D-glutamic acid 23 43.8 +/- 3.2
(4R)-4-[4-(3-Fluoropropoxy)benzyl]-D-glutamic acid 24 36.5 +/- 3.8
* Uptake of radiolabeled glutamate-derivative in H460 cells in the presence and absence of compounds from the invention (used at a concentration of 1 mM). Values are reported as % of control (mean +/- SD). Uptake of radiolabeled glutamate-derivative without addition of compound is 100 %.
Example 69
Figure imgf000255_0001
For determination of the biological activity, the F18 labeled derivatives were used as tracers in cell uptake experiments. NCI-H460 (human NSCLC) cells, grown adherently in 48 well plates were used for these uptake-experiments. Approximately 100.000 cells were incubated with 0.25 MBq of the tracers for 30 min in PBS-buffer containing 0.1 % BSA. After this time, the cell-bound radioactivity was determined using a γ-counter. Interestingly, between 3 and 15 % of the applied dose were taken up by the cells during this 30 min incubation period.
Table 2
30 min uptake
Compound
Compound into H460 cells
No
[% 100.000 cells] 4-[4-(2-[ 8F]Fluoroethoxy)benzyl]-L-glutamic acid [18F]-1 9.1 +/- 0.6
4-[4-(3-[18F]Fluoropropoxy)benzyl]-L-glutamic acid [18F]-4 10.0 +/- 0.3
4-[4-(3-p8F]fluoropropyl)benzyl]-L-glutamic acid [18F]-9 4.3 +/- 0.2
(2S)-2-amino-5-[4-(2-[18F]fluoroethoxy)benzyl]-
[ 8F]-12 10.5 +/- 0.3 hexanedioic acid
4-{4-[(3-[18F]fluoropropy!)amino]benzyl}-L-gluiamic
[18F]-8 15.3 +/- 0.1 acid
(4S)-4-{3-[4-(2-[ 8FjFluoroeihoxy) phenyl]propyl}-L-
[18F]-25 3.1 +/- 0.1 glutamic acid
4-{4-[(cis-3-[18F]Fluorocyclobutyl) oxy]benzyl}-L-
[18F]-22 4.2 +/- 0.1 glutamic acid
Example 70
Retention of 4-[4-(2-[18F]fluoroethoxy)benzyl]-L-glutamic acid ([ 8F]-1 ) in H460 cells over time
The retention of radioactivity in tumor cells was examined. Therefore, H460 cells were loaded with 0.25 MBq of the respective tracer for 30 minutes in PBS buffer, containing 0.1 % BSA. After this uptake, the buffer was removed and the cells were washed with PBS. The cells were then reincubated with new PBS buffer, without radioactivity for up to 30 minutes. The release of activity into the supernatant as well as the retention of activity inside the cells was examined. As an example, results of [18F]-1 are shown in Figure 1. It was discovered, that only a limited amount of activity was released into the supernatant during the 30 minute efflux period. More than 80% of the activity were retained inside the tumor cells during the 30 minute incubation under these efflux conditions. Similar results were obtained by using [18F]-4, [18F]-9, [18F]-12, [18F]-8 and
[18F]-22. Example 71
Competition profile indicajincujglake via xCTjSLCJAI Il
For determination of the responsible uptake mechanism, NCI-H460 tumor cells were co- incubated with the F-18 labeled tracer and several cold derivatives. These derivatives were used at a concentration of 1 mM, which is a large excess compared to the tracer. L-Glutamic acid, L-cystine, Carboxyphenylglycine (CPG) were used as competitors. In addition, also D-Glutamic acid, as well as L-aspartic acid and D-aspartic acid were used in this competition experiments. Figure 2 shows one example which was obtained by using [18F]-12. Interestingly, it was discovered, that the uptake of [18F]-12 could be reduced by more than 90% by using an excess of L-Glutamic acid, L-cystine, Carboxyphenylglycine (CPG) and the corresponding F19- compound 12. D-Glutamic acid and L-aspartic and D-aspartic acid are less effective competitors. The strong competition of L-cystine and carboxy-phenylglycine (CPG), which is described to be a specific inhibitor for xCT (SLC7A1 1 , Neuropharmacology 46 (2004) 273-284) clearly indicates specific uptake of [18F]-12 via the sodium-independent glutamate/cystine exchanger xCT. Only minor competition was observed with either D- and L-aspartic acid which are both substrates for the Na'-dependent excitatory amino acid transporter family, e.g., EAAT 1 -5. Both derivatives are not as effective as cystine and CPG are in reducing the tracer uptake, indicating only potential minor involvement of other glutamate-transporters beside the xCT. The same experiments were performed using fFJ-IJ^FH, [18F]-9, ["FJ-e^ [18F]-25 and [18F]-22. For all tested derivatives, the identical competition profile was obtained, indicating that uptake of all examined derivatives takes place mainly via the xCT. Example 72
in vivo biodistribution data
To test the pharmacokinetic properties of compounds from the present invention, all F18-labeled compounds were examined by biodistribution studies in NCI-H460 tumor bearing mice. Female NMRI (nu/nu) mice were inoculated with 5x106 NCI-H460 tumor cells 8 to 10 days before the biodistribution studies. 185 kBq of activity of the fluorinated compound was injected and at least n=3 mice were used for every time point. After injection of the F18-labeled compound, mice were sacrificed at defined time-points. All organs were removed and radioactivity was determined using a -/-counter. a) biodistribution data ofCaF]-1 are summarized in Table 3. Table 3
Figure imgf000258_0001
