WO2013038153A1 - 18f-labelled barbiturate compounds for use as positron emission imaging agents - Google Patents

18f-labelled barbiturate compounds for use as positron emission imaging agents Download PDF

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WO2013038153A1
WO2013038153A1 PCT/GB2012/052206 GB2012052206W WO2013038153A1 WO 2013038153 A1 WO2013038153 A1 WO 2013038153A1 GB 2012052206 W GB2012052206 W GB 2012052206W WO 2013038153 A1 WO2013038153 A1 WO 2013038153A1
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compound according
disease
disorder
groups
present
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French (fr)
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Matteo Zanda
Bettina Platt
Iain Robert Greig
Elisa CALAMAI
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The University Court Of The University Of Aberdeen
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
    • C07D239/02—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings
    • C07D239/24—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members
    • C07D239/28—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms
    • C07D239/46—Two or more oxygen, sulphur or nitrogen atoms
    • C07D239/60—Three or more oxygen or sulfur atoms
    • C07D239/62—Barbituric acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B59/00—Introduction of isotopes of elements into organic compounds ; Labelled organic compounds per se
    • C07B59/002—Heterocyclic compounds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
    • C07D239/02—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings
    • C07D239/24—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members
    • C07D239/28—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms
    • C07D239/46—Two or more oxygen, sulphur or nitrogen atoms
    • C07D239/60—Three or more oxygen or sulfur atoms
    • C07D239/66—Thiobarbituric acids

Definitions

  • the present invention relates generally to the field of diagnostic methods. More specifically, the present invention pertains to certain 18 F-labelled barbiturate compounds (collectively referred to herein as “ 18 F-fluorinated barbiturate compounds” and “ 18 FBAR compounds”) that bind to metals, for example, metals associated with protein aggregates, and as such are useful as imaging agents for positron emission imaging (e.g., positron emission tomography (PET) imaging) used in the diagnosis and monitoring of conditions involving these metals and/or aggregates, including Alzheimer's disease (AD),
  • positron emission imaging e.g., positron emission tomography (PET) imaging
  • AD Alzheimer's disease
  • Parkinson's disease PD
  • Huntington's disease HD
  • these compounds also bind strongly to GABA A receptors and hence are also useful as imaging agents for positron emission imaging (e.g., positron emission tomography (PET) imaging) used in the diagnosis, monitoring and study of diseases involving dis-regulation of these receptors, including epilepsy, schizophrenia, and mood disorders (e.g., anxiety).
  • PET positron emission tomography
  • Barbiturates have found extensive clinical use in the past as hypnotics, anxiolytics and sedatives. Safety issues, such as physical dependence, drug-drug interactions, respiratory depression and a low therapeutic index have restricted usage in recent years. However, several barbiturates remain in clinical use today, including: phenobarbital, as an anti-convulsant for the control of epilepsy; thiopental, as a fast-acting but transient anaesthetic; and pentobarbital, as a rarely-used anxiolytic or sedative.
  • One of the features common to many barbiturates is rapid passage through the blood-brain barrier, which gives a rapid pharmacological effect.
  • barbiturates are derivatives of barbituric acid (also referred to as pyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one) (shown below).
  • barbituric acid is recognized to encompass derivatives of barbituric acid and salts thereof, in which: one or both of the ring nitrogen atoms has a substituent (e.g., an alkyl group) (e.g., as in narconumal); the 2-oxo group is replaced with a 2-thio group (e.g., as in thiopental sodium); one substituent, or more often two substituents, are present at the 5-position; or a combination thereof.
  • substituent e.g., an alkyl group
  • 2-thio group e.g., as in thiopental sodium
  • barbiturates have a number of properties which make them ideal as targeting agents for use in the diagnosis and monitoring of a number of neurological disorders.
  • the primary attributes of barbiturates upon which this application is based are: the strong binding of barbiturates to metals, a number of which are found in elevated concentrations in neurodegenerative disorders, including
  • AD Alzheimer's disease
  • polar molecules such as melamine
  • hydrogen bonded recognition patterns could lead to the formation of stable aggregates with the peptides and proteins involved in neurological disorders, including beta-amyloid peptide (see, e.g., Yagai, 2006); the strong binding of barbiturates to the GABA A receptor, which is dis-regulated in a number of neurological disorders, including epilepsy, anxiety and schizophrenia.
  • Fluorine (F) exists as one of six isotopes: 17 F, 18 F, 19 F, 20 F, 21 F, and 22 F.
  • the natural abundance of 19 F is 100%.
  • the radioisotope 18 F can be prepared using conventional means (e.g., by bombarding 18 0-enriched water with high energy protons) and has a half-life of about 1 10 minutes. When 18 F decays, it generates 18 0 and positrons ( ⁇ + ).
  • PET positron emission tomography
  • PET may be used for early detection and monitoring of diseases, as well as investigating the efficacy of drugs.
  • functional information is not available from other conventional imaging techniques such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI).
  • CT Computed Tomography
  • MRI Magnetic Resonance Imaging
  • these imaging modalities provide a detailed picture of the body's internal anatomy (anatomical information).
  • CT Computed Tomography
  • these imaging modalities provide a detailed picture of the body's internal anatomy (anatomical information).
  • CT Computed Tomography
  • MRI Magnetic Resonance Imaging
  • Beta-amyloid as commonly found in AD, has strong chelating properties for Cu(ll) and Zn(ll) (see, e.g., Domingo, 2006; Adlard and Bush, 2006).
  • Copper has an exceptionally high affinity for ⁇ -amyloid and binding coefficients of
  • Zinc has a somewhat lower affinity for ⁇ -amyloid than copper, with K D values of 100 nM reported (see, e.g., Cuajungco and Faget, 2003); however zinc is an essential element and is therefore normally present at higher concentrations than copper and therefore is likely to be an equally important disease marker.
  • neurofibrillary tangles see, e.g., White and Bush, 2008
  • AD pathology see, e.g., Lei, 2012
  • Other metals shown to have elevated levels in amyloid plaques include aluminium, chromium and nickel.
  • High localised concentrations of these metals can be used for early diagnosis and effective monitoring of therapy.
  • Early stage dementia is often unrecognised or misdiagnosed; pre-symptomatic diagnosis would facilitate early intervention and thus improve the chances of successful therapy, either preventing development of full-blown disease or delaying progression to the debilitating symptomatic stages.
  • these metals may play an important role in seeding the formation of these aggregates and that their removal may be of therapeutic benefit (see, e.g., Domingo, 2006); this hypothesis is supported by the current clinical development of clioquinol, an antibiotic / anti-amoebic agent which strongly binds Cu(ll) and Zn(ll) (see, e.g., Domingo, 2006) as a treatment for AD (see, e.g., Mancino et al., 2009). Phase II studies on clioquinol showed a 49% decrease in brain ⁇ deposition (see, e.g., Domingo, 2006). Removal of these metals may have other beneficial effects, including reduction in oxidative stress caused by redox-active transition metals such as copper.
  • Dis-regulation or accumulation of metals has also been shown to play a role in other neurodegenerative disorders, including amyotrophic lateral sclerosis (see, e.g., Piatt, 2006), particularly in the case of iron, and Huntington's disease (see, e.g., Yokel, 2006; Bush and White, 2008). Elevated levels of iron have also been found in the affected region (the substantia nigra) of PD patients and this is often regarded as a disease in which occupational exposure to a number of metals is a major contributing factor (see, e.g., Yokel 2006).
  • Barbiturates have been shown to bind strongly to divalent metals, including Zn(ll) (see, e.g., Tochowicz et al., 2007; Breyholz et al., 2005; Wang, et al 201 1 ; Sheppeck et al., 2007a; Soong-Hoon Kim et al., 2005). This attribute has been widely used to develop drugs targeted against zinc-containing endopeptidases and a number of highly potent matrix metalloprotease inhibitors, with IC 50 values of ⁇ 10 nM, have been reported.
  • Barbiturates have also been used as zinc-binding groups to target drugs to a range of other enzymes, including TNFa converting enzyme (TACE) inhibitors (e.g., Sheppeck, et al 2007b; Duan,et al., 2007); TNFa has been shown to play a pivotal role in a range of inflammatory disorders and thus drugs which prevent its release are expected to show clinical utility in the treatment of diseases such as rheumatoid arthritis and inflammatory bowel disease.
  • TACE TNFa converting enzyme
  • barbiturate derivatives have also been shown to bind to a number of other divalent cations, for example, those found in the active site of methionine
  • aminopeptidase-1 including cobalt (see, e.g., Manas et al., 2008).
  • barbiturates form stable and soluble calcium salts, for example,
  • cyclobarbital calcium (CAS 143-76-0) and pentobarbital calcium (CAS 7563-42-0).
  • Barbiturates also form stable salts with cobalt(ll), nickel(ll) and copper(ll); the copper(ll) salts have been shown to retain anti-convulsant activity (see, e.g., Sevilla et al., 1992; Pezeshk, 1983).
  • Barbiturates bind strongly to the GABA A -receptor (see, e.g., Nogrady, 2005).
  • GABA is the most widespread inhibitory neurotransmitter in the brain.
  • Barbiturates have a general depressant action on the central nervous system by enhancing the action of GABA on the GABA A -receptor, a ligand-gated chloride channel (see, e.g., Olsen, 1986).
  • a number of drugs including phenobarbital, benzodiazepines, topiramate, vigabatrin and tiagabine are used for the treatment of epilepsy and act by enhancing the activation of GABA A - receptors, either directly or by inhibition of GABA metabolism or re-uptake.
  • GABA-producing enzyme glutamic acid decarboxylase (GAD67) and GABA are both decreased, whilst the a 2 subunit of GABA A receptor is selectively increased (see, e.g., Tamminga, 2007; Gray and Wroth, 2007).
  • Chandelier cells are GABA-ergic neurones which play a prominent role in modulating neuronal activity in regions featuring excitatory impulses, especially on pyramidal cells which are affected in schizophrenia.
  • the dopamine D 4 receptor is recognized to be of particular importance in schizophrenia, as certain effective therapeutic agents (e.g., clozapine) act upon it.
  • D 4 receptors are mainly located on chandelier neurones and pyramidal cells, it is highly likely that the GABA-ergic system plays a major role in the regulation of D 4 receptors and that the loss of these inhibitory GABA-ergic neurones, and the stability that they provide, plays a major role in the pathology of schizophrenia.
  • a number of 18 F radio-tracers for the PET imaging of Alzheimer's disease (AD) have been described and have entered clinical development, including florbetapir (Eli Lilly), florbetaben (Bayer) and flutemetamol (GE Healthcare) (shown below).
  • these compounds do not bind to metals or to the GABA A receptor (their mode of binding is via intercalation between the polypeptide sheets).
  • One aspect of the invention is an 18 F-fluorinated barbiturate compound
  • composition e.g., a pharmaceutical composition
  • a pharmaceutical composition comprising an 18 FBAR compound as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
  • a method of preparing a composition comprising the step of admixing an 18 FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
  • Another aspect of the invention is an 18 FBAR compound as described herein for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
  • positron emission imaging e.g., positron emission tomography (PET) imaging
  • PET positron emission tomography
  • Another aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
  • positron emission imaging e.g., positron emission tomography (PET) imaging
  • PET positron emission tomography
  • Another aspect of the invention is a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject which employs an 18 FBAR compound as described herein as an imaging agent.
  • PET positron emission tomography
  • Another aspect of the invention is an 18 FBAR compound as described herein for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
  • Another aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
  • Another aspect of the invention is a method of diagnosis or prognosis of a disease or disorder in a subject, which employs an 18 FBAR compound as described herein.
  • Another aspect of the invention is an 18 FBAR compound as described herein for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
  • Another aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
  • Another aspect of the invention is a method of therapeutic monitoring of a therapy for a disease or disorder in a subject undergoing said therapy, which employs an 18 FBAR compound as described herein.
  • the disease or disorder is a disease or disorder involving deposition of protein aggregates.
  • the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals.
  • the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates.
  • the disease or disorder is Alzheimer's disease (AD).
  • the disease or disorder is Parkinson's disease (PD).
  • PD Parkinson's disease
  • the disease or disorder is Huntington's disease (HD).
  • HD Huntington's disease
  • the disease or disorder is a disease or disorder involving
  • the disease or disorder is a disease or disorder involving changes in the expression level or distribution pattern of GABA A receptors.
  • the disease or disorder is epilepsy, schizophrenia, or a mood disorder (e.g., anxiety). In one embodiment, the disease or disorder is metal overdose or metal poisoning.
  • the disease or disorder is a disease or disorder associated with metal-induced leakiness of the blood-brain barrier.
  • Another aspect of the present invention is an 18 FBAR compound obtainable by a method of synthesis as described herein, or a method comprising a method of synthesis as described herein.
  • Another aspect of the present invention is an 18 FBAR compound obtained by a method of synthesis as described herein, or a method comprising a method of synthesis as described herein.
  • Another aspect of the present invention is a novel intermediate, as described herein, which is suitable for use in the methods of synthesis described herein.
  • Another aspect of the present invention is the use of such novel intermediates, as described herein, in the methods of synthesis described herein.
  • features and preferred embodiments of one aspect of the invention will also pertain to other aspects of the invention.
  • One aspect of the present invention relates to certain compounds which are related to barbituric acid (also referred to as pyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one):
  • All of the compounds of the present invention have a fluorinated substituent at the 5-position (denoted herein as -A 4 ), wherein at least one of the fluorine atoms of the fluorinated substituent is the radioactive isotope 18 F.
  • -A 1 is independently -H, -A 1A , or -A 1 B ; -A 1A is saturated aliphatic C 1 - 4 alkyl;
  • -A 1B is saturated C 3-6 cycloalkyl
  • -A 2 is independently -H, -A 2A , or -A 2B ;
  • -A 2A is saturated aliphatic C 1 - 4 alkyl
  • -A 2B is saturated C 3-6 cycloalkyl
  • -A 3 is independently -A 3A , -A 3B , -L 3 -A 3B , -A 3C , -L 3 -A 3C , -A 3D , -L 3 -A 3D , -A 3E , or -L 3 -A 3E ;
  • -A 3A is independently -A 3A1 , -A 3A2 , or -A 3A3 ;
  • -A 3A1 is saturated aliphatic Ci_i 0 alkyl, and is optionally substituted, for example, with one or more groups -R x ;
  • -A 3A2 is aliphatic C 2- ioalkenyl, and is optionally substituted, for example, with one or more groups -R x ;
  • -A 3A3 is aliphatic C 2- ioalkynyl, and is optionally substituted, for example, with one or more groups -R x ; each -A 3B is independently -A 3B1 or -A 3B2 ;
  • each -A 3B1 is saturated C 3 - 7 cycloalkyl, and is optionally substituted, for example, with one or more groups -R Y ;
  • each -A 3B2 is C 4-7 cycloalkenyl, and is optionally substituted, for example, with one or more groups -R Y ; each -A 3C phenyl, and is optionally substituted, for example, with one or more groups -R Y ; each -A 3D is C 5 - 6 heteroaryl, and is optionally substituted, for example, with one or more groups -R Y ; each -A 3E is non-aromatic C 4-7 heterocyclyl, and is optionally substituted, for example, with one or more groups -R Y ; each -L 3 - is saturated aliphatic Ci -4 alkylene; -A 4 is independently -A 4A , -A 4B , -L 4 -A 4B , -A 4C , -L 4 -A 4C , -A 4D , or -L 4 -A 4D ;
  • -A 4A is independently -A 4A1 , -A 4A2 , or -A 4A3 ;
  • -A 4A1 is saturated aliphatic C 1-10 alkyl substituted with one or more groups -R FA , and optionally is further substituted, for example, with one or more groups -R x ;
  • -A 4A2 is aliphatic C 2- ioalkenyl substituted with one or more groups -R FA , and optionally is further substituted, for example, with one or more groups -R x ;
  • -A is aliphatic C 2- ioalkynyl substituted with one or more groups -R optionally is further substituted, for example, with one or more groups -R x ;
  • each -A is independently -A 4m or -A ;
  • each -A 4B1 is saturated C 3-7 cycloalkyl substituted with one or more groups -R FB and optionally is further substituted, for example, with one or more groups -R Y ;
  • each -A 4B2 is C 4-7 cycloalkenyl substituted with one or more groups -R FB , and optionally is further substituted, for example, with one or more groups -R Y ; each -A 4C is phenyl substituted with one or more groups -R FC , and optionally is further substituted, for example, with one or more groups -R Y ; each -A is C 5 - 6 heteroaryl substituted with one or more groups -R
  • each -L 4 - is saturated aliphatic Ci -4 alkylene; each -R is -R ,
  • each -R FB is independently -R F1 or -R f
  • each -R FC is independently -R F1 or -R 1
  • each -R FD is independently -R F1 or -R 1 each -R F1 is an 18 F atom;
  • each -R F2 is a saturated aliphatic C 1-6 alkyl group substituted with one or more 18 F atoms; each -R , if present, is independently selected from:
  • each phenyl is optionally substituted with one or more groups
  • each -R ss is saturated aliphatic d ⁇ alkyl; and each -R Y , if present, is independently selected from:
  • each -R T is independently saturated aliphatic Ci -6 alkyl, phenyl, or
  • each phenyl is optionally substituted with one or more groups
  • each -R TT is saturated aliphatic Ci -4 alkyl.
  • a reference to an " 18 F atom" is intended to indicate that, in a sample of the compound, said atom is present as 18 F with an abundance of at least 25% (on a molar basis) relative to 18 0 (the isotope formed upon radioactive decay of 18 F).
  • said atom is present with an abundance of at least 50% (on a molar basis) related to 18 0. More preferably, said atom is present with an abundance of at least 75% (on a molar basis) related to 18 0. More preferably, said atom is present with an abundance of at least 85% (on a molar basis) related to 18 0. More preferably, said atom is present with an abundance of at least 90% (on a molar basis) related to 18 0. More preferably, said atom is present with an abundance of at least 95% (on a molar basis) related to 18 0.
  • aliphatic refers to linear and branched groups.
  • aliphatic refers to linear and branched groups.
  • aliphatic alkyl refers to linear and branched alkyl groups, but not alicyclic alkyl
  • -nBu is an example of a linear C 4 alkyl group
  • -iBu is an example of a branched C 4 alkyl group; in this way, both -nBu and -iBu are examples are aliphatic C 4 alkyl groups.