A high uptake into the tumor (5.88 % ID/g +/- 1 .55 at 1 hp.i.) as well as a strong retention of activity (4.06 % ID/g +/- 0.88 at 2h p.i. and 2.62 % ID/g +/- 0.19 at 4h p.i.) was observed. Clearance of the compound takes place mainly via the kidneys, with 80.2 % of activity being excreted at 1 h p.i.. High tumor to blood (ratio 32.5) and tumor to muscle (ratio 72.5) ratios were observed, indicating excellent PET imaging properties of [18F]-1. In addition, after high initial uptake into the pancreas (9.31 % ID/g +/- 2.47 at 0.25h p.i.) a very fast clearance from this organ was observed (1 h p.i. 2.68 % ID/g +/- 0.59). Therefore already at 1 h p.i., the tumor-to-pancreas ratio was found to be 2.3 (see Table 3). b) biodistribution data of[18F]-12 are summarized in
Table 4
Table 4
Figure imgf000259_0001
A high uptake into the tumor (6.47 % ID/g +/- 1 .02 at 1 h p.i.) as well as a strong retention of activity (7.21 % ID/g +/- 1 .56 at 2h p.i. and 5.17 % ID/g +/- 2.89 at 4h p.i.) was observed. Clearance of the compound takes place mainly via the kidneys, with 82.1 % of activity being excreted into the urine at 1 h p.i.. High tumor to blood (ratio 33.9) and tumor to muscle (ratio 103.4) ratios were observed, indicating excellent PET imaging properties of [18F]-12. In addition, after high initial uptake into the pancreas (1 1 .45 % ID/g +/- 1 .65 at 0.25h p.i.) a very fast clearance from this organ was observed (1 h p.i. 3.62 % ID/g +/- 0.62). Therefore already at 1 h p.i., the tumor-to-pancreas ratio was found to be 1 .8 (see Table 4).
Example 73
in vivo tumor retention
To compare the tumor uptake and retention of radioactivity of different 8F-labeled derivatives from the present invention, biodistribution studies were performed in NCI- H460 tumor bearing N RI (nu/nu) mice as described above. The tumor uptake in % injected dose per gram of tissue (%ID/g) is shown in Figure 3. Surprisingly, all examined compounds show good (more than 3 % ID/g) or excellent uptake (more than 6 % ID/g) into the H460-tumors. Additionally, strong retention of activity over time was observed with all derivatives examined.
Example 74
in vivo kidney clearance
To compare the kidney clearance of several 18F-labeled derivatives from the present invention, biodistribution studies were performed in NCI-H460 tumor bearing female NMRI (nu/nu) mice as described above. The uptake of activity in the kidneys in % I D/g is shown in Figure 4. Surprisingly, all examined compounds show very fast decrease of kidney activity. After 2h p.i., less than 1 % ID/g can be found in the kidneys. Example 75
in vivo pancreas clearance
For comparison of pancreas uptake and clearance of several 18F-labeled derivatives from the present invention, biodistribution studies were performed in NCI-H460 tumor bearing NMRI (nu/nu) mice as described above. The uptake of activity in the pancreas in %ID/g is shown in Figure 5. All examined compounds initially show uptake of about 10% ID/g at 0.25h p.i. into the pancreas, which was surprisingly followed by a fast washout. After 2h p.i., less than 2 % ID/g can be found in the pancreas.
Example 76
PET imaging studies
a) [18F]-1 was examined in NCI-H460 tumor bearing nude-mice using PET-imaging. Approx. 10 Bq of the tracer was injected into the animals and PET images were acquired at 60 min p.i. for 10 minutes. The H460-tumor was very well visible in the images with 3.6 %ID/g as was determined by region of interest (ROI) analysis. Except of some uptake into the bladder due to the renal excretion, no uptake into non target tissues was observed. b) [18F]-12 was examined in the same animal model in mice as described above. Approx. 10 MBq was injected into the animals and PET images were obtained at 60 min p.i. for 10 min. The NCI-H460 tumor was very well visible and uptake of 2.7 %ID/g into the tumor was calculated by ROI analysis. Except of some uptake into the gallbladder due to a partial hepatobiliary clearance of this derivative, the majority of activity is excreted renally, resulting in a strong PET signal from the bladder. No uptake in other non-target tissues was observed. c) Beside PET-imaging studies in mice, also the imaging properties of [18F]-12 in rats were examined. NCI-H460 tumor cells were inoculated into the right flank of nude-rats (RH-Foxn1 nu/nu) 8 to 10 days before the PET study. PET images were acquired at 60 min after injection of approximately 10 MBq for 10 minutes. The H460 tumor was nicely visible (0.9 % ID/g as determined by ROI analysis). Beside some minor uptake into the liver and kidneys due to the excretion of the compound, no uptake into other non-target tissues was observed.
Example 77
in vivo biodistribution data
To test the pharmacokinetic properties of compounds from the present invention, all F18-labeled compounds were examined by biodistribution studies in NCI-H460 tumor bearing mice. Female NMRI (nu/nu) mice were inoculated with 5x106 NCI-H460 tumor cells 8 to 10 days before the biodistribution studies. 185 kBq of activity of the fluorinated compound was injected and at least n=3 mice were used and sacrificed at defined time- points raning from 15 min p.i. up to 2h p.L All organs were removed and radioactivity was determined using a γ-counter. Data from 1 h post injection are shown in Table 5. Interestingly, all examined compounds were taken up in the tumor. High tumor uptake values of > 3 % I D/g were obtained with various compounds from the present invention. A favorable clearance profile with high tumor-to-blood and tumor-to-muscle values was observed for all compounds with makes them usefull for tumor detection in PET imaging studies.