  • alkyl e.g., Ci-i 0 alkyl
  • Ethyl -CH 2 CH 3
  • C 2 alkyl group is an example of a C 2 alkyl group.
  • alkynyl e.g., C 2- ioalkynyl refers to groups that have at least one carbon- carbon triple bond.
  • Propargyl -CH 2 -C ⁇ CH is an example of a C 3 alkynyl group.
  • cycloalkyl e.g., C 3 - 7 cycloalkyl refers to groups that have no carbon-carbon double bonds, and no carbon-carbon triple bonds. Cyclohexyl is an example of a C 6 cycloalkyl group.
  • cycloalkenyl (e.g., C 4-7 cycloalkenyl) refers groups that have at least one carbon-carbon double bond, but no carbon-carbon triple bonds. Cyclohexenyl is an example of a C 6 cycloalkenyl group.
  • C 3-7 heterocyclyl refers to the number of ring atoms, which may be carbon atoms or heteroatoms (e.g., N, O, S).
  • pyridyl is an example of a
  • heteroaryl refers to a group that is attached to the rest of the molecule by an atom that is part of an aromatic ring, wherein the aromatic ring is part of an aromatic ring system, and the aromatic ring system has one or more heteroatoms (e.g., N, O, S).
  • heteroatoms e.g., N, O, S.
  • pyridyl is an example of a C 6 heteroaryl group
  • quinolyl is an example of a Cioheteroaryl group.
  • heterocyclyl refers to a group that is attached to the rest of the molecule by a ring atom that is not part of an aromatic ring (i.e., the ring is partially or fully saturated), and the ring contains one or more heteroatoms (e.g., N, O, S).
  • heteroatoms e.g., N, O, S.
  • piperidino is an example of a C 6 heterocyclyl group.
  • the carbon atom to which they are attached may be chiral, and if so, may independently be in the (R) or (S) configuration. Unless otherwise indicated, it is intended that both configurations are encompassed.
  • the configuration is (S). In one embodiment, the configuration is (R).
  • (61 ) A compound according to any one of (1 ) to (57), wherein -A 3A2 , if present, is aliphatic C 2-8 alkenyl, and is optionally substituted with one or more groups -R x .
  • (62) A compound according to any one of (1 ) to (57), wherein -A 3A2 , if present, is aliphatic C 2-8 alkenyl.
  • each -A 3B1 if present, is saturated C 4 - 6 cycloalkyl, and is optionally substituted with one or more groups -R Y .
  • each -A if present, is C 4-7 cycloalkenyl.
  • each -A if present, is independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl, and is optionally substituted with one or more groups -R Y .
  • each -A 3B2 is independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl.
  • each -A 3B2 if present, is C 5 - 6 cycloalkenyl.
  • each -A 3B2 if present, is independently cyclopentenyl or cyclohexenyl, and is optionally substituted with one or more groups -R Y .
  • each -A 3D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazoly
  • each -A 3D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazoly
  • each -A is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, and is optionally substituted with one or more groups -R Y .
  • each -A 3D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl.
  • each -A 3D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, and is optionally substituted with one or more groups -R Y .
  • each -A 3D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl.
  • each -A 3D is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, and is optionally substituted with one or more groups -R Y .
  • each -A is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl.
  • each -A 3E is independently pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, azepanyl, or diazepanyl, and is optionally substituted with one or more groups -R Y .
  • each -A is independently pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, azepanyl, or diazepanyl.
  • each -A 3E is independently pyrrolidino, piperidino, morpholino, piperazino, and is optionally substituted with one or more groups -R Y .
  • each -A 3E is independently pyrrolidino, piperidino, morpholino, piperazino, or N-(Ci- 4 alkyl)-piperazino.
  • the Group -L 3 - (132) A compound according to any one of (1 ) to (131 ), wherein each -L 3 -, if present, is independently -CH 2 -, -CH 2 CH 2 -, -CH(CH 3 )CH 2 -, -CH 2 CH(CH 3 )-, -C(CH 3 ) 2 -.
  • (201 ) A compound according to any one of (1 ) to (190), wherein -A 4A3 , if present, is aliphatic C 3-6 alkynyl substituted with one or more groups -R FA , and optionally is further substituted with one or more groups -R x .
  • (202) A compound according to any one of (1 ) to (190), wherein -A , if present, is aliphatic C 3 - 6 alkynyl substituted with one or more groups -R FA .
  • the Group -A ' (207) A compound according to any one of (1 ) to (206), wherein each -A , if present, is saturated C 3-7 cycloalkyl substituted with one or more groups -R FB , and optionally is further substituted with one or more groups -R Y .
  • each -A 4B1 if present, is saturated C 4 - 6 cycloalkyl substituted with one or more groups -R FB , and optionally is further substituted with one or more groups -R Y .
  • each -A 4B1 if present, is saturated C 5-6 cycloalkyl substituted with one or more groups -R FB , and optionally is further substituted with one or more groups -R Y .
  • each -A if present, is C 5-6 cycloalkenyl substituted with one or more groups -R FB , and optionally is further substituted with one or more groups -R Y .
  • each -A if present, is C 5 - 6 cycloalkenyl substituted with one or more groups -R FB .
  • each -A 4B2 if present, is independently cyclopentenyl or cyclohexenyl, substituted with one or more groups -R FB , and optionally is further substituted with one or more groups -R Y .
  • each -A 4B2 if present, is independently cyclopentenyl or cyclohexenyl, substituted with one or more groups -R FB .
  • the Group -A ' (240) A compound according to any one of (1 ) to (239), wherein each -A , if present, is C 5-6 heteroaryl substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -A 4D if present, is C 6 heteroaryl substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -A 4D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazoly
  • each -A 4D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazoly
  • each -A 4D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -A 4D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -R FD .
  • each -A 4D is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -A if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, substituted with one or more groups -R FD .
  • each -A if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -A 4D if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -R FD .
  • each -A if present, is pyridyl substituted with one or more groups -R FD , and is optionally substituted with one or more groups -R Y .
  • each -L 4 - is independently -CH 2 -, -CH 2 CH 2 -, -CH(CH 3 )CH 2 -, -CH 2 CH(CH 3 )-, -C(CH 3 ) 2 -.
  • the Group -R F2 (266) A compound according to any one of (1 ) to (265), wherein each -R F2 , if present, is a saturated aliphatic Ci -4 alkyl group substituted with one or more 18 F atoms.
  • each phenyl is optionally substituted with one or more groups
  • each -R ss is saturated aliphatic C ⁇ alkyl.
  • each -R x is independently selected from: -F, -CI, -Br, -I, -OH, and -OR s .
  • each -R x is independently selected from: -CI and -Br.
  • each -R T is independently saturated aliphatic Ci -6 alkyl, phenyl, or
  • each phenyl is optionally substituted with one or more groups
  • each -R TT is saturated aliphatic Ci -4 alkyl.
  • each -R Y is independently selected from: -F, -CI, -Br, -I, -R T , -CF 3 , phenyl, -OH, -OR T , -OCF 3 , -NH 2 , -NHR T , -NR T 2 , pyrrolidino, piperidino, morpholino, piperazino, and N-(Ci-4alkyl)-piperazino.
  • each -R Y is independently selected from: -F, -CI, -Br, -I, -R T , -OH, and -OR T .
  • each -R Y if present, is independently selected from: -F, -CI, -Br, -I, and -R T .
  • each -R Y if present, is independently selected from: -F, -CI, -Br, and -I.
  • the substantially purified form is at least 50% by weight, e.g., at least 60% by weight, e.g., at least 70% by weight, e.g., at least 80% by weight, e.g., at least 90% by weight, e.g., at least 95% by weight, e.g., at least 97% by weight, e.g., at least 98% by weight, e.g., at least 99% by weight.
  • the substantially purified form refers to the compound in any
  • the substantially purified form refers to a mixture of stereoisomers, i.e., purified with respect to other compounds. In one embodiment, the substantially purified form refers to one
  • the substantially purified form refers to a mixture of enantiomers. In one embodiment, the substantially purified form refers to a equimolar mixture of enantiomers (i.e., a racemic mixture, a racemate). In one embodiment, the substantially purified form refers to one enantiomer, e.g., optically pure enantiomer.
  • the contaminants represent no more than 50% by weight, e.g., no more than 40% by weight, e.g., no more than 30% by weight, e.g., no more than 20% by weight, e.g., no more than 10% by weight, e.g., no more than 5% by weight, e.g., no more than 3% by weight, e.g., no more than 2% by weight, e.g., no more than 1 % by weight.
  • the contaminants refer to other compounds, that is, other than stereoisomers or enantiomers. In one embodiment, the contaminants refer to other compounds and other stereoisomers. In one embodiment, the contaminants refer to other compounds and the other enantiomer.
  • the substantially purified form is at least 60% optically pure (i.e., 60% of the compound, on a molar basis, is the desired stereoisomer or enantiomer, and 40% is the undesired stereoisomer or enantiomer), e.g., at least 70% optically pure, e.g., at least 80% optically pure, e.g., at least 90% optically pure, e.g., at least 95% optically pure, e.g., at least 97% optically pure, e.g., at least 98% optically pure, e.g., at least 99% optically pure.
  • 60% optically pure i.e., 60% of the compound, on a molar basis, is the desired stereoisomer or enantiomer, and 40% is the undesired stereoisomer or enantiomer
  • at least 70% optically pure e.g., at least 80% optically pure, e.g., at least 90% optically pure, e
  • Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diastereoisomeric, epimeric, atropic, stereoisomeric, tautomeric, conformational, or anomeric forms, including but not limited to, cis- and trans-forms; E- and Z-forms; c-, t-, and r- forms; endo- and exo-forms; R-, S-, and meso-forms; D- and L-forms; d- and l-forms; (+) and (-) forms; keto-, enol-, and enolate-forms; syn- and anti-forms; synclinal- and anticlinal-forms; a- and ⁇ -forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as "isomers” (or "isomeric forms").
  • a reference to a class of structures may well include structurally isomeric forms falling within that class (e.g., C 1-7 alkyl includes n-propyl and iso-propyl; butyl includes n-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl).
  • C 1-7 alkyl includes n-propyl and iso-propyl
  • butyl includes n-, iso-, sec-, and tert-butyl
  • methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl
  • reference to a specifc group or substitution pattern is not intended to include other structural (or constitutional isomers) which differ with respect to the connections between atoms rather than by positions in space.
  • a reference to a methoxy group, -OCH 3 is not to be construed as a reference to its structural isomer, a
  • ortho-chlorophenyl is not to be construed as a reference to its structural isomer, meta-chlorophenyl.
  • keto/enol (illustrated below), imine/enamine, amide/imino alcohol, amidine/amidine, nitroso/oxime,
  • isotopic compounds with one or more isotopic substitutions, with the exception that: where 18 F is indicated, 18 F is specifically intended (and not some other isotope of fluorine).
  • H may be in any isotopic form, including 1 H, 2 H (D), and 3 H (T);
  • C may be in any isotopic form, including 12 C, 13 C, and 14 C;
  • O may be in any isotopic form, including 16 0 and 18 0; and the like.
  • a reference to a particular compound includes all such isomeric forms, including mixtures (e.g., racemic mixtures) thereof.
  • Methods for the preparation (e.g., asymmetric synthesis) and separation (e.g., fractional crystallisation and chromatographic means) of such isomeric forms are either known in the art or are readily obtained by adapting the methods taught herein, or known methods, in a known manner.
  • the ring core of the compounds has one or two secondary amino groups (-NH-).
  • One of these secondary amino groups may be de-protonated to give an anionic group (-N' " '-), which may form a salt with a suitable cation (e.g., Na + , K + ).
  • a suitable cation e.g., Na + , K +
  • barbiturates are prepared and handled as the sodium salt: see, e.g., Hexobarbital, Butabarbital sodium, Hexethal sodium, Pentobarbital sodium, Thiopental sodium, Vinbarbital sodium, and Secobarbital.
  • the term "pharmaceutically acceptable salt thereof” encompasses the following salts, wherein Z + is a suitable cation (e.g., Na + , K + ) or a suitable combination or sub-combination of cations (e.g., 1/2Ca 2+ ):
  • Z + is a suitable cation (e.g., Na + , K + ) or a suitable combination or sub-combination of cations (e.g., 1/2Ca 2+ ):
  • a salt may be formed with a suitable cation.
  • suitable inorganic cations include, but are not limited to, alkali metal ions such as Na + and K + , alkaline earth cations such as Ca 2+ and Mg 2+ , and other cations such as ⁇ 3 .
  • suitable organic cations include, but are not limited to, ammonium ion (i.e., NH 4 + ) and substituted ammonium ions (e.g., NH 3 R + , NH 2 R2 + , NHR 3 + , NR 4 + ).
  • suitable substituted ammonium ions are those derived from:
  • ethylamine diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine.
  • An example of a common quaternary ammonium ion is N(CH 3 ) 4 + .
  • a salt may be formed with a suitable anion.
  • suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids: hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfurous, nitric, nitrous, phosphoric, and phosphorous.
  • Suitable organic anions include, but are not limited to, those derived from the following organic acids: 2-acetyoxybenzoic, acetic, trifluoroacetic, ascorbic, aspartic, benzoic, camphorsulfonic, cinnamic, citric, edetic, ethanedisulfonic, ethanesulfonic, fumaric, glucheptonic, gluconic, glutamic, glycolic, hydroxymaleic, hydroxynaphthalene carboxylic, isethionic, lactic, lactobionic, lauric, maleic, malic, methanesulfonic, mucic, oleic, oxalic, palmitic, pamoic, pantothenic, phenylacetic, phenylsulfonic, propionic, pyruvic, salicylic, stearic, succinic, sulfanilic, tartaric, toluenesulfonic, and valeric.
  • a reference to a particular compound also includes salt forms thereof.
  • solvate is used herein in the conventional sense to refer to a complex of solute (e.g., compound, salt of compound) and solvent. If the solvent is water, the solvate may be conveniently referred to as a hydrate, for example, a mono-hydrate, a di-hydrate, a tri-hydrate, etc. Unless otherwise specified, a reference to a particular compound also includes solvate and hydrate forms thereof.
  • Chemically Protected Forms It may be convenient or desirable to prepare, purify, and/or handle the compound in a chemically protected form.
  • the term "chemically protected form” is used herein in the conventional chemical sense and pertains to a compound in which one or more reactive functional groups are protected from undesirable chemical reactions under specified conditions (e.g., pH, temperature, radiation, solvent, and the like). In practice, well known chemical methods are employed to reversibly render unreactive a functional group, which otherwise would be reactive, under specified conditions.
  • one or more reactive functional groups are in the form of a protected or protecting group (also known as a masked or masking group or a blocked or blocking group).
  • a compound which has two nonequivalent reactive functional groups may be derivatized to render one of the functional groups "protected,” and therefore unreactive, under the specified conditions; so protected, the compound may be used as a reactant which has effectively only one reactive functional group.
  • the protected group may be "deprotected" to return it to its original functionality.
  • a hydroxy group may be protected as an ether (-OR) or an ester
  • the aldehyde or ketone group is readily regenerated, for example, by hydrolysis using water in the presence of acid.
  • an amine group may be protected, for example, as an amide (-NRCO-R) or a urethane (-NRCO-OR), for example, as: a methyl amide (-NHCO-CH 3 ); a benzyloxy amide (-NHCO-OCH 2 C 6 H 5 , -NH-Cbz); as a t-butoxy amide (-NHCO-OC(CH 3 ) 3 , -NH-Boc); a 2-biphenyl-2-propoxy amide -NH-Bpoc), as a
  • 9-fluorenylmethoxy amide (-NH-Fmoc), as a 6-nitroveratryloxy amide (-NH-Nvoc), as a 2-trimethylsilylethyloxy amide (-NH-Teoc), as a 2,2,2-trichloroethyloxy amide (-NH-Troc), as an allyloxy amide (-NH-Alloc), as a 2(-phenylsulfonyl)ethyloxy amide (-NH-Psec); or, in suitable cases (e.g., cyclic amines), as a nitroxide radical (> ⁇ -0 ⁇ ).
  • a carboxylic acid group may be protected as an ester for example, as: an Ci -7 alkyl ester (e.g., a methyl ester; a t-butyl ester); a Ci -7 haloalkyl ester (e.g., a
  • C 1-7 trihaloalkyl ester a triC 1-7 alkylsilyl-C 1-7 alkyl ester; or a C 5-2 oaryl-C 1-7 alkyl ester (e.g., a benzyl ester; a nitrobenzyl ester); or as an amide, for example, as a methyl amide.
  • an appropriate mono-substituted diethyl malonate is deprotonated and reacted with a suitably protected bromoalcohol, to give a di-substituted diethyl malonate, which is then cyclised with a suitable urea to give the 5,5'-disubstituted barbiturate.
  • the protecting group is then removed from the alcohol and a suitable leaving group is introduced and then displaced with suitably activated 18 F-fluoride.
  • diethyl 2-ethylmalonate is deprotected with sodium hydride in a solvent such as DMF and reacted with a benzyl-protected bromoalcohol.
  • the resulting diethylmalonate is then reacted with urea in dry DMF and the benzyl protecting group removed by hydrogenation, for example, with 20 % palladium (II) hydroxide on carbon in a solvent such as methanol.
  • the alcohol is then reacted with toluenesulfonyl chloride, for example, in a solvent such as chloroform containing a suitable base, for example, pyridine.
  • the tosyl group is displaced by K 18 F in the presence of a suitable phase-transfer agent, for example, Kryptofix 222®, in a suitable solvent, for example, acetonitrile, to give the target 18 F labelled compound.
  • a suitable phase-transfer agent for example, Kryptofix 222®
  • a suitable solvent for example, acetonitrile
  • the corresponding F compound is prepared as an analytical standard to allow characterisation of the corresponding 18 F compound.
  • the alcohol is prepared as described in Scheme 1 above, and then reacted with a suitable fluorinating agent at low temperature, for example, with diethylaminosulfur trifluoride (DAST) in a suitable solvent, for example, chloroform at -4°C or dimethoxyethane (DME) at -78°C.