Table 5
Figure imgf000262_0001
± 1.4 ± 0.08 ± 0.4 ± 7.8
8,2 7,5 2,6 3,5 66,8
[18F]-52 32,5 95,4
± 2,1 ± 1 ,1 ± 0,4 ± 1 ,1 ± 10,3
1.0 0.2 0.7 5.2 77
[18F]-56 9,9 25
± 0.1 ± 0.03 ± 0.2 ± 1.1 ± 6.7
Example 78
PET imaging studies
To test the imaging properties, compounds from the present invention were evaluated in PET imaging studies using tumor bearing rats. NCI-H460 tumor cells were inoculated into the right flank of nude-rats (RH-Foxn1 nu/nu) 8 to 10 days before the PET study. PET images were acquired at 60 min after injection of approximately 10 MBq for 10 minutes. After the imaging study, region-of-interest (ROI) analysis was performed and activity in tumor, liver and kidney was determined. Interestingly, all examined compounds were able to visualize the tumor. High tumor uptake values of > 1 %ID/g in this rat model were obtained with various compounds from the present invention. A favorable clearance profile of all compounds enables excellent tumor detection in PET imaging studies in tumor bearing rats.
Table 6
Figure imgf000263_0001
[18F]-58 0.3 0.63 1.7 4.6
[18F]-60 1.0 2.2 0.9 2.2
[18F]-66 0.7 1.3 1.7 2.9
Example 79
in vitro eel I -uptake and retention study - blocking of [18F]-41 uptake using 41 NCI-H460 (human NSCLC) cells, grown adherently in 48 well plates were used for these experiments. Approximately 100.000 cells were incubated in PBS-buffer containing 0.1 % BSA with 0.25 MBq [18F]~41 for up to 60 minutes. A time-dependent uptake was observed during the 60 min incubation period. Approximately 13 % of applied dose was taken up by the cells during the 60 min incubation period (Figure 6). For the blocking study [ 8F]-41 was co-incubated with 1 mM 41 for 30 minutes. After this time, the cell bound radioactivity was determined. Interestingly, it was observed, that 41 is a strong competitor for [18F]-41 , indicating specific transport of the [18F]labeled derivative into the cells (Figure 7).
In addition, the retention of radioactivity in tumor cells was examined. Therefore, H460 cells were loaded with 0.25 MBq of [18F]-41 for 30 minutes in PBS buffer, containing 0.1 % BSA. After this uptake, the buffer was removed and the cells were washed with PBS. The cells were then reincubated with new PBS buffer without radioactivity for 30 min. The release of activity into the supernatant as well as the retention of activity inside the cells was determined. It was discovered, that only a limited amount of activity was released into the supernatant during the 30 minute efflux period. More than 80% of the activity were retained inside the tumor cells during the 30 minute incubation under these efflux conditions (Figure 7) indicating strong retention.
Example 80
Uptake of compound i18F1-41 in inflammatory lesions.
To test the specificity of compounds from the present invention, compound [18F]-41 was examined in an animal model of reactive lymph nodes in comparison to the clinically commonly used PET tracer FDG. Therefore, female immunocompetent NMRI mice (10 weeks old) were injected with streptozotocin (500 g/40pL PBS) in the right hind limb to induce an inflammatory reaction in the right popliteal and additional lymph nodes. PET imaging studies were performed 3 days after Streptozotocin injection. PET images were acquired dynamically for 1 h after injection of approximately 5-10 MBq. After the imaging study, region-of-interest (ROI) analysis was performed in the popliteal, inguinal and iliacal lymph nodes. At least 3 animals were examined per tracer. Figure 8 shows the quantified activity in the lymph nodes and the time-course of compound [18F]-41 in comparison to FDG. Interestingly it was observed, that the initial uptake of compound [18F]-41 in the inflammatory lesions was already reduced compared to FDG. Additionally, whereas the activity of FDG in the reactive lymph nodes remained almost constant during the imaging period, a wash-out of radioactivity was observed during the PET study with compound [18F]-41. In summary, these results indicate a higher specificity of compounds from the present invention due to lower uptake in inflammatory processes and wash-out from the lesions during the imaging period.
DESCRIPTION OF THE FIGURES
FIGURES
Figure 1 : Retention of 4-[4-(2-[ 8F]fluoroet oxy)benzyl]-L-glutamic acid ([18F]-1 ) in H460 cells over time
Figure 2: Competition profile indicating uptake of (2S)-2-Amino-5-[4-(2- [18F]fluoroethoxy)benzyl]hexanedioic acid([18F]-12) via xCT (SLC7A1 1 )
Figure 3: in vivo tumor retention of [18F]-1 , [18F]-4, [18F]-12 and [18F]-8 in H460 tumors Figure 4: in vivo kidney clearance of [18F]-1 , [18F]-4, [18F]-12 and [18F]-8 in female NMRI (nu/nu) mice
Figure 5: in vivo pancreas clearance of [18F]-1 , [18F]-4, [18F]-12 and [ 8F]-8 in female NMRI (nu/nu) mice
Figure 6: Time-dependent uptake of [18F]-41 in NCI-H460 cells
Figure 7: Blocking and retention of [18F]-41
Figure 8: Time-course of activity of FDG and [18F]-41 in reactive lymph nodes caused by streptozotocin injection

Claims

1 ) A co
Figure imgf000267_0001
wherein,
R1 is a carboxyi protecting group,
R2 is a carboxyi protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2, and
Figure imgf000267_0002
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*, g) (R6-0),(R7-0)-disubstituted alkylene, h) (R6-0),(R7-0)-disubstituted alkylene-O*, i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q.
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a) hydrogen or
b) hydroxyl protecting group,
R7 i is: a) hydrogen or
b) hydroxy! protecting group,
LG is a leaving group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
The compound according to claim 1 wherein independently from each other
R1 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, tert- butyl, ally!, benzyl, 4-methoxybenzyl and 4-methoxyphenyl,
R2 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, tert- butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl,
R3 is hydrogen,
R4 is iert-butyloxycarbonyl (Boc) or triphenylmethyl (Trityl),
Q is phenylene or pyridylene,
X is selected from the group comprising:
a) CH2, and
Figure imgf000268_0001
LG is selected from the group comprising:
a) sulfonate leaving group, and
b) halogen.
3) The compound according to the claims 1 or 2, selected from the list below:
]benzyl}glutamate:
xy]benzyl}glutamate:
Figure imgf000268_0002
i-iert-butyl N-(iert-butoxycarbonyl)-4-{4-[3-(tosyloxy)propyl]benzyl}glutamate:
Figure imgf000269_0001
di-fert-butyl A/-(iert-butoxycarbonyl)-4-(4-{[3-(tosyloxy)propyl]amino}benzyl)glutamate:
Figure imgf000269_0002
di-fert-butyl N-(fert-butoxycarbonyl)-4-(4-{[3-(tosyloxy)cyclobutyl]oxy}benzyl)glutamate:
Figure imgf000269_0003
di-tert-butyl N-(tert-butoxycarbonyl)-4-{4-[(1 -hydroxy-3-{[(4-methylphenyl)sulfonyl]oxy}-
Figure imgf000269_0004
di-iert-butyl /V-(iert-butoxycarbonyl)-4-(3-{4-[2-(tosyloxy)ethoxy]phenyl}propyl)glutamate:
Figure imgf000269_0005
-fert-butyl N-(fert-butoxycarbonyl)-4-(3-{4-[3-(tosyloxy)propyl]phenyl}propyl)glutamate:
Figure imgf000270_0001
di-fert-butyl 2-[(ferf-butoxycarbonyl)amino]-5-{4-[2-(tosyloxy)ethoxy]b!
Figure imgf000270_0002
di-fert-butyl \/-(fert-butoxycarbonyl)-4-({5-[3-(tosyloxy)propyl]pyridin-2-yl}methyl)- )ethoxy]benzyl}-L-glutamate:
Figure imgf000270_0003
di-fert-butyl (4S)-N-(ferf-butoxycarbonyl)-4-{4-[3-(tosyloxy)propoxy]benzyl}-L-glutamate:
Figure imgf000271_0001
di-terf-butyl (4S)-/V-(fert-butoxycarbonyl)-4-{4-[3-(tosyloxy)propyl]benzyl}-L-glutamate:
Figure imgf000271_0002
di-terf-butyl (4S)-A/-(terf-butoxycarbonyl)-4-(4-{[3-(tosyloxy)propyl]amino}benzyl)-L-
Figure imgf000271_0003
di-terf-butyl (4S)-/V-(terf-butoxycarbonyl)-4-(4-{frans-[3-(tosyloxy)cyclobutyl]oxy}bi
Figure imgf000271_0004
di-terf-butyl (4S)-/V-(terf-butoxycarbonyl)-4-(3-{4-[2-(tosyloxy)ethoxy]phenyl}propyl)-L- glutamate:
Figure imgf000272_0001
Figure imgf000272_0002
di-iert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-{4-[2-(tosyloxy)ethoxy]b!
Figure imgf000272_0003
di-fert-butyl (2R)-2-[(tert-buioxycarbonyl)amino]-5-{4-[2-(tosyloxy)ethoxy]benzyl}-
Figure imgf000272_0004
di-ferf-butyl (4R)-W-(terf-butoxycarbonyl)-4-({5-[3-(tosyloxy)propyl]pyridin-2-yl}methyl)-L-
Figure imgf000273_0001
4) A compound of For
Figure imgf000273_0002
wherein
X is selected from the group comprising
a) CH2, and
Figure imgf000273_0003
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alky!ene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof. 5) The compound according to claim 4 wherein Q is phenylene or pyridylene.