  • DAST diethylaminosulfur trifluoride
  • DME dimethoxyethane
  • the corresponding thio-compound is prepared by following a methodology similar to the one shown in Scheme 1 above, and using a suitable thiourea and a suitable alcohol protecting group, that is, one which can be removed under conditions not affected by the presence of sulfur, for example, a methoxymethylether, i-butyldiphenyl silyl ether (OTBDPS), f-butyldimethyl silyl ether (OTBDMS) or tetrahydropyranyl ether (OTHP), which can be removed by reaction of the bromoalcohol with methoxymethyl chloride, i-butyldiphenyl silyl chloride, or dihydropyran, respectively.
  • a suitable thiourea and a suitable alcohol protecting group that is, one which can be removed under conditions not affected by the presence of sulfur, for example, a methoxymethylether, i-butyldiphenyl silyl ether (OTBDPS), f-butyldimethyl silyl
  • the hydroxyl protecting group is then removed; for example, the silyl ether group is removed by reaction with tert-butylammonium fluoride, and the tetrahydropyranyl group and methoxymethyl ether are removed under acidic conditions (e.g., HCI).
  • the alcohol derivative is then used to prepare the 18 F or 19 F compounds as shown in Schemes 1 and 2 above.
  • Other methods for protection and deprotection of alcohols are described, for example, in Greene and Wuts, Protective Groups in Organic Synthesis, 1999, J. Wiley, New York, pp. 23-148.
  • the starting mono-substituted diethyl malonate is prepared by reaction of diethyl malonate with an appropriately substituted alkyl halide or tosylate.
  • diethyl malonate is deprotonated with sodium hydride in dry DMF and reacted with an alkyl bromide, for example, a branched alkyl bromide or cycloalkyi bromide.
  • the mono-substituted diethyl malonate is then further reacted as described in the above schemes.
  • the starting mono-substituted dialkyl malonate is prepared by reaction of an appropriate ethyl ester with diethyl carbonate.
  • ethyl ester for example, ethyl
  • 4-methylpentanoate is deprotonated with LDA in dry THF and reacted with
  • diethylcarbonate to give the appropriately mono-substituted diethyl malonate, which then further reacted as described in the above schemes to give the corresponding fluorinated compound.
  • substituents are introduced onto the nitrogen atoms of the barbiturate or thiobarbiturate ring by the use of an appropriately mono- or di-substituted urea or thiourea.
  • A/-methylurea, A/-phenylthiourea or /V,/V-dimethylurea may be used.
  • substituents are introduced onto the nitrogen atoms of the barbiturate or thiobarbiturate ring by deprotonation and reaction with an appropriate alkyl or aryl group bearing a suitable leaving group.
  • the barbiturate or thiobarbiturate is deprotonated with sodium hydride in dry DMF and then reacted with one equivalent of an alkyl halide, mesylate, triflate or tosylate. The process may be repeated to introduce a second different substituent.
  • the compounds produced are then further reacted as described in the above schemes in order to give the corresponding fluorinated compounds.
  • the fluorine atom is introduced onto an aryl group, for example, by reduction of an aromatic nitro group to give an aromatic amine, which is then trimethylated to give a quarternary ammonium cation, which is then displaced by a suitably activated fluoride anion.
  • the nitro group can be reduced with H 2 /10% palladium on carbon and the amine methylated with methyl iodide in excess in the presence of a suitable base such as potassium carbonate, in a suitable solvent such as DMF.
  • the quarternary ammonium cation is displaced with K 18 F in a solvent such as DMSO or acetonitrile at high temperatures, for example, 120-140°C.
  • compositions One aspect of the present invention is a composition (e.g., a pharmaceutical composition) comprising an 18 FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
  • a composition e.g., a pharmaceutical composition
  • a pharmaceutical composition comprising an 18 FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
  • compositions e.g., a pharmaceutical composition
  • a composition comprising admixing an 18 FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
  • the 18 FBAR compounds described herein are useful, for example, as imaging agents in positron emission imaging, for example, positron emission tomography (PET) imaging.
  • PET positron emission tomography
  • Such positron emission imaging e.g., PET imaging
  • PET imaging is useful, for example, in methods of diagnosis, prognosis, and therapeutic monitoring.
  • One aspect of the invention is an 18 FBAR compound as described herein for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
  • positron emission imaging e.g., positron emission tomography (PET) imaging
  • PET positron emission tomography
  • One aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
  • positron emission imaging e.g., positron emission tomography (PET) imaging
  • PET positron emission tomography
  • One aspect of the invention is a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject employing an 18 FBAR compound as described herein as an imaging agent.
  • PET positron emission tomography
  • the method of positron emission imaging comprises the following steps:
  • the step of: (i) introducing the 18 FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18 FBAR compound (preferably as part of a pharmaceutically acceptable composition).
  • the term "effective amount” pertains to that amount of the 18 FBAR compound, or a material, composition or dosage form comprising the 18 FBAR compound, which is effective for producing some desired imaging effect, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
  • the step of: (ii) imaging the subject is the step of: (ii) determining the presence and/or location and/or amount of 18 FBAR compound in (e.g., a part of, the whole of) the subject using positron emission (e.g., using PET) imaging.
  • positron emission e.g., using PET
  • PET imaging Methods of PET imaging are well known. See, for example, Pimlott et al., 201 1 ;
  • One aspect of the invention is an 18 FBAR compound as described herein for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
  • the 18 FBAR compound is for use in a method of diagnosis.
  • the 18 FBAR compound is for use in a method of prognosis.
  • the method of diagnosis or prognosis is practised on the human or animal body of the subject.
  • One aspect of the invention is an 18 FBAR compound as described herein for use as a diagnostic or prognostic agent.
  • One aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
  • the medicament is for use in a method of diagnosis.
  • the medicament is for use in a method of prognosis.
  • One aspect of the invention is a method of diagnosis or prognosis of a disease or disorder in a subject which employs an 18 FBAR compound as described herein.
  • the method is a method of diagnosis. In one embodiment, the method is a method of prognosis. ln one embodiment, the method of diagnosis or prognosis comprises the following steps:
  • the step of: (i) introducing the 18 FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18 FBAR compound (preferably as part of a pharmaceutically acceptable composition).
  • the term "effective amount” pertains to that amount of the 18 FBAR compound, or a material, composition or dosage form comprising the 18 FBAR compound, which is effective for permitting some desired determination of the presence and/or location and/or amount of 18 FBAR compound in the subject, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
  • the determination of the presence and/or location and/or amount of 18 FBAR compound in the subject is by positron emission (e.g., PET) imaging.
  • positron emission e.g., PET
  • One aspect of the invention is an 18 FBAR compound as described herein for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
  • the method of therapeutic monitoring is practised on the human or animal body.
  • One aspect of the invention is use of an 18 FBAR compound as described herein in the manufacture of a medicament for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
  • One aspect of the invention is a method of therapeutic monitoring of a therapy for a disease or disorder in a subject undergoing said therapy which employs an 18 FBAR compound as described herein. ln one embodiment, the method of therapeutic monitoring comprises the following steps:
  • undergoing therapy is intended to mean about to undergo the therapy, currently undergoing the therapy, or (recently) completed the therapy.
  • the step of: (i) introducing the 18 FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18 FBAR compound (preferably as part of a pharmaceutically acceptable composition).
  • an effective amount pertains to that amount of the 18 FBAR compound, or a material, composition or dosage form comprising the 18 FBAR compound, which is effective for permitting some desired determination of the presence and/or location and/or amount of 18 FBAR compound in the subject, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
  • the determination of the presence and/or location and/or amount of 18 FBAR compound in the subject is by positron emission (e.g., PET) imaging.
  • positron emission e.g., PET
  • the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals. In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates.
  • the disease or disorder is Alzheimer's disease (AD); Parkinson's disease (PD); Huntington's disease (HD); amyotrophic lateral sclerosis (ALS);
  • AD Alzheimer's disease
  • PD Parkinson's disease
  • HD Huntington's disease
  • ALS amyotrophic lateral sclerosis
  • CJD Creutzfeldt-Jakob disease
  • MS multiple sclerosis
  • Friedreich's ataxia Wilson's disease
  • Hallervorden-Spatz syndrome Creutzfeldt-Jakob disease
  • the disease or disorder is Alzheimer's disease (AD).
  • AD Alzheimer's disease
  • the disease or disorder is Parkinson's disease (PD). ln one embodiment, the disease or disorder is Huntington's disease (HD). Diseases and Disorders: Conditions Relating to Protein Aggregates
  • the disease or disorder is a disease or disorder involving deposition of protein aggregates.
  • the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates.
  • the disease or disorder is an amyloidosis, a tauopathy,
  • a synucleinopathy or a prion disease or disorder.
  • the disease or disorder is an amyloidosis, for example: Alzheimer's disease (AD); Down's syndrome; hereditary cerebral haemorrhage with amyloidosis; Gerstmann-Straussler-Scheinker disease; fatal familial insomnia; hereditary cerebral hemorrhage with amyloidosis (Icelandic); familial dementia (also referred to as cerebral amyloidosis, British & Danish types); familial amyloid neuropathy; or Finnish type amyloidosis.
  • AD Alzheimer's disease
  • Down's syndrome hereditary cerebral haemorrhage with amyloidosis
  • Gerstmann-Straussler-Scheinker disease fatal familial insomnia
  • hereditary cerebral hemorrhage with amyloidosis Icelandic
  • familial dementia also referred to as cerebral amyloidosis, British & Danish types
  • familial amyloid neuropathy or Finnish type amyloidosis.
  • the disease or disorder is a tauopathy, for example: Alzheimer's disease (AD); amyotrophic lateral sclerosis/parkinsonism-dementia complex; argyrophilic grain dementia; corticobasal degeneration; Creutzfeldt-Jakob disease (CJD); dementia pugilistica; diffuse neurofibrillary tangles with calcification; Down's syndrome;
  • AD Alzheimer's disease
  • amyotrophic lateral sclerosis/parkinsonism-dementia complex argyrophilic grain dementia
  • corticobasal degeneration Creutzfeldt-Jakob disease (CJD)
  • CJD Creutzfeldt-Jakob disease
  • dementia pugilistica diffuse neurofibrillary tangles with calcification
  • Down's syndrome a tauopathy
  • FTDP17 frontotemporal dementia with parkinsonism linked to chromosome 17
  • Gerstmann-Straussler-Scheinker disease Hallevorden-Spatz disease; inclusion-body myositis; multiple system atrophy; myotonic dystrophy; Niemann-Pick disease, type C; non-Guamanian motor neuron disease with neurofibrillary tangles; Pick's disease;
  • the disease or disorder is a synucleinopathy, for example:
  • Parkinson's disease dementia with Lewy bodies (DLB); pure autonomic failure (PAF); multiple system atrophy (MSA); or Hallervorden-Spatz disease.
  • the disease or disorder is prion disease or disorder, for example: Creutzfeldt-Jakob disease (CJD); variant Creutzfeldt-Jakob disease; Gerstmann- Straussler-Scheinker disease; Fatal familial insomnia; or Kuru (in humans) or scrapie; Bovine Spongiform Encephalopathy (BSE); transmissible mink encephalopathy; feline spongiform encephalopathy; ungulate spongiform encephalopathy; or chronic wasting disease (CWD) (in animals).
  • the disease or disorder is Alzheimer's disease (AD).
  • the disease or disorder is Parkinson's disease (PD).
  • PD Parkinson's disease
  • the disease or disorder is Huntington's disease (HD).
  • HD Huntington's disease
  • the disease or disorder is a disease or disorder involving dis-regulation of a GABA A receptor.
  • the disease or disorder is a disease or disorder involving changes in the expression level or distribution pattern of GABA A receptors.
  • the disease or disorder is epilepsy, schizophrenia, a mood disorder (e.g., anxiety), autism, attention deficit hyperactivity disorder (ADHD), or a
  • neurodegenerative disorder e.g., Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD)
  • AD Alzheimer's disease
  • PD Parkinson's disease
  • HD Huntington's disease
  • the disease or disorder is epilepsy, schizophrenia, a mood disorder (e.g., anxiety), autism, or attention deficit hyperactivity disorder (ADHD).
  • a mood disorder e.g., anxiety
  • autism e.g., autism
  • ADHD attention deficit hyperactivity disorder
  • the disease or disorder is epilepsy, schizophrenia, or a mood disorder (e.g., anxiety). In one embodiment, the disease or disorder is epilepsy.
  • the disease or disorder is schizophrenia.
  • the disease or disorder is a mood disorder (e.g., anxiety).
  • a mood disorder e.g., anxiety
  • the disease or disorder is anxiety.
  • the disease or disorder is metal overdose or metal poisoning.
  • the disease or disorder is metal overdose. ln one embodiment, the disease or disorder is metal poisoning.
  • the metal is iron (e.g., iron overdose).
  • the metal is lead (e.g., lead poisoning).
  • the metal is mercury (e.g., mercury poisoning).
  • the metal is cadmium (e.g., cadmium poisoning).
  • the disease or disorder is a disease or disorder associated with metal-induced leakiness of the blood-brain barrier.
  • the disease or disorder is metal-induced leakiness of the blood-brain barrier.
  • the disease or disorder is multiple sclerosis (MS) or Parkinson's disease (PD).
  • MS multiple sclerosis
  • PD Parkinson's disease
  • the disease or disorder is multiple sclerosis (MS).
  • the disease or disorder is Parkinson's disease (PD).
  • PD Parkinson's disease
  • positron emission imaging methods described herein may be combined with other diagnostic and/or imaging methods.
  • positron emission imaging methods described herein may be combined with x-ray computed tomography (CT) methods to provide improved diagnosis, prognosis, therapeutic monitoring, etc.
  • CT x-ray computed tomography
  • the 18 FBAR compounds described herein may also be used as part of an in vitro assay, for example, in order to determine whether if a candidate 18 FBAR compound binds to a particular protein aggregate, etc.
  • the 18 FBAR compounds described herein may also be used as a standard, for example, in an assay, in order to identify other compounds, other PET imaging agents, etc. Kits
  • kits comprising (a) an 18 FBAR compound as described herein, or a composition comprising an 18 FBAR compound as described herein, e.g., preferably provided in a suitable container and/or with suitable packaging; and (b) instructions for use, e.g., written instructions on how to administer the compound or composition.
  • the written instructions may also instructions regarding subsequent positron emission (e.g., PET) imaging and/or a list of indications for which the compound or composition may be used in, e.g., a method of diagnosis, prognosis, therapeutic monitoring, etc.
  • the 18 FBAR compound or pharmaceutical composition comprising the 18 FBAR compound may be administered to a subject by any convenient and appropriate route of
  • a preferred route of administration parenteral for example, by injection, including subcutaneous, intradermal, intramuscular, intravenous, intraarterial, intracardiac, intrathecal, intraspinal, intracapsular, subcapsular, intraorbital, intraperitoneal, intratracheal, subcuticular, intraarticular, subarachnoid, and intrasternal.
  • the subject/patient may be a mammal, a rodent (e.g., a guinea pig, a hamster, a rat, a mouse), murine (e.g., a mouse), a lagomorph (e.g., a rabbit), avian (e.g., a bird), canine (e.g., a dog), feline (e.g., a cat), equine (e.g., a horse), porcine (e.g., a pig), ovine (e.g., a sheep), bovine (e.g., a cow), a primate, simian (e.g., a monkey or ape), a monkey
  • a rodent e.g., a guinea pig, a hamster, a rat, a mouse
  • murine e.g., a mouse
  • a lagomorph e.g., a rabbit
  • ape e.g., gorilla, chimpanzee, orangutang, gibbon
  • a human e.g., gorilla, chimpanzee, orangutang, gibbon
  • the subject/patient may be any of its forms of development, for example, a foetus.
  • the subject/patient is a human.
  • the 18 FBAR compound While it is possible for the 18 FBAR compound to be administered alone, it is preferable to present it as a pharmaceutical formulation (e.g., composition, preparation, medicament) comprising at least one 18 FBAR compound, as described herein, together with one or more other pharmaceutically acceptable ingredients well known to those skilled in the art, including, but not limited to, pharmaceutically acceptable carriers, diluents, excipients, adjuvants, fillers, buffers, preservatives, anti-oxidants, lubricants, stabilisers, solubilisers, surfactants (e.g., wetting agents), masking agents, colouring agents, flavouring agents, and sweetening agents.
  • the formulation may further comprise other active agents, for example, other therapeutic or prophylactic agents.
  • the present invention further provides pharmaceutical compositions, as defined above, and methods of making a pharmaceutical composition comprising admixing at least one 18 FBAR compound, as described herein, together with one or more other pharmaceutically acceptable ingredients well known to those skilled in the art, e.g., carriers, diluents, excipients, etc. If formulated as discrete units (e.g., ampoules, etc.), each unit contains a predetermined amount (dosage) of the compound.
  • pharmaceutically acceptable pertains to compounds, ingredients, materials, compositions, dosage forms, etc., which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of the subject in question (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.
  • Each carrier, diluent, excipient, etc. must also be “acceptable” in the sense of being compatible with the other ingredients of the formulation.
  • Suitable carriers, diluents, excipients, etc. can be found in standard pharmaceutical texts, for example, Remington's Pharmaceutical Sciences, 18th edition, Mack Publishing Company, Easton, Pa., 1990; and Handbook of Pharmaceutical Excipients, 5th edition, 2005.
  • the formulations may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the compound with a carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the compound with carriers (e.g., liquid carriers, finely divided solid carrier, etc.), and then shaping the product, if necessary.
  • a preferred formulation is in the form of a liquid, solution (e.g., aqueous, non-aqueous), suspension (e.g., aqueous, non-aqueous), or emulsion (e.g., oil-in-water, water-in-oil).
  • the compound may be dissolved in, suspended in, or admixed with one or more other pharmaceutically acceptable ingredients.
  • the compound may be presented in a liposome or other microparticulate which is designed to target the compound, for example, to one or more organs.
  • Formulations suitable for parenteral administration include aqueous or non-aqueous, isotonic, pyrogen-free, sterile liquids (e.g., solutions, suspensions), in which the compound is dissolved, suspended, or otherwise provided (e.g., in a liposome or other microparticulate).