6) The compound according to the claims 4 or 5 selected from the group below:
18F]fluoroethoxy)benzyl]glutamic acid:
Figure imgf000274_0001
18F]fluorocyclobutyl)oxy]benzyl}glutamic acid:
Figure imgf000274_0002
4-{3-[4-(2-[ 8F]fluoroethoxy)phenyl]propyl}glutamic acid:
Figure imgf000275_0001
8F]fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000275_0002
18F]fluoroethoxy)benzyl]-L-glutamic acid:
Figure imgf000275_0003
18F]fluoropropoxy)benzyl]-L-glutamic acid:
Figure imgf000275_0004
18F]fluoropropyl)benzyl]-L-glutamic acid:
Figure imgf000275_0005
18F]fluoropropyl)amino]benzyl}-L-glutamic acid:
Figure imgf000275_0006
4-{4-[(cis-3-[18F]fluorocyclobutyl)oxy]benzyi}-L-glutamic acid:
Figure imgf000276_0001
18F]fluoroeihoxy)phenyl]propyl}-L-glutamic acid:
Figure imgf000276_0002
-[4-(2-[18F]fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000276_0003
-[4-(2-[ 8Fjfluoroet oxy)benzyl]hexanedioic acid:
Figure imgf000276_0004
(4-{[5-(2-[18F]fluoroethoxy)pyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000276_0005
-{[5-(2-[ 8F]fluoroet oxy)pyridin-2-yl]methyl}hexanedioic acid:
Figure imgf000276_0006
4-{[5-(2-[18F]fluoroethoxy)-1-oxidopyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000277_0001
(2S)-2-amino-5-{2-[4-(2-[ 8F]fluoroethoxy)phenyl]ethyl}hexanedioic acid:
Figure imgf000277_0002
18F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000277_0003
Another more preferred compound of Formula III is (2S,5R)-2-amino-5-[4- 18F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000277_0004
Another more preferred compound of Formula III is (2S.5S)-2-amino-5-[4- 8F]fluoromethoxy)benzyl]hexanedioic acid:
Figure imgf000277_0005
4-[4-(2-[18F]fluoroethoxy)-3-hydroxybenzyl]-L-glutamic acid:
Figure imgf000278_0001
(4S)-4-{4-[(18F)fluoromet oxy]benzyl}-L-glutamic acid:
Figure imgf000278_0002
(4R)-4-{4-[(18F)fiuoromethoxy]benzyl}-L-glutamic
Figure imgf000278_0003
18F)fluoroethyl]amino}benzyl)hexanedioic acid:
Figure imgf000278_0004
(2S)-2-amino-5-(4-{[(2S,3f?)-4-( 8F)fluoro-2,3-dihydroxybutyl]oxy}benzyl)hexanedioic acid:
Figure imgf000278_0005
4-({6-[2-(18F)fluoroethoxy]pyridin-3-yl}methyl)-L-glutamic acid:
Figure imgf000279_0001
Figure imgf000279_0002
Figure imgf000279_0003
-C8F)fluoroet yl]-1 H-1 ,2,3-triazoi-4-yl}met yl)-L-glutamic acid:
Figure imgf000279_0004
, 18F]fluoroet oxy)benzyl]hexanedioic acid:
Figure imgf000279_0005
(2S,5S)-2-amino-5-[4-([18F]fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000280_0001
Figure imgf000280_0002
7) A compound of Fo
Figure imgf000280_0003
wherein,
R1 is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group, wherein at least one of R1, R2, R3 and R* is not hydrogen, X is selected from the group comprising:
a) CH2, and
Figure imgf000280_0004
A is alkylene,
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*.
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*, g) ( 6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy! protecting group,
R6 is
a) hydrogen or
b) hydroxy! protecting group,
R7 is
a) hydrogen or
b) hydroxy! protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
8) The compound according to claim 7 wherein independently from each other
R1 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, tert- butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl,
R2 is a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, tert- butyl, allyl, benzyl, 4-methoxybenzyl and 4-methoxyphenyl,
R3 is hydrogen,
R4 is fert-butyloxycarbonyl (Boc) or triphenylmethyl (Trityl),
Q is phenylene or pyridylene, and
X is selected from the group comprising:
a) CH2, and
Figure imgf000281_0001
9) The compound according to the claims 7 or 8 selected from the group below:
2-[18F]fluoroethoxy)benzyl]glutamate:
Figure imgf000281_0002
18F]fluoropropoxy)benzyl]glutamate: 8F]fluoropropyl)benzyl]glutamate: [ 8F]fluoropropyl]amino}benzyl)glutamate:
Figure imgf000282_0001
di-fert-butyl /V-(fert-butoxycarbonyl)-4-(4-{c s-[3-[ 8F]fluorocyclobutyl]-
Figure imgf000282_0002
di-fert-butyl /V-(fert-butoxycarbonyl)-4-{3-[4-(2-[ 8F]fluoroethoxy)ph
Figure imgf000282_0003
di-iert-butyl 2-[(iert-butoxycarbonyl)amino]-5-[4-(2-[18F]fluoroethoxy)benzyl]hexane-
Figure imgf000283_0001
di-ferf-butyl A -(terf-butoxycarbonyl)-4-[4-(2-[ 8F]fluoroethoxy)benzyl]-L-glutamate: -[18F]fluoropropoxy)benzyl]-L-glutamate: -[ 8F]fluoropropyl)benzyl]-L-glutamate:
Figure imgf000283_0002
di-iert-butyl A/-(iert-butoxycarbonyl)-4-(4-{[3-[18F]fluoropropyl]amino}benzyl)-L-
Figure imgf000283_0003
di-iert-butyl N-(fert-butoxycarbonyl)-4-(4-{c/s-[3-[18F]iluorocyclobuiy!]oxy}benzyl)-L-
Figure imgf000284_0001
di-fert-butyl (4S)-A/-(iert-butoxycarbonyl)-4-{3-[4-(2-[ 8F]fluoroethoxy)phenyl]propyl}-L- glutamate:
Figure imgf000284_0002
di-iert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[4-(2-[18F]fluoroethoxy)benzyl]hexane-