  • sterile liquids e.g., solutions, suspensions
  • Such liquids may additional contain other pharmaceutically acceptable ingredients, such as anti-oxidants, buffers, preservatives, stabilisers, bacteriostats, suspending agents, thickening agents, and solutes which render the formulation isotonic with the blood (or other relevant bodily fluid) of the intended recipient.
  • excipients include, for example, water, alcohols, polyols, glycerol, vegetable oils, and the like.
  • suitable isotonic carriers for use in such formulations include Sodium Chloride Injection, Ringer's Solution, or Lactated Ringer's Injection.
  • the concentration of the compound in the liquid is from about 1 ng/mL to about 10 ⁇ g/mL.
  • the formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored under suitable conditions prior to use.
  • appropriate dosages of the 18 FBAR compounds, and compositions comprising the 18 FBAR compounds can vary from subject to subject. Determining the optimal dosage will generally involve the balancing of the level of benefit effect (e.g., diagnosis, prognosis, therapeutic monitoring) against any risk or deleterious side effects.
  • the selected dosage level will depend on a variety of factors including, but not limited to, the binding affinity of the particular 18 FBAR compound, the route of administration, the time of administration, the rate of excretion of the 18 FBAR compound, the duration of the procedure (e.g., imaging process), other drugs,
  • administration will ultimately be at the discretion of the physician, veterinarian, or clinician, although generally the dosage will be selected to achieve local concentrations at the site of action which achieve the desired effect without causing substantial harmful or deleterious side-effects.
  • Administration can be effected in one dose, continuously or intermittently (e.g., in divided doses at appropriate intervals) throughout the course of the procedure. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used, the purpose of the procedure, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician, veterinarian, or clinician.
  • a suitable dose of the 18 FBAR compound is in the range of about 0.1 ⁇ g to about 5 ⁇ g for a single positron emission scan of an adult human subject.
  • the normal dose of the 18 FBAR compound for a single positron emission scan of an adult human subject, in terms of activity, is about 140 MBq (5 mSv).
  • the amount administered is calculated on the basis of the parent compound and so the actual weight to be used is increased proportionately.
  • reaction mixture was quenched with a saturated aqueous NH 4 CI solution and extracted with small portions of diethyl ether.
  • the collected organic phases were dried over anhydrous Na 2 S0 4 , filtered and the solvent was removed in vacuo.
  • the residue was purified by flash chromatography on silica gel (CH 2 CI 2 ) to give 3.444 g of the title compound (91 %) as a yellow oil.
  • Ci2H 19 FN 2 Na0 3 281 .1 found: 259.1 , 281.1 .
  • Route B Yield optimized: To a solution of 5-ethyl-5-(6-hydroxyhexyl)pyrimidine- 2,4,6(1 H,3H,5H)-trione (3) (250 mg, 1.0 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (8 mL) diethylaminosulfur trifluoride (DAST) (99%, 260 ⁇ _, 2.0 mmol, 2 eq) was added at -78°C. The reaction mixture was stirred at this temperature for 15 minutes under nitrogen atmosphere and then it was allowed to warm to room temperature. After 4.5 hours water was added and the mixture was extracted with diethyl ether.
  • DME dry 1 ,2-dimethoxyethane
  • DAST diethylaminosulfur trifluoride
  • the product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 ⁇ , flow rate 1 mL/min, solvent A: H 2 0 + 0.1 % TFA, solvent B: CH 3 CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes.
  • Method B [ 18 F]Fluoride was produced by CTI RDS-1 1 1 cyclotron (CTI/Siemens) via the 18 0(p,n) 18 F nuclear reaction by bombardment of isotopically enriched [ 18 0]H 2 0 target and passed through a Chromafix® 30-PS-HCO3 cartridge (Macherey Nagel) as an aqueous solution in 18 0-enriched water.
  • [ 18 F]F " was eluted from the cartridge with 0.5 mL of K 2 C0 3 solution in water (6 mg/mL) into a reaction vessel in the hot cell. Then a solution of Kryptofix® 222 (15 mg) in dry CH 3 CN (1 mL) was added.
  • the identity of the 18 F labelled product was confirmed by co-injection with the 19 F cold standard 5-ethyl-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one (4) on the same column.
  • the product was solubilised in CH 3 CN and analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 ⁇ (0.44 MBq), flow rate 1 mL/min, solvent A: H 2 0, solvent B: CH 3 CN, gradient: 40%- 95% B in 15 minutes.
  • the retention time in the UV-chromatogram was identical to the retention time of 5-ethyl-5-(6-[ 18 F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (6) in the radioactivity chromatogram.
  • the identity of the 18 F labelled product was confirmed by co-injection with the 19 F cold standard 5-(6-fluorohexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one (10) on the same column.
  • the product was solubilised in CH 3 CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x I D), volume injected 20 ⁇ _, flow rate 1 mL/min, solvent A: H 2 0 + 0.1 % TFA, solvent B: CH 3 CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes.
  • the retention time in the UV-chromatogram was identical to the retention time of 5-(6-[ 18 F]fluorohexyl)- 5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one (12) in the radioactivity chromatogram.
  • reaction mixture was quenched with a saturated aqueous NH 4 CI solution and extracted with small portions of diethyl ether.
  • the collected organic phases were dried over anhydrous Na 2 S0 4 , filtered and the solvent was removed in vacuo.
  • the residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9:1 ) to give 3.165 g of 13 (92%) as a pale yellow oil.
  • DME dry 1 ,2-dimethoxyethane
  • DAST diethylaminosulfur trifluoride
  • the product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 ⁇ , flow rate 1 mL/min, solvent A: H 2 0 + 0.1 % TFA, solvent B: CH 3 CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes.
  • the product was solubilised in CH 3 CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 ⁇ , flow rate 1 mL/min, solvent A: H 2 0 + 0.1 % TFA, solvent B: CH 3 CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes.
  • the retention time in the UV-chromatogram was identical to the retention time of 5-benzyl-5-(6- [ 18 F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr ⁇ one (18) in the radioactivity chromatogram.
  • DME dry 1 ,2-dimethoxyethane
  • DAST diethylaminosulfur trifluoride
  • reaction mixture was quenched with a saturated aqueous NH 4 CI solution and extracted with small portions of diethyl ether.
  • the collected organic phases were dried over anhydrous Na 2 S0 4 , filtered and the solvent was removed in vacuo.
  • the residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 8.5:1 .5) to give 172 mg of 28 (44%) as a pale yellow oil.
  • R f 0.22 (n-Hex/EtOAc 9:1 ).
  • the product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 ⁇ , 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 ⁇ , flow rate 1 mL/min, solvent A: H 2 O+0.1 %TFA, solvent B: CH 3 CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min.
  • reaction mixture was acidified with 1 N HCI, diluted with water and extracted with small portions of diethyl ether.
  • the combined organic extracts were dried over anhydrous Na 2 S0 4 , filtered and the solvent was removed in vacuo.
  • the residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 4:1 ) to afford 33 mg of 33 as white solid (44%).
  • reaction mixture was quenched with a saturated aqueous NH 4 CI solution and extracted with small portions of diethyl ether.
  • the collected organic phases were dried over anhydrous Na 2 S0 4 , filtered and the solvent was removed in vacuo.
  • the residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9.5:0.5 to n-Hex/EtOAc 9:1 ) to give 3.024 g of 35 (75%) as a pale yellow oil.
  • R f 0.29 (n-Hex/EtOAc 9.5:0.5).
  • DAST diethylaminosulfur trifluoride
  • Thioflavin T Displacement Assay
  • Thioflavin T is a dye commonly used to quantify the presence of amyloid fibrils. ThT has no intrinsic fluorescence, and thus shows only minimal emission in the absence of binding, but specifically binds to ⁇ amyloid fibrils giving strong fluorescence and a ten-fold increase in emission. Binding results in a fluorescent signal with emission at 485 nm, upon excitation at 440 nM, the intensity of which is directly proportional to the mass of the formed fibril.
  • the affinity of a test compound for ⁇ amyloid can be measured by determining its ability to displace bound ThT and observing the resultant decrease in fluorescence. The more strongly a compound binds to ⁇ amyloid, the greater the reduction in fluorescence seen.
  • PET Positron Emission Tomography
  • CT Computed Tomography
  • MRI Magnetic Resonance Imaging
  • the combined PET/CT technique provides complete information both on disease location and metabolism. This means that small lesions such as tangles and ⁇ plaques, which may not show anatomical changes in size or shape, could be detected with PET (high sensitivity) and then exactly located with CT (high resolution).
  • a suitable tracer labelled with a positron-emitting isotope is administered to the subject, typically parenterally (e.g., by intravenous injection, intravenous infusion, etc.).
  • the tracer accumulates in the region of the body under study. It decays by positron emission.
  • the emitted positron ( ⁇ +) travels a short distance in the surrounding tissue before it is annihilated by interaction with an electron.
  • the distance travelled by the positron before annihilation is called the "positron range”.
  • the path length is determined by the energy of the emitted positron, which is different for each positron-emitting radionuclide.
  • the annihilation of positron with electron produces two gamma ray photons ( ⁇ ) that travel in opposite directions (i.e., each at an angle of 180° with respect to the other).
  • ⁇ gamma ray photons
  • the detection of these two gamma ray photons by the detector ring of the PET scanner allows the localisation of the radiotracer in the body.
  • a computer is used to create a series of images that use different colours or degrees of brightness to show the different distribution of the labelled probe within the body as a function of time.
  • mice transgenic mice or wild-type controls were fasted overnight, injected intraperitoneally or intravenously with 18 F-labelled test compound (range: 9.84-17.32 MBq in 0.33 - 0.5 ml.) while conscious. Uptake occurred in the dark over 45 minutes with free access to drinking water. Mice were kept warm by placing the cage on a heating pad (35°C) and warming started at least 30 minutes before 18 F-labelled test compound administration and continued during the 18 F-labelled test compound uptake period.
  • 18 F-labelled test compound range: 9.84-17.32 MBq in 0.33 - 0.5 ml.
  • mice were anesthetised with ketamine 100 mg/mL (Vetalar * V®) / medetomidine 1 mg/mL (Domitor®) / sterile water solution), and placed on the bed of the scanner in supine position (head first). The body and the head of the mouse were secured to the bed with tape.
  • CT and PET data were collected using a Suinsa ARGUS dual-ring PET/CT scanner, housed in a temperature-controlled room. Thirty-six position-sensitive PMT detector modules and a dual layer phoswich detector technology provide high quality pre-clinical images throughout the field of view.
  • a CT scan was obtained first (with a voltage of 40 kV and a beam current of 140 ⁇ ) followed by a 40 minute list-mode PET acquisition (with a 250-700 keV energy window).
  • the scanner had a ring diameter of 1 1.8 cm and a 4.8 cm axial field of view (FOV).
  • 3-Dimensional (3D) sinograms were converted into
  • Co-registration involves non-linear warping of the data to match the template image using the Brain Norm II algorithm from Pmod version 3.0.
  • CT data have a higher resolution and higher noise levels than the atlas image and are in Hounsfield units rather than the relative scale used by the atlas, the images were smoothed using a 3D Gaussian filter with FWHM of 0.5 mm in all directions.
  • the dynamic range of the CT images was also adjusted to match that of the atlas. Finally, if any truncation artefacts were visible, these were removed from the CT images.
  • a 3D region of interest that fully encompassed the head of the mouse was drawn on the images by hand and all voxels outside this region were set to zero.
  • the rigid and non-linear warping transformations calculated for the CT images were also applied to register images to the Digimouse template.
  • voxel values in PET images are influenced by a number of factors (e.g., injected dose, weight of the animal, pharmacokinetics of the FDG), normalisation of the images was required.
  • data was normalized either via whole brain, or relative to a pre-selected brain region not affected by the disorder (e.g., cerebellum) as a reference region.
  • ⁇ -amyloid peptides are the main protein components of neuritic plaques, one of the most important pathological characteristics of Alzheimer's disease (AD).
  • AD Alzheimer's disease
  • the APP/PSEN transgenic mouse is a well-characterised Alzheimer's disease (AD) model and has a heavy amyloid plaque load.
  • fluorobarbiturates such as (6) can be used to identify and image amyloid plaque and AD.
  • Alzheimer's disease Brain Res. Rev., Vol. 41 , pp. 44-56.
  • Schizophrenia Schizophrenia Bulletin, Vol. 33, pp. 1 100-1 1 19.

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Abstract

The present invention relates generally to the field of diagnostic methods. More specifically, the present invention pertains to certain 18F-labelled barbiturate compounds of the following formula (collectively referred to herein as "18F-fluorinated barbiturate compounds" and "18FBAR compounds") that bind to metals, for example, metals associated with protein aggregates, and as such are useful as imaging agents for positron emission imaging (e.g., positron emission tomography (PET) imaging) used in the diagnosis and monitoring of conditions involving these aggregates, including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). These compounds also bind strongly to GABAA receptors and hence are also useful as imaging agents for positron emission tomography (PET) imaging used in the diagnosis, monitoring and study of diseases involving dis-regulation of these receptors, including epilepsy, schizophrenia, and mood disorders (e.g., anxiety).

Description

18 F-LABELLED BARBITURATE COMPOUNDS FOR USE AS
POSITRON EMISSION IMAGING AGENTS
RELATED APPLICATION
This application is related to United Kingdom patent application number 1 1 15937.3 filed 14 September 201 1 , the contents of which are incorporated herein by reference in their entirety.
TECHNICAL FIELD
The present invention relates generally to the field of diagnostic methods. More specifically, the present invention pertains to certain 18F-labelled barbiturate compounds (collectively referred to herein as "18F-fluorinated barbiturate compounds" and "18FBAR compounds") that bind to metals, for example, metals associated with protein aggregates, and as such are useful as imaging agents for positron emission imaging (e.g., positron emission tomography (PET) imaging) used in the diagnosis and monitoring of conditions involving these metals and/or aggregates, including Alzheimer's disease (AD),
Parkinson's disease (PD), Huntington's disease (HD), etc. These compounds also bind strongly to GABAA receptors and hence are also useful as imaging agents for positron emission imaging (e.g., positron emission tomography (PET) imaging) used in the diagnosis, monitoring and study of diseases involving dis-regulation of these receptors, including epilepsy, schizophrenia, and mood disorders (e.g., anxiety). BACKGROUND
A number of patents and publications are cited herein in order to describe and disclose the invention more fully and the state of the art to which the invention pertains. Each of these references is incorporated herein by reference in its entirety into the present disclosure, to the same extent as if each individual reference was specifically and individually indicated to be incorporated by reference.
Throughout this specification, including the claims that follow, unless the context requires otherwise, the word "comprise," and variations such as "comprises" and "comprising," will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a pharmaceutical carrier" includes mixtures of two or more such carriers, and the like. Ranges are often expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment.
This disclosure includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Barbiturates Barbiturates have found extensive clinical use in the past as hypnotics, anxiolytics and sedatives. Safety issues, such as physical dependence, drug-drug interactions, respiratory depression and a low therapeutic index have restricted usage in recent years. However, several barbiturates remain in clinical use today, including: phenobarbital, as an anti-convulsant for the control of epilepsy; thiopental, as a fast-acting but transient anaesthetic; and pentobarbital, as a rarely-used anxiolytic or sedative. One of the features common to many barbiturates is rapid passage through the blood-brain barrier, which gives a rapid pharmacological effect.
In terms of chemical structure, barbiturates are derivatives of barbituric acid (also referred to as pyrimidine-2,4,6(1 H,3H,5H)-tr\one) (shown below).
Figure imgf000003_0001
number of barbiturates (shown below) are well known.
Figure imgf000003_0002
Figure imgf000004_0001
Figure imgf000005_0001
Figure imgf000006_0001
Figure imgf000007_0001
It appears that di-substitution at the 5-position is required for central nervous system (CNS) activity (see, e.g., Adamczyk et al., 1997). Replacement of the oxygen at the 2-position with sulfur, or alkylation of the N-1 nitrogen also gives highly potent drugs which very rapidly cross the blood-brain barrier (see, e.g., Nogrady, 2005). Active barbiturates may have aryl, alkyl or cycloalkyl substitutents at the 5-position, as in, for example, phenobarbital, pentobarbital and hexobarbital, respectively.
In general, the term "barbiturate" is recognized to encompass derivatives of barbituric acid and salts thereof, in which: one or both of the ring nitrogen atoms has a substituent (e.g., an alkyl group) (e.g., as in narconumal); the 2-oxo group is replaced with a 2-thio group (e.g., as in thiopental sodium); one substituent, or more often two substituents, are present at the 5-position; or a combination thereof.
Barbiturates as Targeting Agents
In spite of drawbacks with their therapeutic use, barbiturates have a number of properties which make them ideal as targeting agents for use in the diagnosis and monitoring of a number of neurological disorders. The primary attributes of barbiturates upon which this application is based are: the strong binding of barbiturates to metals, a number of which are found in elevated concentrations in neurodegenerative disorders, including
Alzheimer's disease (AD); the capacity of barbiturates to form very stable supramolecular structures with polar molecules such as melamine, through hydrogen bonded recognition patterns, which could lead to the formation of stable aggregates with the peptides and proteins involved in neurological disorders, including beta-amyloid peptide (see, e.g., Yagai, 2006); the strong binding of barbiturates to the GABAA receptor, which is dis-regulated in a number of neurological disorders, including epilepsy, anxiety and schizophrenia.
Fluorine (F) exists as one of six isotopes: 17F, 18F, 19F, 20F, 21F, and 22F. The natural abundance of 19F is 100%. The radioisotope 18F can be prepared using conventional means (e.g., by bombarding 180-enriched water with high energy protons) and has a half-life of about 1 10 minutes. When 18F decays, it generates 180 and positrons (β+).
Labelling of barbiturates with 18F permits their use as positron emission tomography (PET) imaging agents. PET is a powerful non-invasive molecular imaging technique. It is used to study and visualise in vivo biological disorders at the molecular level, by detection of positron-emitting radiotracers, before anatomical changes become apparent.