Figure imgf000284_0003
, and
di-fert-butyl (2R)-2-[(fert-butoxycarbonyl)amino]-5-[4-(2-[18F]fluoroethoxy)benzyl]- hexanedioate:
Figure imgf000284_0004
di-tert-butyl N-(fert-butoxycarbonyl)-4-({5-[2-( 8F)fluoroethoxy]pyridin-2-yl}methyl)-L- glutamate:
Figure imgf000285_0001
di-iert-butyl (2S)-2-[(iert-butoxycarbonyl)amino]-5-{[5-(2-[18F]fluoroethoxy)pyridin-2-
Figure imgf000285_0002
di-iert-Butyl N-(tert-butoxycarbonyl)-4-{[5-(2-[18F]fluoroethoxy)-1 -oxidopyridin-2- yl]met yl}-L-glutamate:
Figure imgf000285_0003
(2S)-2-fert-butoxycarbonylamino-5-{2-[4-(2-[18Fjfluoro-ethoxy)-phenyl]-ethyl}- r:
Figure imgf000285_0004
is di-iert-butyl-N-(fert-butoxycarbonyl)-4-[3-iert-butoxy-4-(2-[18F]fluoroethoxy)benzyl]-L-
Figure imgf000286_0001
di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-(4-{(tert-butoxycarbonyl)[2-
(18F)fluoroet yl]amino}benzyl)hexanedioate:
Figure imgf000286_0002
di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[4-({(4S,5R)-5-[('8F)fluoromethyl]-2,2- yl] exanedioate:
Figure imgf000286_0003
di-fert-butyl (4S)-N-(fert-butoxycarbonyl)-4-({6-[2-( 8F)fluoroethoxy]pyridin-3-yl}methyl)- L-glutamate:
Figure imgf000287_0001
di-fert-butyl (4S)-N-(terf-butoxycarbonyl)-4-[4-({(4S,5R)-5-[(18F)fluoromethyl]-2,2- dimet yl-1 ,3-dioxolan-4-yl}methoxy)benzyl]-L-glutamate:
Figure imgf000287_0002
di-fert-butyl (4S)-N-(ferf-butoxycarbonyl)-4-(4-{[1 -(18F)fluoro-3-hydroxypropan-2- yl]oxy}benzyl)-L-glutamate:
Figure imgf000287_0003
di-fert-butyl (4R)-N-(ferf-butoxycarbonyl)-4-({1 -[2-( 8F)fluoroethyl]-1 H-1 ,2,3-triazol-4- yl}methyl)-L-glutamate:
Figure imgf000287_0004
di-fert-butyl N-(fert-butoxycarbonyl)-4-{4-[(18F)fluoromethyl]benzyl}-L-glutamate:
Figure imgf000288_0001
10) A compound of F
Figure imgf000288_0002
VI
wherein,
X is selected from the group comprising
a) CH2, and
Figure imgf000288_0003
A is alkylene,
Q is arylene or heteroarylene,
L1 is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*.
e) monohydroxyalkylene,
f) monohydroxyalkylene-O*,
g) dihydroxyalkylene,
h) dihydroxyalkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
1 1 ) The compound according to claim 10 wherein Q is phenylene or pyridylene. 12) The compound according to the claims 10 or 1 1 selected from the group below: -[4-(2-fluoroethoxy)benzyl]glutamic acid:
Figure imgf000289_0001
4-(3-{4-[2-fluoroethoxy]phenyl}propyl)glutamic acid:
glutamic acid:
Figure imgf000290_0001
2-amino-5-{4-[2-fluoroethoxy]benzyl} exanedioic acid:
Figure imgf000290_0002
(4R)-4-[4-(2-fluoroet oxy)benzyl]-D-glutamic acid:
Figure imgf000290_0003
-4-[4-(3-fluoropropoxy)benzyl]-L-glutamic acid:
Figure imgf000291_0001
id:
Figure imgf000291_0002
ropyi)-L-glutamic acid:
Figure imgf000291_0003
ropyl)-L-glutamic acid:
Figure imgf000292_0001
enzyl] exanedioic acid: nzyl]hexanedioic acid:
Figure imgf000292_0002
(4R)-4-{[5-(3-Fluoropropyl)pyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000292_0003
(4f?)-(4-{[5-(2-fluoroet oxy)pyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000292_0004
-5-{[5-(2-fluoroet oxy)pyridin-2-yi]methyl}hexanedioic acid:
Figure imgf000292_0005
(4R)-4-{[5-(2-fluoroethoxy)-1-oxidopyridin-2-yl]methyl}-L-glutamic acid:
Figure imgf000293_0001
-5-{2-[4-(2-fluoroethoxy)phenyl]ethyl}hexanedioic acid:
Figure imgf000293_0002
-2-amino-5-[4-(fluoromethoxy)benzyl] exanedioic acid:
Figure imgf000293_0003
oxy)benzyl]hexanedioic acid:
Figure imgf000293_0004
-amino-5-[4-(fluoromethoxy)benzyi]hexanedioic acid:
Figure imgf000293_0005
(4S)-4-[4-(2-fluoroethoxy)-3- ydroxybenzyl]-L-glutamic acid:
Figure imgf000294_0001
(4S)-4-{4-[(fluoromethoxy]benzyl}-L-glutamic acid:
Figure imgf000294_0002
(4R)-4-{4-[fluoromethoxy]benzyl}-L-glutamic acid:
Figure imgf000294_0003
ino}benzyl)hexanedioic acid:
Figure imgf000294_0004
(2S)-2-amino-5-(4-{[(2S,3R)-4-fluoro-2,3-dihydroxybutyl]oxy}benzyl)hexanedioic acid:
Figure imgf000294_0005
(4S)-4-({6-[2-fluoroethoxy]pyridin-3-yl}methyl)-L-gluiamic acid:
Figure imgf000295_0001
4S)-4-(4-{[(2S,3R)-4-fluoro-2,3-dihydroxybuiyl3oxy}benzyl)-L-glutamic acid:
Figure imgf000295_0002
4S)-4-(4-{[1-fluoro-3- ydroxypropan-2-yl]oxy}benzyl)-L-glutamic acid:
Figure imgf000295_0003
-({1-[2-fluoroet yl]-1 H-1.2.3-triazol-4-yl}methyl)-L-glutamic acid:
Figure imgf000295_0004
benzyi] exanedioic acid:
Figure imgf000295_0005
2S.5S)-2-amino-5-[4-(fluoroethoxy)benzyl]hexanedioic acid:
Figure imgf000296_0001
(4S)-4-{4-fluoromethyljbenzyl}-L-glutamic acid:
Figure imgf000296_0002
13) A compound of F
Figure imgf000296_0003
wherein,
R is hydrogen or a carboxyl protecting group,
R2 is hydrogen or a carboxyl protecting group,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group, wherein at least one of R1, R2, R3 and R4 is not hydrogen, X is selected from the group comprising:
a) CH2, and
Figure imgf000296_0004
A is alkylene.