Therefore, PET may be used for early detection and monitoring of diseases, as well as investigating the efficacy of drugs. The information that PET provides at molecular level about biochemical processes (functional information) is not available from other conventional imaging techniques such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). On the other hand, these imaging modalities provide a detailed picture of the body's internal anatomy (anatomical information). The combination of PET with one of these imaging tools allows the matching of functional and anatomical information. For example, the combined PET/CT technique provides complete information both on disease location and metabolism. As a result, small lesions such as tau tangles and Αβ plaques, which may not show anatomical changes in size or shape, could be detected with PET (high sensitivity) and then exactly located with CT (high resolution). Protein Aggregates and Elevated Metal Concentrations
There is a growing body of evidence that elevated concentrations of a number of metals are seen in diseases involving protein aggregates, which are a key hallmark of a number of disorders such as Alzheimer's disease (amyloid plaques and neurofibrillary tangles), Parkinson's disease (synuclein), scrapie and Creutzfeldt-Jakob disease (prions) (see, e.g., Piatt, 2008). For example, levels of copper, zinc and iron are increased 3- to 5-fold in certain regions of the brain most affected by AD pathology (see, e.g., Adlard and Bush, 2006; White and Bush, 2008). These metals may also play a key role in the development of the disease, both by seeding the formation of protein aggregates and, particularly in the case of copper, by the generation of reactive oxygen and nitrogen species.
These aggregates have a high affinity for metals such as copper, zinc, iron and aluminium, that is, these aggregates act as sinks and accumulate metals accordingly (see, e.g., White and Bush 2008). Beta-amyloid (Αβ), as commonly found in AD, has strong chelating properties for Cu(ll) and Zn(ll) (see, e.g., Domingo, 2006; Adlard and Bush, 2006).
Copper has an exceptionally high affinity for β-amyloid and binding coefficients of
« 0.1 nM have been reported (see, e.g., Cuajungco and Faget, 2003; White and Bush, 2008), binding primarily to the to histidine residues at two separate sites. In vitro studies demonstrate that β-amyloid will aggregate at concentrations of copper well below those generally found in the brain (see, e.g., White and Bush, 2008). Neurofibrillary tangles, also strongly associated with PD pathology, have also been shown to bind copper (see, e.g., Cuajungco and Faget, 2003); their formation may be associated with the redox activity of Cu(ll) associated with β-amyloid plaques.
Abnormally high zinc concentrations have also been found in the areas of the brain most affected by AD pathology, including the hypocampus, cortex and cortical vasculature (see, e.g., Cuajungco and Faget, 2003) and are associated with amyloid plaques. Zinc has a somewhat lower affinity for β-amyloid than copper, with KD values of 100 nM reported (see, e.g., Cuajungco and Faget, 2003); however zinc is an essential element and is therefore normally present at higher concentrations than copper and therefore is likely to be an equally important disease marker. Recently, pre-clinical PET/CT studies with the metal chelator [18F]2-fluoroquinolin-8-ol demonstrated that Zn(ll) / β-amyloid aggregates can be imaged in vivo and used to identify β-amyloid mice models (see, e.g., Vasdev, 2012). Zinc is redox inactive and thus is not directly responsible for the generation of reactive oxygen species; in fact, there is some conflicting evidence to suggest that zinc may be neuroprotective under certain circumstances.
Highly elevated levels of iron are also seen both in β-amyloid plaques and in
neurofibrillary tangles (see, e.g., White and Bush, 2008) and again correlate with areas of the brain most affected by AD pathology (see, e.g., Lei, 2012). Other metals shown to have elevated levels in amyloid plaques include aluminium, chromium and nickel.
High localised concentrations of these metals can be used for early diagnosis and effective monitoring of therapy. Early stage dementia is often unrecognised or misdiagnosed; pre-symptomatic diagnosis would facilitate early intervention and thus improve the chances of successful therapy, either preventing development of full-blown disease or delaying progression to the debilitating symptomatic stages. Furthermore, it has also been suggested that these metals may play an important role in seeding the formation of these aggregates and that their removal may be of therapeutic benefit (see, e.g., Domingo, 2006); this hypothesis is supported by the current clinical development of clioquinol, an antibiotic / anti-amoebic agent which strongly binds Cu(ll) and Zn(ll) (see, e.g., Domingo, 2006) as a treatment for AD (see, e.g., Mancino et al., 2009). Phase II studies on clioquinol showed a 49% decrease in brain Αβ deposition (see, e.g., Domingo, 2006). Removal of these metals may have other beneficial effects, including reduction in oxidative stress caused by redox-active transition metals such as copper.
Dis-regulation or accumulation of metals has also been shown to play a role in other neurodegenerative disorders, including amyotrophic lateral sclerosis (see, e.g., Piatt, 2006), particularly in the case of iron, and Huntington's disease (see, e.g., Yokel, 2006; Bush and White, 2008). Elevated levels of iron have also been found in the affected region (the substantia nigra) of PD patients and this is often regarded as a disease in which occupational exposure to a number of metals is a major contributing factor (see, e.g., Yokel 2006).
Barbiturates and Metal Binding
Barbiturates have been shown to bind strongly to divalent metals, including Zn(ll) (see, e.g., Tochowicz et al., 2007; Breyholz et al., 2005; Wang, et al 201 1 ; Sheppeck et al., 2007a; Soong-Hoon Kim et al., 2005). This attribute has been widely used to develop drugs targeted against zinc-containing endopeptidases and a number of highly potent matrix metalloprotease inhibitors, with IC50 values of < 10 nM, have been reported. Matrix metalloproteases are over-expressed in certain metastatic tumours, in osteoarthritis and in rheumatoid arthritis; thus barbiturate derivatives may show therapeutic utility in the treatment of these diseases, and probes based on barbiturates may be useful in diagnosing and imaging disease progression. Barbiturates have also been used as zinc-binding groups to target drugs to a range of other enzymes, including TNFa converting enzyme (TACE) inhibitors (e.g., Sheppeck, et al 2007b; Duan,et al., 2007); TNFa has been shown to play a pivotal role in a range of inflammatory disorders and thus drugs which prevent its release are expected to show clinical utility in the treatment of diseases such as rheumatoid arthritis and inflammatory bowel disease.
Furthermore, barbiturate derivatives have also been shown to bind to a number of other divalent cations, for example, those found in the active site of methionine
aminopeptidase-1 , including cobalt (see, e.g., Manas et al., 2008).
Furthermore, barbiturates form stable and soluble calcium salts, for example,
cyclobarbital calcium (CAS 143-76-0) and pentobarbital calcium (CAS 7563-42-0).
Barbiturates also form stable salts with cobalt(ll), nickel(ll) and copper(ll); the copper(ll) salts have been shown to retain anti-convulsant activity (see, e.g., Sevilla et al., 1992; Pezeshk, 1983).
Barbiturates and the GABAA receptor and Epilepsy
Barbiturates bind strongly to the GABAA-receptor (see, e.g., Nogrady, 2005). GABA is the most widespread inhibitory neurotransmitter in the brain. Barbiturates have a general depressant action on the central nervous system by enhancing the action of GABA on the GABAA-receptor, a ligand-gated chloride channel (see, e.g., Olsen, 1986). A number of drugs including phenobarbital, benzodiazepines, topiramate, vigabatrin and tiagabine are used for the treatment of epilepsy and act by enhancing the activation of GABAA- receptors, either directly or by inhibition of GABA metabolism or re-uptake.
Roles for the GABA-ergic System in Other Disease States
A prominent role for the GABA-ergic system in schizophrenia has been postulated (see, e.g., Benes, 1996; Keverne, 1999; Schiffer et al., 2001 ). Significantly, a defect in the GABA-ergic system in the pre-frontal cortex has been found in patients with
schizophrenia (see, e.g., Tamminga, 2007) and this is assumed to be involved in the cognitive symptoms of schizophrenia. Levels of the GABA-producing enzyme glutamic acid decarboxylase (GAD67) and GABA are both decreased, whilst the a2 subunit of GABAA receptor is selectively increased (see, e.g., Tamminga, 2007; Gray and Wroth, 2007). Chandelier cells are GABA-ergic neurones which play a prominent role in modulating neuronal activity in regions featuring excitatory impulses, especially on pyramidal cells which are affected in schizophrenia. A 45% reduction in the density of the arrays made up of these regulatory chandelier cells has been shown in the schizophrenic brain (see, e.g., Keverne, 1999). The dopamine D4 receptor is recognized to be of particular importance in schizophrenia, as certain effective therapeutic agents (e.g., clozapine) act upon it. As D4 receptors are mainly located on chandelier neurones and pyramidal cells, it is highly likely that the GABA-ergic system plays a major role in the regulation of D4 receptors and that the loss of these inhibitory GABA-ergic neurones, and the stability that they provide, plays a major role in the pathology of schizophrenia. Likewise, it has been reported that both uptake and release of GABA is reduced in the schizophrenic brain (see, e.g., Keverne, 1999). Underactivity in the GABA-ergic system has also been implicated as playing a major role in Huntington's disease (see, e.g., Nogrady, 2005).
18F Barbiturates Kopka et al., 2004, report the synthesis of a number of 18F-labelled 5-piperizino- barbiturates for use in PET imaging of a range of diseases, including atherosclerosis. However, no biological or imaging data is given for these compounds. Furthermore, the compounds exemplified (shown below) are quite dissimilar in structure to the barbiturates that are in clinical use and thus are unlikely to have the same favourable pharmacokinetic properties (e.g., initial brain penetration followed by rapid distribution).
Figure imgf000012_0001
Kopka et al., 2004
Compound 10
Example 1 1 at pages 46-47
19
F Barbiturates
A number of 19F-fluorinated barbiturates have been described.
Bruce and Huber, 1953, describe the synthesis of a number of 5-alkyl-5-(oo-fluoroalkyl) derivatives of barbituric acid (shown below) and reports that these show sedative and hypnotic activity, but are not as potent or as useful as the parent compounds. However, the authors note that the fluorine exerts its own characteristics on the activity of the barbiturates containing it and that this is quite different to analogues containing other halogens.
Figure imgf000013_0001
O'Neill and Pattison, 1957, report the synthesis and testing of two ω-fluoroalkylbarbituric acids (shown below) for testing as depressants of the central nervous system and record low toxicity (LD50 > 100 mg/kg) for the 4-fluorobutyl derivative.
Figure imgf000014_0001
Muller, 1986, reports the synthesis of trifluoromethyl barbiturate analogues of barbital and amobarbital (shown below), but does not report any biological data.
Figure imgf000014_0002
However, none of these compounds is labelled with 18F. 19F is not a positron emitter, and the above compounds cannot be used as PET imaging agents. Furthermore, these teachings do not describe binding of the barbiturates to metals, protein aggregates or to GABAA receptors, and thus do not suggest the use of 18F-labelled barbiturates (as described herein) as imaging agents for neurological disorders.
18F Radiotracers for Imaging of Alzheimer's Disease
A number of 18F radio-tracers for the PET imaging of Alzheimer's disease (AD) have been described and have entered clinical development, including florbetapir (Eli Lilly), florbetaben (Bayer) and flutemetamol (GE Healthcare) (shown below).
Florbetapir
Florbetaben Flutemetamol
Figure imgf000015_0001
However, none of these compounds are barbiturates or barbiturate analogues.
Furthermore, these compounds do not bind to metals or to the GABAA receptor (their mode of binding is via intercalation between the polypeptide sheets).
18F Tracers for Imaging of Cancer
Certain 18F-labelled compounds have also been developed for a number of other indications, most commonly targeting matrix metalloproteases (MMPs) and for tumour imaging. Furumoto et al., 2003a and Furumoto et al., 2003b describe the following compounds:
Figure imgf000015_0002
However, none of these compounds are barbiturates or barbiturate analogues. SUMMARY OF THE INVENTION
One aspect of the invention is an 18F-fluorinated barbiturate compound
("18FBAR compound"), as described herein.
Another aspect of the invention is a composition (e.g., a pharmaceutical composition) comprising an 18FBAR compound as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient. Another aspect of the invention is a method of preparing a composition (e.g., a pharmaceutical composition) comprising the step of admixing an 18FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
Another aspect of the invention is an 18FBAR compound as described herein for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
Another aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
Another aspect of the invention is a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject which employs an 18FBAR compound as described herein as an imaging agent.
Another aspect of the invention is an 18FBAR compound as described herein for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject). Another aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
Another aspect of the invention is a method of diagnosis or prognosis of a disease or disorder in a subject, which employs an 18FBAR compound as described herein.
Another aspect of the invention is an 18FBAR compound as described herein for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy). Another aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy). Another aspect of the invention is a method of therapeutic monitoring of a therapy for a disease or disorder in a subject undergoing said therapy, which employs an 18FBAR compound as described herein.
In one embodiment, the disease or disorder is a disease or disorder involving deposition of protein aggregates.
In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals.
In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates. In one embodiment, the disease or disorder is Alzheimer's disease (AD).
In one embodiment, the disease or disorder is Parkinson's disease (PD).
In one embodiment, the disease or disorder is Huntington's disease (HD).
In one embodiment, the disease or disorder is a disease or disorder involving
dis-regulation of a GABAA receptor.
In one embodiment, the disease or disorder is a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors.
In one embodiment, the disease or disorder is epilepsy, schizophrenia, or a mood disorder (e.g., anxiety). In one embodiment, the disease or disorder is metal overdose or metal poisoning.
In one embodiment, the disease or disorder is a disease or disorder associated with metal-induced leakiness of the blood-brain barrier. Another aspect of the present invention is an 18FBAR compound obtainable by a method of synthesis as described herein, or a method comprising a method of synthesis as described herein. Another aspect of the present invention is an 18FBAR compound obtained by a method of synthesis as described herein, or a method comprising a method of synthesis as described herein.
Another aspect of the present invention is a novel intermediate, as described herein, which is suitable for use in the methods of synthesis described herein.
Another aspect of the present invention is the use of such novel intermediates, as described herein, in the methods of synthesis described herein. As will be appreciated by one of skill in the art, features and preferred embodiments of one aspect of the invention will also pertain to other aspects of the invention.
DETAI LED DESCRI PTION OF THE I NVENTION
Compounds One aspect of the present invention relates to certain compounds which are related to barbituric acid (also referred to as pyrimidine-2,4,6(1 H,3H,5H)-tr\one):
Figure imgf000019_0001
All of the compounds of the present invention have a fluorinated substituent at the 5-position (denoted herein as -A4), wherein at least one of the fluorine atoms of the fluorinated substituent is the radioactive isotope 18F.
Thus, one aspect of the present invention is a compound of the following formula, or a pharmaceutically acceptable salt, hydrate, or solvate thereof, wherein =X, -A1, -A2, -A3, and -A4 are as defined herein (for convenience, collectively referred to herein as "18F-fluorinated barbiturate compounds" and "18FBAR compounds"):
Figure imgf000019_0002
Some embodiments of the invention include the following:
(1 ) A compound of the following formula:
Figure imgf000019_0003
or a pharmaceutically acceptable salt or solvate thereof;
wherein:
=X is independently =0 or =S;
-A1 is independently -H, -A1A, or -A1 B; -A1A is saturated aliphatic C1-4alkyl;
-A1B is saturated C3-6cycloalkyl;
-A2 is independently -H, -A2A, or -A2B;
-A2A is saturated aliphatic C1-4alkyl;
-A2B is saturated C3-6cycloalkyl;
-A3 is independently -A3A, -A3B, -L3-A3B, -A3C, -L3-A3C, -A3D, -L3-A3D, -A3E, or -L3-A3E; -A3A is independently -A3A1, -A3A2, or -A3A3;
-A3A1 is saturated aliphatic Ci_i0alkyl, and is optionally substituted, for example, with one or more groups -Rx;
-A3A2 is aliphatic C2-ioalkenyl, and is optionally substituted, for example, with one or more groups -Rx;
-A3A3 is aliphatic C2-ioalkynyl, and is optionally substituted, for example, with one or more groups -Rx; each -A3B is independently -A3B1 or -A3B2;
each -A3B1 is saturated C3-7cycloalkyl, and is optionally substituted, for example, with one or more groups -RY;
each -A3B2 is C4-7cycloalkenyl, and is optionally substituted, for example, with one or more groups -RY; each -A3C phenyl, and is optionally substituted, for example, with one or more groups -RY; each -A3D is C5-6heteroaryl, and is optionally substituted, for example, with one or more groups -RY; each -A3E is non-aromatic C4-7heterocyclyl, and is optionally substituted, for example, with one or more groups -RY; each -L3- is saturated aliphatic Ci-4alkylene; -A4 is independently -A4A, -A4B, -L4-A4B, -A4C, -L4-A4C, -A4D, or -L4-A4D;
-A4A is independently -A4A1, -A4A2, or -A4A3;
-A4A1 is saturated aliphatic C1-10alkyl substituted with one or more groups -RFA, and optionally is further substituted, for example, with one or more groups -Rx;
-A4A2 is aliphatic C2-ioalkenyl substituted with one or more groups -RFA, and optionally is further substituted, for example, with one or more groups -Rx; -A is aliphatic C2-ioalkynyl substituted with one or more groups -R optionally is further substituted, for example, with one or more groups -Rx; each -A is independently -A4m or -A ;
each -A4B1 is saturated C3-7cycloalkyl substituted with one or more groups -RFB and optionally is further substituted, for example, with one or more groups -RY;
each -A4B2 is C4-7cycloalkenyl substituted with one or more groups -RFB, and optionally is further substituted, for example, with one or more groups -RY; each -A4C is phenyl substituted with one or more groups -RFC, and optionally is further substituted, for example, with one or more groups -RY; each -A is C5-6heteroaryl substituted with one or more groups -R
optionally is further substituted, for example, with one or more groups -RY; each -L4- is saturated aliphatic Ci-4alkylene; each -R is -R ,
each -RFB is independently -RF1 or -Rf
each -RFC is independently -RF1 or -R1
each -RFD is independently -RF1 or -R1 each -RF1 is an 18F atom;
each -RF2 is a saturated aliphatic C1-6alkyl group substituted with one or more 18F atoms; each -R , if present, is independently selected from:
-F, -CI, -Br, -I, -CF3, phenyl, -OH, -ORs, -OCF3, -NH2, -NHRS, -NRS 2, pyrrolidine piperidino, morpholino, piperazino, N-(Ci-4alkyl)-piperazino, -NHC(=0)Rs, -NRsC(=0)Rs, -C(=0)Rs, -C(=0)OH, -C(=0)ORs, -C(=0)NH2, -C(=0)NHRs, -C(=0)NRs 2,
-C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino,
-C(=0)-{N-(C1-4alkyl)-piperazino}-, -SRS, -S(=0)Rs, -S(=0)2Rs, -S(=0)2NH2,
Figure imgf000021_0001
-S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino, -S(=0)2-piperazino, -S(=0)2-{N-(C1-4alkyl)-piperazino}-, -NHS(=0)2Rs, and -NRsS(=0)2Rs; wherein each -Rs is independently saturated aliphatic Ci-6alkyl, phenyl, or
-CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups
independently selected from: -F, -CI, -Br, -I, -Rss, -CF3, -OH, -ORss, -OCF3, -NH2,
-NHRSS, and -NRSS 2, wherein each -Rss is saturated aliphatic d^alkyl; and each -RY, if present, is independently selected from:
-F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidine piperidino, morpholino, piperazino, N-(C1-4alkyl)-piperazino, -NHC(=0)RT, -NRTC(=0)RT, -C(=0)RT, -C(=0)OH, -C(=0)ORT, -C(=0)NH2, -C(=0)NHRT, -C(=0)NRT 2, -C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino,
-C(=0)-{N-(Ci.4alkyl)-piperazino}-, -SRT, -S(=0)RT, -S(=0)2RT, -S(=0)2NH2, -S(=0)2NHRT, -S(=0)2NRT 2, -S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino,
-S(=0)2-piperazino, -S(=0)2-{N-(Ci_4alkyl)-piperazino}-, -NHS(=0)2RT, and -NRTS(=0)2RT; wherein each -RT is independently saturated aliphatic Ci-6alkyl, phenyl, or
-CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups
independently selected from: -F, -CI, -Br, -I, -RTT, -CF3, -OH, -ORTT, -OCF3, -N H2, -NHRTT, or -NRTT 2, wherein each -RTT is saturated aliphatic Ci-4alkyl. For the avoidance of doubt:
A reference to an "18F atom" is intended to indicate that, in a sample of the compound, said atom is present as 18F with an abundance of at least 25% (on a molar basis) relative to 180 (the isotope formed upon radioactive decay of 18F). Preferably, said atom is present with an abundance of at least 50% (on a molar basis) related to 180. More preferably, said atom is present with an abundance of at least 75% (on a molar basis) related to 180. More preferably, said atom is present with an abundance of at least 85% (on a molar basis) related to 180. More preferably, said atom is present with an abundance of at least 90% (on a molar basis) related to 180. More preferably, said atom is present with an abundance of at least 95% (on a molar basis) related to 180.