Q is arylene or heteroarylene,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-NPH,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*, g) ( 6-0),(R7-0)-disubstituted alkylene,
h) (R6-0),(R7-0)-disubstituted alkylene-O*, and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy! protecting group,
R6 is
a) hydrogen or
b) hydroxy! protecting group,
R7 is
a) hydrogen or
b) hydroxy! protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof.
14) The compound according to claim 13 wherein Q is phenylene or pyridylene.
15) The compound according to claims 13 or 14 selected from the group below:
-fluoroethoxy]benzyl}glutamate:
-fluoropropoxy]benzyl}glutamate:
Figure imgf000297_0001
di-fert-butyl W-(fert-butoxycarbonyl)-4-{4-[3-fluoropropyl]benzyl}glutamate:
Figure imgf000298_0001
[2-fluoropropyl]phenyl}propyl)glutamate:
Figure imgf000298_0002
di-fert-butyl 2-[(fert-butoxycarbonyl)amino]-5-{4-[2-fluoroethoxy]benzyl}hexanedioate:
Figure imgf000299_0001
di-fert-butyl V-(tert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}glutamate:
Figure imgf000299_0002
di-fert-butyl /V-(fert-butoxycarbonyl)-4-{[5-(3-fluoropropyl)pyridin-2-yl]methyl}-glutamate:
-[4-(2-fluoroethoxy)benzyl]-L-glutamate: -[4-(2-fluoroethoxy)benzyl]-D-glutamate:
Figure imgf000299_0003
di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-{4-[3-fluoropropoxy]benzyl}-L-glutamate: -{4-[3-fluoropropoxy]benzyl}-D-glutamate:
-fluoropropyl]benzyl}-L-glutamate:
Figure imgf000300_0001
di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-(4-{[3-fluoropropyl]amino}benzyl)-L-
Figure imgf000300_0002
di-fert-butyl (4S)- V-(fert-butoxy(4S)-carbonyl)-4-(4-{[cis-3-fluorocyclobutyl]oxy}b!
Figure imgf000300_0003
di-fert-butyl (4S)-/V-(fert-butoxycarbonyl)-4-(3-{4-[2-fluoroethoxy]phenyl}propyl)-L- glutamate:
Figure imgf000301_0001
di-iert-butyl (2S)-2-[(tert-butoxycarbonyi)amino]-5-{4-[2-
Figure imgf000301_0002
di-fert-butyl (2R)-2-[(terf-butoxycarbonyl)amino]-5-{4-[2-
Figure imgf000301_0003
di-iert-butyl (4f?)-/V-(iert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}-L- glutamate:
Figure imgf000301_0004
di-fert-butyl (4R)-/V-(fert-butoxycarbonyl)-4-{[5-(3-fluoropropyl)pyridin-2-yl]methyl}-L- glutamate:
Figure imgf000302_0001
di-tert-butyl (4R)-N-(tert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)pyridin-2-yl]methyl}-L- glutamate:
Figure imgf000302_0002
di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-{[5-(2-fluoroethoxy)pyridin-2-
Figure imgf000302_0003
di-tert-butyl (4R) N-(fert-butoxycarbonyl)-4-{[5-(2-fluoroethoxy)-1 -oxidopyridin-2- yl]methyl}-L-glutamate:
Figure imgf000302_0004
(2S)-2-iert-butoxycarbonylamino-5-{2-[4-(2-fluoro-ethoxy)-phenyl]-ethyl}-hexanedioic acid di-fert-butyl ester:
Figure imgf000303_0001
di-fert-butyl (4S)-N-(fert-butoxycarbonyl)-4-[3-fert-butoxy-4-(2-fluoroethoxy)bi
Figure imgf000303_0002
di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-(4-{(fert-butoxycarbonyl)[2-
Figure imgf000303_0003
di-fert-butyl (2S)-2-[(fert-butoxycarbonyl)amino]-5-[4-({(4S,5R)-5-[fluoromethyl]-2,2- dimethyl-1 ,3-dioxolan-4-yl}methoxy)benzyl]hexanedioate:
Figure imgf000304_0001
di-fert-butyl (4S)-N-(terf-butoxycarbonyl)-4-({6-[2-fluoroethoxy]pyridin-3-yl}methyl)-L- glutamate:
Figure imgf000304_0002
di-fert-butyl (4S)-N-(fer -butoxycarbonyl)-4-[4-({(4S,5R)-5-[fluoromethyl]-2,2-dimethyl- 1 ,3-dioxolan-4-yl}methoxy)benzyl]-L-glutamate:
Figure imgf000304_0003
di-ferf-butyl (4S)-N-(ferf-butoxycarbonyl)-4-(4-{[1 -fluoro-3-hydroxypropan-2- yl]oxy}benzyl)-L-glutamate:
Figure imgf000304_0004
is di-tert-butyl (4R)-N-(tert-butoxycarbonyl)-4-({1 -[2-fluoroethyl]-1 H-1 ,2,3-triazol-4-
onyl)-4-[4-(fluoromethyl)benzyi]-L-glutamate:
Figure imgf000305_0001
16) A compound of Fo
Figure imgf000305_0002
IV
wherein
R1 is a carboxyl protecting group or hydrogen,
R2 is a carboxyl protecting group or hydrogen,
R3 is hydrogen or an amine protecting group,
R4 is hydrogen or an amine protecting group,
X is selected from the group comprising:
a) CH2, and
b) CH2-CH2,
A is alkylene,
Q is arylene or heteroarylene,
Z is selected from the group comprising:
a) HO-L*,
b) OH, c) Halogen, and
d) NH2,
L is selected from the group comprising:
a) alkylene,
b) alkylene-O*,
c) alkylene-N*H,
d) cycloalkylene-O*,
e) (R5-0)-substituted alkylene,
f) (R5-0)-substituted alkylene-O*,
g) (R6-0),(R7-0)-disubstituted alkylene,
h) (R6-0).(R7-0)-disubstituted alkylene-O*. and
i) (CH2CH20)n-CH2CH2-0* with n = 1 , 2 or 3,
* indicates the position of the bond to Q,
R5 is
a) hydrogen or
b) hydroxy I protecting group,
R6 is
a) hydrogen or
b) hydroxy I protecting group,
R7 is
a) hydrogen or
b) hydroxy I protecting group, and
single isomers, tautomers, diastereomers, enantiomers, stereoisomers, stereoisomeric mixtures or mixtures thereof,
with the provisos, that:
Z is not Halogen if X is CH2,
Z is not OH if X is CH2, and Q is phenyl or
Z is not Halogen if X is CH2-CH2.