The term "aliphatic" refers to linear and branched groups. For example, the term
"aliphatic alkyl" refers to linear and branched alkyl groups, but not alicyclic alkyl
(e.g., cycloalkyl) groups. For example, -nBu is an example of a linear C4alkyl group, and -iBu is an example of a branched C4alkyl group; in this way, both -nBu and -iBu are examples are aliphatic C4alkyl groups.
The term "alkyl" (e.g., Ci-i0alkyl) refers to groups that have no carbon-carbon double bonds and no carbon-carbon triple bonds. Ethyl (-CH2CH3) is an example of a C2alkyl group.
The term "alkenyl" (e.g., C2-i0alkenyl) refers to groups that have at least one carbon- carbon double bond, but no carbon-carbon triple bonds. Allyl (-CH2-CH=CH) is an example of a C3alkenyl group. The term "alkynyl" (e.g., C2-ioalkynyl) refers to groups that have at least one carbon- carbon triple bond. Propargyl (-CH2-C≡CH) is an example of a C3alkynyl group.
The term "cycloalkyl" (e.g., C3-7cycloalkyl) refers to groups that have no carbon-carbon double bonds, and no carbon-carbon triple bonds. Cyclohexyl is an example of a C6cycloalkyl group.
The term "cycloalkenyl" (e.g., C4-7cycloalkenyl) refers groups that have at least one carbon-carbon double bond, but no carbon-carbon triple bonds. Cyclohexenyl is an example of a C6cycloalkenyl group.
The index "Cx-y" in terms such as "C5-ioheteroaryl", "C3-7heterocyclic ring",
"C3-7heterocyclyl", and the like, refers to the number of ring atoms, which may be carbon atoms or heteroatoms (e.g., N, O, S). For example, pyridyl is an example of a
C6heteroaryl group, and piperidino is an example of a C6heterocyclyl group.
The term "heteroaryl" refers to a group that is attached to the rest of the molecule by an atom that is part of an aromatic ring, wherein the aromatic ring is part of an aromatic ring system, and the aromatic ring system has one or more heteroatoms (e.g., N, O, S). For example, pyridyl is an example of a C6heteroaryl group, and quinolyl is an example of a Cioheteroaryl group.
The term "heterocyclyl" refers to a group that is attached to the rest of the molecule by a ring atom that is not part of an aromatic ring (i.e., the ring is partially or fully saturated), and the ring contains one or more heteroatoms (e.g., N, O, S). For example, piperidino is an example of a C6heterocyclyl group.
Depending upon the values of -A3 and -A4, the carbon atom to which they are attached may be chiral, and if so, may independently be in the (R) or (S) configuration. Unless otherwise indicated, it is intended that both configurations are encompassed. In one embodiment, the configuration is (S). In one embodiment, the configuration is (R).
Where a carbon-carbon double bond is shown, and unless otherwise indicated, it is intended that all configurations about the double bond are encompassed, for example, both cis- and trans-, and both E- and Z-.
The Group =X
(2) A compound according to (1 ), wherein =X is =0.
(3) A compound according to (1 ), wherein =X is =S. The Group -A1
(4) A compound according to any one of (1 ) to (3), wherein -A1 is -H or -A1A.
(5) A compound according to any one of (1 ) to (3), wherein -A1 is -H.
(6) A compound according to any one of (1 ) to (3), wherein -A1 is -A1A. (7) A compound according to any one of (1 ) to (3), wherein -A1 is -A1B.
The Group -A2
(8) A compound according to any one of (1 ) to (7), wherein -A2 is -H or -A' 2A
(9) A compound according to any one of (1 ) to (7), wherein -A2 is -H.
(10) A compound according to any one of (1 ) to (7), wherein -A2 is -A2A. (1 1 ) A compound according to any one of (1 ) to (7), wherein -A2 is -A2B.
The Group -A1A
(12) A compound according to any one of (1 ) to (1 1 ), wherein -A1A, if present, is independently -Me, -Et, -nPr, or -iPr.
(13) A compound according to any one of (1 ) to (1 1 ), wherein -A1A, if present, is independently -Me or -Et. (14) A compound according to any one of (1 ) to (1 1 ), wherein -A1A, if present, is -Me.
(15) A compound according to any one of (1 ) to (1 1 ), wherein -A1A, if present, is -Et.
The Group -A2A
(16) A compound according to any one of (1 ) to (15), wherein -A2A, if present, is independently -Me, -Et, -nPr, or -iPr.
(17) A compound according to any one of (1 ) to (15), wherein -A2A, if present, is independently -Me or -Et. (18) A compound according to any one of (1 ) to (15), wherein -A , if present, is -Me.
(19) A compound according to any one of (1 ) to (15), wherein -A , if present, is -Et. The Group -A1
(20) A compound according to any one of (1 ) to (19), wherein -A1B, if present, is independently cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl. (21 ) A compound according to any one of (1 ) to (19), wherein -A1B, if present, is independently cyclopropyl or cyclobutyl.
(22) A compound according to any one of (1 ) to (19), wherein -A1B, if present, is cyclopropyl.
The Group -A2B
(23) A compound according to any one of (1 ) to (22), wherein -A2B, if present, is independently cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl.
(24) A compound according to any one of (1 ) to (22), wherein -A2B, if present, is independently cyclopropyl or cyclobutyl.
(25) A compound according to any one of (1 ) to (22), wherein -A2B, if present, is cyclopropyl.
The Group -A3
(26) A compound according to any one of (1 ) to (25), wherein -A3 is independently -A' 3A -A3B, -L3-A3B, -A3C, -L3-A3C, -A3D, -L3-A3D, or -A
(27) A compound according to any one of (1 ) to (25), wherein -A3 is independently -A: 3A -A3B, -L3-A3B, -A3C, -L3-A3C, -A3D, or -L3-A3D. (28) A compound according to any one of (1 ) to (25), wherein -A3 is independently -A'
_A3B _A3C _|_3_A3C _A3D Qf. _|_3_A3D
(29) A compound according to any one of (1 ) to (25), wherein -A3 is independently -A: 3A
-A3B, -A3C, -L3-A3C, or -A3D. (30) A compound according to any one of to (25 wherein -A3 is independently -A: 3A -A3B, -A3C, or -A3D
(31 ) A compound according to any one of to (25 wherein -A is independently -A3A, -A3B, or -A3C.
(32) A compound according to any one of to (25 wherein -A3 is -A'
(33) A compound according to any one of to (25 wherein -A3 is -A'
(34) A compound according to any one of to (25 wherein -A3 is -L3-A;
(35) A compound according to any one of to (25 wherein -A3 is -A'
(36) A compound according to any one of to (25 wherein -A3 is -L3-A;
(37) A compound according to any one of to (25 wherein -A3 is -A'
(38) A compound according to any one of to (25 wherein -A3 is -L3-A;
(39) A compound according to any one of to (25 wherein -A3 is -A'
(40) A compound according to any one of to (25 wherein -A3 is -L3-A;
The Group -A 3A
(41 ) A compound according to any one of to (40 wherein -A , if present, is -A'
(42) A compound according to any one of 3A2 to (40 wherein -A , if present, is -A'
(43) A compound according to any one of to (40 wherein -A3A, if present, is -A3A3. The Group -A3A1
(44) A compound according to any one of to (43 wherein -A , if present, is saturated aliphatic C1-10alkyl.
(45) A compound according to any one of (1 ) to (43 wherein -A , if present, is saturated aliphatic Ci-8alkyl, and is optionally substi uted with one or more groups (46) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is saturated aliphatic Ci-8alkyl.
(47) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is saturated aliphatic C1-6alkyl, and is optionally substituted with one or more groups -Rx.
(48) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is saturated aliphatic Ci-6alkyl. (49) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is independently -Me, -Et, -nPr, -iPr, -nBu, -iBu, -sBu, -tBu, -(CH2)4CH3,
-CH(CH3)(CH2)2CH3, -(CH2)2CH(CH3)2, -(CH2)5CH3, -CH(CH3)(CH2)3CH3, or
-(CH2)3CH(CH3)2. (50) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is -Me.
(51 ) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is -Et.
(52) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is independently -nPr or -iPr.
(53) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is independently -nBu, -iBu, -sBu, or -tBu. (54) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is saturated aliphatic C5alkyl.
(55) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is independently -(CH2)4CH3, -CH(CH3)(CH2)2CH3, or -(CH2)2CH(CH3)2.
(56) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is saturated aliphatic C6alkyl.
(57) A compound according to any one of (1 ) to (43), wherein -A3A1, if present, is independently -(CH2)5CH3, -CH(CH3)(CH2)3CH3, or -(CH2)3CH(CH3)2.
The Group -A3A2
(58) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C2-i0alkenyl. (59) A compound according to any one of (1 ) to (57), wherein -A , if present, is aliphatic C3-i0alkenyl, and is optionally substituted with one or more groups -Rx.
(60) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C3-10alkenyl.
(61 ) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C2-8alkenyl, and is optionally substituted with one or more groups -Rx. (62) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C2-8alkenyl.
(63) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C3-8alkenyl, and is optionally substituted with one or more groups -Rx.
(64) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C3-8alkenyl.
(65) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C2-6alkenyl, and is optionally substituted with one or more groups -Rx.
(66) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C2-6alkenyl. (67) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C3-6alkenyl, and is optionally substituted with one or more groups -Rx.
(68) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is aliphatic C3-6alkenyl.
(69) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is independently -CH2-CH=CH2, -CH2-C(Br)=CH2, or -C(CH3)=CH-CH2CH3.
(70) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is
-CH2-CH=CH2.
(71 ) A compound according to any one of (1 ) to (57), wherein -A3A2, if present, is
-CH2-C(Br)=CH2. (72) A compound according to any one of (1 ) to (57), wherein -A , if present, is
-C(CH3)=CH-CH2CH3. The Group -A 3A3
(73) A compound according to any one of 1 ) to (72), wherein -A i 3A3 , if present, is aliphatic C2-ioalkynyl.
(74) A compound according to any one of i 1 ) to (72), wherein -A , if present, is aliphatic C3-i0alkynyl, and is optionally substituted with one or more groups (75) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C3-i0alkynyl.
(76) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C2-8alkynyl, and is optionally substituted wi h one or more groups -Rx.
(77) A compound according to any one of 1 ) to (72), wherein -A3A3, if present, is aliphatic C2-8alkynyl.
(78) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C3-8alkynyl, and is optionally substituted wi h one or more groups -Rx.
(79) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C3-8alkynyl. (80) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C2-6alkynyl, and is optionally substituted wi h one or more groups -Rx.
(81 ) A compound according to any one of 1 ) to (72), wherein -A3A3, if present, is aliphatic C2-6alkynyl.
(82) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C3-6alkynyl, and is optionally substituted wi h one or more groups -Rx.
(83) A compound according to any one of 1 ) to (72), wherein -A , if present, is aliphatic C3-6alkynyl.
(84) A compound according to any one of 1 ) to (72), wherein -A , if present, is
-CH(CH3)-C≡C-CH2CH3. The Group -A'
(85) A compound according to any one of (1 ) to (84), wherein each -A , if present, is -A3B1.
(86) A compound according to any one of (1 ) to (84), wherein each -A , if present, is
_A3B2
The Group -A3B1
(87) A compound according to any one of (1 ) to (86), wherein each -Ajm, if present, is saturated C3-7cycloalkyl.
(88) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated C4-6cycloalkyl, and is optionally substituted with one or more groups -RY.
(89) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated C4-6cycloalkyl. (90) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated C5-6cycloalkyl, and is optionally substituted with one or more groups -RY.
(91 ) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated C5-6cycloalkyl.
(92) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated cyclopentyl, and is optionally substituted with one or more groups -RY.
(93) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated cyclopentyl.
(94) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated cyclohexyl, and is optionally substituted with one or more groups -RY. (95) A compound according to any one of (1 ) to (86), wherein each -A3B1, if present, is saturated cyclohexyl.
The Group -A' (96) A compound according to any one of (1 ) to (95), wherein each -A , if present, is C4-7cycloalkenyl. (97) A compound according to any one of (1 ) to (95), wherein each -A , if present, is independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl, and is optionally substituted with one or more groups -RY.
(98) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl.
(99) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is C5-6cycloalkenyl, and is optionally substituted with one or more groups -RY.
(100) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is C5-6cycloalkenyl. (101 ) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is independently cyclopentenyl or cyclohexenyl, and is optionally substituted with one or more groups -RY.
(102) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is independently cyclopentenyl or cyclohexenyl.
(103) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is cyclopentenyl, and is optionally substituted with one or more groups -RY. (104) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is cyclopentenyl.
(105) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is cyclopenten-3-yl. cyclopenten-3-yl
Figure imgf000031_0001
(106) A compound according to any one of (1 ) to (95), wherein each -A , if present, is cyclohexenyl, and is optionally substituted with one or more groups -RY.
(107) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is cyclohexenyl.
(108) A compound according to any one of (1 ) to (95), wherein each -A3B2, if present, is cyclohexenyl-1-yl. cyclohexen 1 -yl
Figure imgf000032_0001
The Group -A^
(109) A compound according to any one of (1 ) to (108), wherein each -A3C, if present, is phenyl.
The Group -A3D
(1 10) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is C5-6heteroaryl.
(1 1 1 ) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is C5heteroaryl, and is optionally substituted with one or more groups -RY.
(1 12) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is C5heteroaryl. (1 13) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is C6heteroaryl, and is optionally substituted with one or more groups -RY.
(1 14) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is C6heteroaryl.
(1 15) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazolyl,
[1 ,3,4]thiadiazolyl, [1 ,2,4]thiadiazolyl), pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, or triazinyl (e.g., [1 ,3,5]-triazinyl), and is optionally substituted with one or more groups -RY.
(1 16) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazolyl,
[1 ,3,4]thiadiazolyl, [1 ,2,4]thiadiazolyl), pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, or triazinyl (e.g., [1 ,3,5]-triazinyl). (1 17) A compound according to any one of (1 ) to (109), wherein each -A , if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, and is optionally substituted with one or more groups -RY.
(1 18) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl.
(1 19) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, and is optionally substituted with one or more groups -RY. (120) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl.
(121 ) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, and is optionally substituted with one or more groups -RY.
(122) A compound according to any one of (1 ) to (109), wherein each -A , if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl.
(123) A compound according to any one of (1 ) to (109), wherein each -A , if present, pyridyl, and is optionally substituted with one or more groups -RY.
(124) A compound according to any one of (1 ) to (109), wherein each -A3D, if present, pyridyl.
The Group -A 3E
(125) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is non-aromatic C4-7heterocyclyl.
(126) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is independently pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, azepanyl, or diazepanyl, and is optionally substituted with one or more groups -RY. (127) A compound according to any one of (1 ) to (124), wherein each -A , if present, is independently pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, dioxanyl, azepanyl, or diazepanyl. (128) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is independently pyrrolidino, piperidino, morpholino, piperazino, and is optionally substituted with one or more groups -RY.
(129) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is independently pyrrolidino, piperidino, morpholino, piperazino, or N-(Ci-4alkyl)-piperazino.
(130) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is piperidino, and is optionally substituted with one or more groups -RY. (131 ) A compound according to any one of (1 ) to (124), wherein each -A3E, if present, is piperidino.
The Group -L3- (132) A compound according to any one of (1 ) to (131 ), wherein each -L3-, if present, is independently -CH2-, -CH2CH2-, -CH(CH3)CH2-, -CH2CH(CH3)-, -C(CH3)2-.
(133) A compound according to any one of (1 ) to (131 ), wherein each -L3-, if present, is independently -CH2- or -CH2CH2-.
(134) A compound according to any one of (1 ) to (131 ), wherein each -L3-, if present, is -CH2-.
The Group -A' 4
(135) A compound according to any one of (1 ) to (134), wherein -A is independently -A' -A4B, -A4C, -L4-A4C, -A4D, or -L4-A4D
(136) A compound according to any one of (1 ) to (134), wherein -A4 is independently -A' -A4B, -A4C, -L4-A4C, or -A4D.
(137) A compound according to any one of (1 ) to (134), wherein -A4 is independently -A' -A4B. -A4C. or -L4-A4C. (138) A compound according to any one of (1 ) to (134), wherein -A4 is independently -A4A, -A4B, -A4C, or -A4D 139) A compound according to any one of (1 ) to (134), wherein -A is independently A4A, -A4B, or -A4C.
140) A compound according to any one of (1 ) to (134), wherein -A4 is -A' 4A
141 ) A compound according to any one of (1 ) to (134), wherein -A4 is -A'
142) A compound according to any one of (1 ) to (134), wherein -A4 is -L4-A'
143) A compound according to any one of (1 ) to (134), wherein -A4 is -A4C.
144) A compound according to any one of (1 ) to (134), wherein -A4 is -L4-A'
145) A compound according to any one of (1 ) to (134), wherein -A4 is -A4D.
146) A compound according to any one of (1 ) to (134), wherein -A4 is -L4-A' The Group -A4A
147) A compound according to any one of (1 ) to (146), wherein -A , if present, is -A
148) A compound according to any one of (1 ) to (146), wherein -A4A, if present, is -A
149) A compound according to any one of (1 ) to (146), wherein -A4A, if present, is -A The Group -A4A1
150) A compound according to any one of (1 ) to (149), wherein -A , if present, is saturated aliphatic C1-10alkyl substituted with one or more groups -RFA, and optionally is urther substituted with one or more groups -Rx.
151 ) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C1-10alkyl substituted with one or more groups -RFA.
152) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic Ci-8alkyl substituted with one or more groups -RFA, and optionally is urther substituted with one or more groups -Rx.
153) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic Ci-8alkyl substituted with one or more groups -RFA. (154) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C1-6alkyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(155) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic Ci-6alkyl substituted with one or more groups -RFA.
(156) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C4-8alkyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(157) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C4-8alkyl substituted with one or more groups -RFA.
(158) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C5-6alkyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx. (159) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C5-6alkyl substituted with one or more groups -RFA.
(160) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C5alkyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(161 ) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is
FA
saturated aliphatic C5alkyl substituted with one or more groups -R
(162) A compound according to any one of (1 ) to (149), wherein -A , if present, is saturated aliphatic C6alkyl substituted with on ee or more groups -RFA, and optionally is further substituted with one or more groups -R>
(163) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is saturated aliphatic C6alkyl substituted with one or more groups -RFA.
(164) A compound according to any one of (150) to (163), wherein said "one or more groups -RFA" is "exactly one group -RFA". (165) A compound according to any one of (1 ) to (149), wherein -A , if present, is independently:
Figure imgf000037_0001
, or
(166) A compound according to any one of (1 ) to (149), wherein -A , if present, is:
(167) A compound according to any one of (1 ) to (149), wherein -A , if present, is
Figure imgf000037_0002
(168) A compound according to any , wherein -A , if present, is
Figure imgf000037_0003
(169) A compound according to any , wherein -A , if present, is
Figure imgf000037_0004
(170) A compound according to any one of (1 ) to (149), wherein -A , if present, is independently:
Figure imgf000037_0005
(171 ) A compound according to any one of (1 ) to (149), wherein -A4A1, if present, is (172) A compound according to a wherein -A , if present, is:
Figure imgf000038_0001
(173) A compound according to a wherein -A , if present, is:
Figure imgf000038_0002
(174) A compound according to a wherein -A , if present, is:
Figure imgf000038_0003
The Group -A'
(175) A compound according to any one of (1 ) to (174), wherein -A , if present, is aliphatic C2-ioalkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(176) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C2-ioalkenyl substituted with one or more groups -RFA. (177) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C3-i0alkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(178) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C3-i0alkenyl substituted with one or more groups -RFA.
(179) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C2-8alkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(180) A compound according to any one of (1 ) to (174), wherein -A , if present, is aliphatic C2-8alkenyl substituted with one or more groups -RFA. (181 ) A compound according to any one of (1 ) to (174), wherein -A , if present, is aliphatic C3-8alkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(182) A compound according to any one of (1 ) to (174), wherein -A , if present, is aliphatic C3-8alkenyl substituted with one or more groups -RFA.
(183) A compound according to any one of (1 ) to (174), wherein -A , if present, is aliphatic C2-6alkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(184) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C2-6alkenyl substituted with one or more groups -RFA. (185) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C3-6alkenyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(186) A compound according to any one of (1 ) to (174), wherein -A4A2, if present, is aliphatic C3-6alkenyl substituted with one or more groups -RFA.
(187) A compound according to any one of (175) to (186), wherein said "one or more groups -RFA" is "exactly one group -RFA".
(188) A compound according to any one of (1 ) to (174), wherein -A , if present, is independently:
Figure imgf000039_0001
(189) A compound according to any (174), wherein -A , if present, is:
Figure imgf000039_0002
(190) A compound according to any one of (1 ) to (174), wherein -A , if present, is:
Figure imgf000039_0003
The Group -A4A3
(191 ) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C2-ioalkynyl substituted with o innee or more groups -R , and optionally is further substituted with one or more groups -Rx.
(192) A compound according to any one of (1 ) to (190), wherein -A , if present, is aliphatic C2-ioalkynyl substituted with one or more groups -RFA. (193) A compound according to any one of (1 ) to (190), wherein -A , if present, is aliphatic C3-i0alkynyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(194) A compound according to any one of (1 ) to (190), wherein -A , if present, is aliphatic C3-i0alkynyl substituted with one or more groups -RFA.
(195) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C2-8alkynyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(196) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C2-8alkynyl substituted with one or more groups -RFA.
(197) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C3-8alkynyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
(198) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C3-8alkynyl substituted with one or more groups -RFA.
(199) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C2-6alkynyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx. (200) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C2-6alkynyl substituted with one or more groups -RFA.
(201 ) A compound according to any one of (1 ) to (190), wherein -A4A3, if present, is aliphatic C3-6alkynyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx. (202) A compound according to any one of (1 ) to (190), wherein -A , if present, is aliphatic C3-6alkynyl substituted with one or more groups -RFA.
(203) A compound according to any one of (191 ) to (202), wherein said "one or more groups -RFA" is "exactly one group -RFA".
(204) A compound according to a wherein -A4A3, if present, is:
Figure imgf000041_0001
The Group -A'
(205) A compound according to any one of (1 ) to (204), wherein each -A , if present, is -A4B1. (206) A compound according to any one of (1 ) to (204), wherein each -A4B, if present, is
Λ 4Β2
The Group -A' (207) A compound according to any one of (1 ) to (206), wherein each -A , if present, is saturated C3-7cycloalkyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(208) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated C3-7cycloalkyl substituted with one or more groups -RFB.
(209) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated C4-6cycloalkyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(210) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated C4-6cycloalkyl substituted with one or more groups -RFB.
(21 1 ) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated C5-6cycloalkyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(212) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is
FB
saturated C5-6cycloalkyl substituted with one or more groups -R . (213) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated cyclopentyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(214) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated cyclopentyl substituted with one or more groups -RFB.
(215) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated cyclohexyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(216) A compound according to any one of (1 ) to (206), wherein each -A4B1, if present, is saturated cyclohexyl substituted with one or more groups -RFB.
(217) A compound according to any one of (207) to (216), wherein said "one or more groups -RFB" is "exactly one group -RFB".
The Group -A4B2
(218) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is C4-7cycloalkenyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY. (219) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is C4-7cycloalkenyl substituted with one or more groups -RFB.
(220) A compound according to any one of (1 ) to (217), wherein each -A , if present, independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl, substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(221 ) A compound according to any one of (1 ) to (217), wherein each -A , if present, independently cyclobutenyl, cyclopentenyl, cyclohexenyl, or cycloheptenyl, substituted with one or more groups -RFB.
(222) A compound according to any one of (1 ) to (217), wherein each -A , if present, is C5-6cycloalkenyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY. (223) A compound according to any one of (1 ) to (217), wherein each -A , if present, is C5-6cycloalkenyl substituted with one or more groups -RFB.
(224) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is independently cyclopentenyl or cyclohexenyl, substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY.
(225) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is independently cyclopentenyl or cyclohexenyl, substituted with one or more groups -RFB.
(226) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is cyclopentenyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY. (227) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is cyclopentenyl substituted with one or more groups -RFB.
(228) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is cyclopenten-3-yl substituted with one or more groups -RFB.
(229) A compound according to any one of (1 ) to (217), wherein each -A4 , if present, is cyclohexenyl substituted with one or more groups -RFB, and optionally is further substituted with one or more groups -RY. (230) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is cyclohexenyl substituted with one or more groups -RFB.
(231 ) A compound according to any one of (1 ) to (217), wherein each -A4B2, if present, is cyclohexenyl-1-yl substituted with one or more groups -RFB.
(232) A compound according to any one of (218) to (231 ), wherein said "one or more groups -RFB" is "exactly one group -RFB".
The Group -A' 4C
(233) A compound according to any one of (1 ) to (232), wherein each -A4C, if present, is phenyl substituted with one or more groups -RFC, and optionally is further substituted with one or more groups -RY. (234) A compound according to any one of (1 ) to (232), wherein each -A4C, if present, is phenyl substituted with one or more groups -RFC. (235) A compound according to any one of (233) to (234), wherein said "one or more groups -RFC" is "exactly one group -RFC".
(236) A compound according to any one of (1 ) to (232), wherein each -A4C, if present, independently:
Figure imgf000044_0001
(237) A compound according to any one of (1 ) to (232), wherein each -A , if present, is:
Figure imgf000044_0002
(238) A compound according to any on (232), wherein each -A , if present, is:
Figure imgf000044_0003
(239) A compound according to any one to (232), wherein each -A , if present,
Figure imgf000044_0004
The Group -A' (240) A compound according to any one of (1 ) to (239), wherein each -A , if present, is C5-6heteroaryl substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY.
(241 ) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is C5-6heteroaryl substituted with one or more groups -RFD.
(242) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is C5heteroaryl substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY. (243) A compound according to any one of (1 ) to (239), wherein each -A , if present, is C5heteroaryl substituted with one or more groups -RFD.
(244) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is C6heteroaryl substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY.
(245) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is C6heteroaryl substituted with one or more groups -RFD.
(246) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazolyl,
[1 ,3,4]thiadiazolyl, [1 ,2,4]thiadiazolyl), pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, or triazinyl (e.g., [1 ,3,5]-triazinyl), substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY. (247) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl (e.g., 1 H-[1 ,2,3]triazolyl, 2H-[1 ,2,3]triazolyl, 4H-[1 ,2,4]triazolyl, 1 H-[1 ,2,4]triazolyl), oxadiazolyl (e.g., [1 ,2,3]oxadiazolyl, furazanyl, [1 ,3,4]oxadiazolyl, [1 ,2,4]oxadiazolyl), thiadiazolyl (e.g., [1 ,2,3]thiadiazolyl, [1 ,2,5]thiadiazolyl,
[1 ,3,4]thiadiazolyl, [1 ,2,4]thiadiazolyl), pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, or triazinyl (e.g., [1 ,3,5]-triazinyl), substituted with one or more groups -RFD.
(248) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY.
(249) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -RFD.
(250) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY. (251 ) A compound according to any one of (1 ) to (239), wherein each -A , if present, is independently furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, or isothiazolyl, substituted with one or more groups -RFD.
(252) A compound according to any one of (1 ) to (239), wherein each -A , if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY. (253) A compound according to any one of (1 ) to (239), wherein each -A4D, if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -RFD.
(254) A compound according to any one of (1 ) to (239), wherein each -A , if present, is pyridyl substituted with one or more groups -RFD, and is optionally substituted with one or more groups -RY.
(255) A compound according to any one of (1 ) to (239), wherein each -A , if present, is independently pyridyl substituted with one or more groups -RFD.
(256) A compound according to any one of (240) to (255), wherein said "one or more groups -RFD" is "exactly one group -RFD".
The Group -L4-
(257) A compound according to any one of (1 ) to (256), wherein each -L4-, if present, is independently -CH2-, -CH2CH2-, -CH(CH3)CH2-, -CH2CH(CH3)-, -C(CH3)2-.
(258) A compound according to any one of (1 ) to (256), wherein each -L4-, if present, is independently -CH2- or -CH2CH2-.
(259) A compound according to any one of (1 ) to (256), wherein each -L4-, if present, is -CH2-. The Group -RFB
(260) A compound according to any one of (1 ) to (259), wherein each -RFB, if present, is -RF1.
(261 ) A compound according to any one of (1 ) to (259), wherein each -R , if present, is -RF2. The Group -R' FC
(262) A compound according to any one of (1 ) to (261 ), wherein each -RFC, if present, is -R' F1
(263) A compound according to any one of (1 ) to (261 ), wherein each -RFC, if present, is -RF2. The Group -RFD
(264) A compound according to any one of (1 ) to (263), wherein each -RFD, if present, is
-R F1. (265) A compound according to any one of (1 ) to (263), wherein each -R , if present, is -RF2.
The Group -RF2 (266) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic Ci-4alkyl group substituted with one or more 18F atoms.
(267) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic C1-4alkyl group substituted with exactly one 18F atom.
(268) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic Ci-3alkyl group substituted with one or more 18F atoms.
(269) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic C1-3alkyl group substituted with exactly one 18F atom.
(270) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic Ci-2alkyl group substituted with one or more 18F atoms. (271 ) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic C1-2alkyl group substituted with exactly two 18F atoms.
(272) A compound according to any one of (1 ) to (265), wherein each -RF2, if present, is a saturated aliphatic C1-2alkyl group substituted with exactly one 18F atom. The Optional Substituents -R
(273) A compound according to any one of (1 ) to (272), wherein each -Rx, if present, is independently selected from:
-F, -CI, -Br, -I, -CF3, phenyl, -OH, -ORs, -OCF3, -NH2, -NHRS, -NRS 2, pyrrolidine piperidino, morpholino, piperazino, N-(d-4alkyl)-piperazino, -NHC(=0)Rs, -NRsC(=0)Rs, -C(=0)Rs, -C(=0)OH, -C(=0)ORs, -C(=0)NH2, -C(=0)NHRs, -C(=0)NRs 2,
-C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino,
-C(=0)-{N-(Ci.4alkyl)-piperazino}-, -SRS, -S(=0)Rs, -S(=0)2Rs, -S(=0)2NH2,
Figure imgf000048_0001
-S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino, -S(=0)2-piperazino, -S(=0)2-{N-(Ci-4alkyl)-piperazino}-, -NHS(=0)2Rs, and -NRsS(=0)2Rs; wherein each -Rs is independently saturated aliphatic Ci-6alkyl, phenyl, or
-CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups
independently selected from: -F, -CI, -Br, -I, -Rss, -CF3, -OH, -ORss, -OCF3, -NH2, -NHRSS, and -NRSS 2, wherein each -Rss is saturated aliphatic C^alkyl.
(274) A compound according to (273), wherein each -Rx, if present, is independently selected from:
-F, -CI, -Br, -I, -CF3, phenyl, -OH, -ORs, -OCF3, -NH2, -NHRS, -NRS 2, pyrrolidine piperidino, morpholino, piperazino, N-(Ci-4alkyl)-piperazino, -NHC(=0)Rs, -NRsC(=0)Rs, -C(=0)Rs, -C(=0)OH, -C(=0)ORs, -C(=0)NH2, -C(=0)NHRs, -C(=0)NRs 2,
-C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino, and -C(=0)-{N-(C1-4alkyl)-piperazino}-.
(275) A compound according to (273), wherein each -Rx, if present, is independently selected from:
-F, -CI, -Br, -I, -CF3, phenyl, -OH, -ORs, -OCF3, -NH2, -NHRS, -NRS 2, pyrrolidine piperidino, morpholino, piperazino, and N-(Ci-4alkyl)-piperazino.
(276) A compound according to (273), wherein each -Rx, if present, is independently selected from: -F, -CI, -Br, -I, -OH, and -ORs.
(277) A compound according to (273), wherein each -Rx, if present, is independently selected from: -F, -CI, -Br, and -I.
(278) A compound according to (273), wherein each -Rx, if present, is independently selected from: -CI and -Br. (279) A compound according to (273), wherein each -Rx, if present, is -CI. (280) A compound according to (273), wherein each -R , if present, is -Br.
(281 ) A compound according to any one of (273) to (280), wherein each -Rs is saturated aliphatic Ci-6alkyl.
(282) A compound according to any one of (273) to (280), wherein each -Rs is saturated aliphatic Ci-4alkyl.
(283) A compound according to any one of (273) to (282), wherein each -Rss is independently -Me or -Et.
(284) A compound according to any one of (273) to (282), wherein each -Rss is -Me. The Optional Substituents -RY
(285) A compound according to any one of (1 ) to (284), wherein each -RY, if present, is independently selected from:
-F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidine piperidino, morpholino, piperazino, N-(Ci-4alkyl)-piperazino, -NHC(=0)RT, -NRTC(=0)RT, -C(=0)RT, -C(=0)OH, -C(=0)ORT, -C(=0)NH2, -C(=0)NHRT, -C(=0)NRT 2, -C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino,
-C(=0)-{N-(Ci.4alkyl)-piperazino}-, -SRT, -S(=0)RT, -S(=0)2RT, -S(=0)2NH2, -S(=0)2NHRT, -S(=0)2NRT 2, -S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino,
-S(=0)2-piperazino, -S(=0)2-{N-(C1-4alkyl)-piperazino}-, -NHS(=0)2RT, and -NRTS(=0)2RT; wherein each -RT is independently saturated aliphatic Ci-6alkyl, phenyl, or
-CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups
independently selected from: -F, -CI, -Br, -I, -RTT, -CF3, -OH, -ORTT, -OCF3, -NH2, -NHRTT, or -NRTT 2, wherein each -RTT is saturated aliphatic Ci-4alkyl.