The compound according to claim 16 wherein independently from each other R1 is hydrogen or a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl, 4-methoxyphenyl,
R2 is hydrogen or a carboxyl-protecting group selected from methyl, ethyl, propyl, butyl, fert-butyl, allyl, benzyl, 4-methoxybenzyl, 4-methoxyphenyl,
R3 is hydrogen,
R4 is hydrogen, fert-butyloxycarbonyl (Boc), or triphenylmethyl (Trityl) Q is phenylene or pyridylene, and
X is selected from the group comprising:
a) CH2, and
Figure imgf000307_0001
with the provisos, that:
Z is not Halogen if X is CH2,
Z is not OH if X is CH2, and Q is phenyl or
Z is not Halogen if X is CH2-CH2.
18) The compound according to claims 16 or 17 selected from the list below:
hydroxybenzyl)glutamate:
toxycarbonyl)glutamate:
(3-hydroxypropyl)benzyl]glutamate:
Figure imgf000307_0002
di-fert-butyl A/-(fert-butoxycarbonyl)-4-[3-(4-hydroxyphenyl)propyl]glutamate:
Figure imgf000308_0001
Figure imgf000308_0002
Figure imgf000308_0003
di-fert-butyl (4S)-4-(4-aminobenzyl)-/V-(tert-butoxycarbonyl)-L-glutamate:
Figure imgf000308_0004
di-fert-butyl (4S)-/V-(tert-butoxycarbonyl)-4-[4-(3-hydroxypropyl)benzyl]-L-glutamate:
Figure imgf000309_0001
di-fert-butyl (4S)-/V-(iert-butoxycarbonyl)-4-[3-(4-hydroxyphenyl)propyl]-L-glutamate:
Figure imgf000309_0002
di-fert-butyl (2S)-2-[(iert-butoxycarbonyl)amino]-5-(4-hydroxybenzyl)hexanedioate:
Figure imgf000309_0003
di-fert-butyl (2R)-2-[(fert-butoxycarbonyl)amino]-5-(4-hydroxybenzyl)hexanedioate:
Figure imgf000309_0004
di-fert-butyl (4R)-/V-(iert-butoxycarbonyl)-4-[(5-hydroxypyridin-2-yl)methyl]-L-glutamate:
Figure imgf000309_0005
di-ferf-butyi (2S)-2-[(ferf-butoxycarbonyi)amino]-5-[(5-hydroxypyridin-2- yl)methyl]hexanedioate:
Figure imgf000310_0001
di-ferf-butyi (2S)-2-[(ferf-butoxycarbonyi)amino]-5-[2-(4-
Figure imgf000310_0002
(2S)-2-ferf.-Butoxycarbonyiamino-5-(4-hydroxy-benzyi)-hexanedioic acid di-ferf.-buty!
Figure imgf000310_0003
(2S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid:
Figure imgf000310_0004
(2S.5f?)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid:
Figure imgf000311_0001
(2S,5S)-2-amino-5-(4-hydroxybenzyl)hexanedioic acid:
dimethyl (2S)-2-amino-5-(4-hydroxybenzyl)hexanedioate:
Figure imgf000311_0003
di-fert-butyl (4S)-N-(iert-butoxycarbonyl)-4-[3-fert-butoxy-4-(2-hydroxyethoxy)benzyl]-L- glutamate:
tert-butoxycarbonyl)amino]hexanedioate:
Figure imgf000311_0004
19) Methods for preparation of compound of Formula III according to claim 4 to 6.
20) Methods for preparation of compound of Formula VI according to claim 10 to 12. 21 ) A compound of Formula III according to claim 4 to 6 as medicament or pharmaceutical.
22) A compound of Formula III according to claims 4 to 6 for manufacturing of an imaging tracer or radiopharmaceutical agent for imaging proliferative diseases.
23) A kit comprising one vial or more than one vial comprising a predetermined quantity of:
a) Compounds of Formula I or Formula IV. or
b) Compounds of Formula VI. 24) A composition comprising compounds of formula I, II, III, IV, V or VI according to preceding claims or mixture thereof.
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