(286) A compound according to (285), wherein each -RY, if present, is independently selected from:
-F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidino, piperidino, morpholino, piperazino, N-(C1-4alkyl)-piperazino, -NHC(=0)RT, -NRTC(=0)RT, -C(=0)RT, -C(=0)OH, -C(=0)ORT, -C(=0)NH2, -C(=0)NHRT, -C(=0)NRT 2, -C(=0)-pyrrolidino, -C(=0)-piperidino, -C(=0)-morpholino, -C(=0)-piperazino, and -C(=0)-{N-(Ci-4alkyl)-piperazino}-.
(287) A compound according to (285), wherein each -RY, if present, is independently selected from: -F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidino, piperidino, morpholino, piperazino, and N-(Ci-4alkyl)-piperazino.
(288) A compound according to (285), wherein each -RY, if present, is independently selected from: -F, -CI, -Br, -I, -RT, -OH, and -ORT.
(289) A compound according to (285), wherein each -RY, if present, is independently selected from: -F, -CI, -Br, -I, and -RT. (290) A compound according to (285), wherein each -RY, if present, is independently selected from: -F, -CI, -Br, and -I.
(291 ) A compound according to (285), wherein each -RY, if present, is independently selected from: -CI and -Br.
(292) A compound according to (285), wherein each -RY, if present, is -CI.
(293) A compound according to (285), wherein each -RY, if present, is -Br. (294) A compound according to (285), wherein each -RY, if present, is -RT.
(295) A compound according to any one of (285) to (294), wherein each -RT is saturated aliphatic Ci-6alkyl. (296) A compound according to any one of (285) to (294), wherein each -RT is saturated aliphatic C1-4alkyl.
(297) A compound according to any one of (285) to (294), wherein each -RTT is saturated aliphatic Ci-6alkyl.
(298) A compound according to any one of (285) to (294), wherein each -RTT is saturated aliphatic C1-4alkyl.
(299) A compound according to any one of (285) to (298), wherein each -RTT is independently -Me or -Et.
(300) A compound according to any one of (285) to (298), wherein each -RTT is -Me. Stereoisomerism about -A3 and -A4 (301 ) A compound according to any one of claims (1 ) to (300), wherein -A3 and -A4 are different, and the carbon atom to which -A3 and -A4 are attached is in the (R) configuration. (302) A compound according to any one of claims (1 ) to (300), wherein -A3 and -A4 are different, and the carbon atom to which -A3 and -A4 are attached is in the (S) configuration.
Specific Compounds
(303) A compound according to (1 ), selected from compounds of the following formulae and pharmaceutically acceptable salts, hydrates, and solvates thereof:
Figure imgf000051_0001
Figure imgf000052_0001
Combinations
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. All combinations of the embodiments pertaining to the chemical groups represented by the variables (e.g., =X, -A1, -A1A, -A1B, -A2, -A2A, -A2B, -A3, -Α4Β, -Α4Β1, -Α4Β2, -A4C, -A4D, -L4-, -RFA, -RFB, -RFC, -RFD, -RF1, -RF2, -Rx, -Rs, -Rss, -RY, -RT, -RTT, etc.) are specifically embraced by the present invention and are disclosed herein just as if each and every combination was individually and explicitly disclosed, to the extent that such combinations embrace compounds that are stable compounds
(i.e., compounds that can be isolated, characterised, and tested for biological activity). In addition, all sub-combinations of the chemical groups listed in the embodiments describing such variables are also specifically embraced by the present invention and are disclosed herein just as if each and every such sub-combination of chemical groups was individually and explicitly disclosed herein. Substantially Purified Forms
One aspect of the present invention pertains to 18FBAR compounds, as described herein, in substantially purified form and/or in a form substantially free from contaminants. In one embodiment, the substantially purified form is at least 50% by weight, e.g., at least 60% by weight, e.g., at least 70% by weight, e.g., at least 80% by weight, e.g., at least 90% by weight, e.g., at least 95% by weight, e.g., at least 97% by weight, e.g., at least 98% by weight, e.g., at least 99% by weight. Unless specified, the substantially purified form refers to the compound in any
stereoisomeric or enantiomeric form. For example, in one embodiment, the substantially purified form refers to a mixture of stereoisomers, i.e., purified with respect to other compounds. In one embodiment, the substantially purified form refers to one
stereoisomer, e.g., optically pure stereoisomer. In one embodiment, the substantially purified form refers to a mixture of enantiomers. In one embodiment, the substantially purified form refers to a equimolar mixture of enantiomers (i.e., a racemic mixture, a racemate). In one embodiment, the substantially purified form refers to one enantiomer, e.g., optically pure enantiomer. In one embodiment, the contaminants represent no more than 50% by weight, e.g., no more than 40% by weight, e.g., no more than 30% by weight, e.g., no more than 20% by weight, e.g., no more than 10% by weight, e.g., no more than 5% by weight, e.g., no more than 3% by weight, e.g., no more than 2% by weight, e.g., no more than 1 % by weight.
Unless specified, the contaminants refer to other compounds, that is, other than stereoisomers or enantiomers. In one embodiment, the contaminants refer to other compounds and other stereoisomers. In one embodiment, the contaminants refer to other compounds and the other enantiomer.
In one embodiment, the substantially purified form is at least 60% optically pure (i.e., 60% of the compound, on a molar basis, is the desired stereoisomer or enantiomer, and 40% is the undesired stereoisomer or enantiomer), e.g., at least 70% optically pure, e.g., at least 80% optically pure, e.g., at least 90% optically pure, e.g., at least 95% optically pure, e.g., at least 97% optically pure, e.g., at least 98% optically pure, e.g., at least 99% optically pure.
Isomers
Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diastereoisomeric, epimeric, atropic, stereoisomeric, tautomeric, conformational, or anomeric forms, including but not limited to, cis- and trans-forms; E- and Z-forms; c-, t-, and r- forms; endo- and exo-forms; R-, S-, and meso-forms; D- and L-forms; d- and l-forms; (+) and (-) forms; keto-, enol-, and enolate-forms; syn- and anti-forms; synclinal- and anticlinal-forms; a- and β-forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as "isomers" (or "isomeric forms").
A reference to a class of structures may well include structurally isomeric forms falling within that class (e.g., C1-7alkyl includes n-propyl and iso-propyl; butyl includes n-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl). However, reference to a specifc group or substitution pattern is not intended to include other structural (or constitutional isomers) which differ with respect to the connections between atoms rather than by positions in space. For example, a reference to a methoxy group, -OCH3, is not to be construed as a reference to its structural isomer, a
hydroxymethyl group, -CH2OH. Similarly, a reference to ortho-chlorophenyl is not to be construed as a reference to its structural isomer, meta-chlorophenyl.
The above exclusion does not pertain to tautomeric forms, for example, keto-, enol-, and enolate-forms, as in, for example, the following tautomeric pairs: keto/enol (illustrated below), imine/enamine, amide/imino alcohol, amidine/amidine, nitroso/oxime,
thioketone/enethiol, N-nitroso/hydroxyazo, and nitro/aci-nitro.
Figure imgf000055_0001
keto enol enolate
Note that specifically included in the term "isomer" are compounds with one or more isotopic substitutions, with the exception that: where 18F is indicated, 18F is specifically intended (and not some other isotope of fluorine). For example, H may be in any isotopic form, including 1H, 2H (D), and 3H (T); C may be in any isotopic form, including 12C, 13C, and 14C; O may be in any isotopic form, including 160 and 180; and the like.
Unless otherwise specified, a reference to a particular compound includes all such isomeric forms, including mixtures (e.g., racemic mixtures) thereof. Methods for the preparation (e.g., asymmetric synthesis) and separation (e.g., fractional crystallisation and chromatographic means) of such isomeric forms are either known in the art or are readily obtained by adapting the methods taught herein, or known methods, in a known manner.
Salts
It may be convenient or desirable to prepare, purify, and/or handle a corresponding salt of the compound, for example, a pharmaceutically-acceptable salt. Examples of
pharmaceutically acceptable salts are discussed in Berge et al., 1977, "Pharmaceutically Acceptable Salts," J. Pharm. Sci., Vol. 66, pp. 1 -19.
When -A1 and/or -A2 is -H, the ring core of the compounds has one or two secondary amino groups (-NH-). One of these secondary amino groups may be de-protonated to give an anionic group (-N'"'-), which may form a salt with a suitable cation (e.g., Na+, K+). For example, many known barbiturates are prepared and handled as the sodium salt: see, e.g., Hexobarbital, Butabarbital sodium, Hexethal sodium, Pentobarbital sodium, Thiopental sodium, Vinbarbital sodium, and Secobarbital.
And so, for the avoidance of doubt, the term "pharmaceutically acceptable salt thereof" encompasses the following salts, wherein Z+ is a suitable cation (e.g., Na+, K+) or a suitable combination or sub-combination of cations (e.g., 1/2Ca2+):
Figure imgf000056_0001
Additionally, if the compound is anionic, or has a functional group which may be anionic (e.g., -COOH may be -COO"), then a salt may be formed with a suitable cation.
Examples of suitable inorganic cations include, but are not limited to, alkali metal ions such as Na+ and K+, alkaline earth cations such as Ca2+ and Mg2+, and other cations such as Α 3. Examples of suitable organic cations include, but are not limited to, ammonium ion (i.e., NH4 +) and substituted ammonium ions (e.g., NH3R+, NH2R2+, NHR3 +, NR4 +). Examples of some suitable substituted ammonium ions are those derived from:
ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine. An example of a common quaternary ammonium ion is N(CH3)4 +.
If the compound is cationic, or has a functional group which upon protonation may become cationic (e.g., -NH2 may become -NH3 +), then a salt may be formed with a suitable anion. Examples of suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids: hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfurous, nitric, nitrous, phosphoric, and phosphorous. Examples of suitable organic anions include, but are not limited to, those derived from the following organic acids: 2-acetyoxybenzoic, acetic, trifluoroacetic, ascorbic, aspartic, benzoic, camphorsulfonic, cinnamic, citric, edetic, ethanedisulfonic, ethanesulfonic, fumaric, glucheptonic, gluconic, glutamic, glycolic, hydroxymaleic, hydroxynaphthalene carboxylic, isethionic, lactic, lactobionic, lauric, maleic, malic, methanesulfonic, mucic, oleic, oxalic, palmitic, pamoic, pantothenic, phenylacetic, phenylsulfonic, propionic, pyruvic, salicylic, stearic, succinic, sulfanilic, tartaric, toluenesulfonic, and valeric. Examples of suitable polymeric organic anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl cellulose.
Unless otherwise specified, a reference to a particular compound also includes salt forms thereof.
Solvates and Hydrates
It may be convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the compound. The term "solvate" is used herein in the conventional sense to refer to a complex of solute (e.g., compound, salt of compound) and solvent. If the solvent is water, the solvate may be conveniently referred to as a hydrate, for example, a mono-hydrate, a di-hydrate, a tri-hydrate, etc. Unless otherwise specified, a reference to a particular compound also includes solvate and hydrate forms thereof.
Chemically Protected Forms It may be convenient or desirable to prepare, purify, and/or handle the compound in a chemically protected form. The term "chemically protected form" is used herein in the conventional chemical sense and pertains to a compound in which one or more reactive functional groups are protected from undesirable chemical reactions under specified conditions (e.g., pH, temperature, radiation, solvent, and the like). In practice, well known chemical methods are employed to reversibly render unreactive a functional group, which otherwise would be reactive, under specified conditions. In a chemically protected form, one or more reactive functional groups are in the form of a protected or protecting group (also known as a masked or masking group or a blocked or blocking group). By protecting a reactive functional group, reactions involving other unprotected reactive functional groups can be performed, without affecting the protected group; the protecting group may be removed, usually in a subsequent step, without substantially affecting the remainder of the molecule. See, for example, Protective Groups in Organic Synthesis (T. Green and P. Wuts; 4th Edition; John Wiley and Sons, 2006). A wide variety of such "protecting," "blocking," or "masking" methods are widely used and well known in organic synthesis. For example, a compound which has two nonequivalent reactive functional groups, both of which would be reactive under specified conditions, may be derivatized to render one of the functional groups "protected," and therefore unreactive, under the specified conditions; so protected, the compound may be used as a reactant which has effectively only one reactive functional group. After the desired reaction (involving the other functional group) is complete, the protected group may be "deprotected" to return it to its original functionality.
For example, a hydroxy group may be protected as an ether (-OR) or an ester
(-OC(=0)R), for example, as: a t-butyl ether; a benzyl, benzhydryl (diphenylmethyl), or trityl (triphenylmethyl) ether; a trimethylsilyl or t-butyldimethylsilyl ether; or an acetyl ester (-OC(=0)CH3, -OAc).
For example, an aldehyde or ketone group may be protected as an acetal (R-CH(OR)2) or ketal (R2C(OR)2), respectively, in which the carbonyl group (>C=0) is converted to a diether (>C(OR)2), by reaction with, for example, a primary alcohol. The aldehyde or ketone group is readily regenerated, for example, by hydrolysis using water in the presence of acid. For example, an amine group may be protected, for example, as an amide (-NRCO-R) or a urethane (-NRCO-OR), for example, as: a methyl amide (-NHCO-CH3); a benzyloxy amide (-NHCO-OCH2C6H5, -NH-Cbz); as a t-butoxy amide (-NHCO-OC(CH3)3, -NH-Boc); a 2-biphenyl-2-propoxy amide
Figure imgf000058_0001
-NH-Bpoc), as a
9-fluorenylmethoxy amide (-NH-Fmoc), as a 6-nitroveratryloxy amide (-NH-Nvoc), as a 2-trimethylsilylethyloxy amide (-NH-Teoc), as a 2,2,2-trichloroethyloxy amide (-NH-Troc), as an allyloxy amide (-NH-Alloc), as a 2(-phenylsulfonyl)ethyloxy amide (-NH-Psec); or, in suitable cases (e.g., cyclic amines), as a nitroxide radical (>Ν-0·).
For example, a carboxylic acid group may be protected as an ester for example, as: an Ci-7alkyl ester (e.g., a methyl ester; a t-butyl ester); a Ci-7haloalkyl ester (e.g., a
C1-7trihaloalkyl ester); a triC1-7alkylsilyl-C1-7alkyl ester; or a C5-2oaryl-C1-7alkyl ester (e.g., a benzyl ester; a nitrobenzyl ester); or as an amide, for example, as a methyl amide.
For example, a thiol group may be protected as a thioether (-SR), for example, as: a benzyl thioether; an acetamidomethyl ether (-S-CH2NHC(=0)CH3).
Chemical Synthesis
Methods for the chemical synthesis of the 18FBAR compounds (as described herein) are described herein. These and/or other well-known methods may be modified and/or adapted in known ways in order to facilitate the synthesis of additional 18FBAR
compounds (as described herein).
In one approach, an appropriate mono-substituted diethyl malonate is deprotonated and reacted with a suitably protected bromoalcohol, to give a di-substituted diethyl malonate, which is then cyclised with a suitable urea to give the 5,5'-disubstituted barbiturate. The protecting group is then removed from the alcohol and a suitable leaving group is introduced and then displaced with suitably activated 18F-fluoride.
For example, diethyl 2-ethylmalonate is deprotected with sodium hydride in a solvent such as DMF and reacted with a benzyl-protected bromoalcohol. The resulting diethylmalonate is then reacted with urea in dry DMF and the benzyl protecting group removed by hydrogenation, for example, with 20 % palladium (II) hydroxide on carbon in a solvent such as methanol. The alcohol is then reacted with toluenesulfonyl chloride, for example, in a solvent such as chloroform containing a suitable base, for example, pyridine. Finally, the tosyl group is displaced by K18F in the presence of a suitable phase-transfer agent, for example, Kryptofix 222®, in a suitable solvent, for example, acetonitrile, to give the target 18F labelled compound.
An example of such a method is illustrated in the following scheme.
Scheme 1
Figure imgf000059_0001
In another approach, the corresponding F compound is prepared as an analytical standard to allow characterisation of the corresponding 18F compound. The alcohol is prepared as described in Scheme 1 above, and then reacted with a suitable fluorinating agent at low temperature, for example, with diethylaminosulfur trifluoride (DAST) in a suitable solvent, for example, chloroform at -4°C or dimethoxyethane (DME) at -78°C.
An example of such a method is illustrated in the following scheme. Scheme 2
Figure imgf000060_0001
In another approach, the corresponding thio-compound is prepared by following a methodology similar to the one shown in Scheme 1 above, and using a suitable thiourea and a suitable alcohol protecting group, that is, one which can be removed under conditions not affected by the presence of sulfur, for example, a methoxymethylether, i-butyldiphenyl silyl ether (OTBDPS), f-butyldimethyl silyl ether (OTBDMS) or tetrahydropyranyl ether (OTHP), which can be removed by reaction of the bromoalcohol with methoxymethyl chloride, i-butyldiphenyl silyl chloride, or dihydropyran, respectively. (See, e.g., Greene and Wuts, Protective Groups in Organic Synthesis, 1999, J. Wiley, New York, pp. 23-148). For example, the required bromoalcohol is protected as described above and then reacted with a mono-substituted diethyl malonate as shown in Scheme 1 above. The resulting di-substituted diethyl malonate is then cyclised with an appropriately substituted thiourea, to give the thiobarbiturate. The hydroxyl protecting group is then removed; for example, the silyl ether group is removed by reaction with tert-butylammonium fluoride, and the tetrahydropyranyl group and methoxymethyl ether are removed under acidic conditions (e.g., HCI). The alcohol derivative is then used to prepare the 18F or 19F compounds as shown in Schemes 1 and 2 above. Other methods for protection and deprotection of alcohols are described, for example, in Greene and Wuts, Protective Groups in Organic Synthesis, 1999, J. Wiley, New York, pp. 23-148.
An example of such a method is illustrated in the following scheme.
Figure imgf000061_0001
In another approach, the starting mono-substituted diethyl malonate is prepared by reaction of diethyl malonate with an appropriately substituted alkyl halide or tosylate. For example, diethyl malonate is deprotonated with sodium hydride in dry DMF and reacted with an alkyl bromide, for example, a branched alkyl bromide or cycloalkyi bromide. The mono-substituted diethyl malonate is then further reacted as described in the above schemes.
An example of such a method is illustrated in the following scheme.
Figure imgf000061_0002
In another approach, the starting mono-substituted dialkyl malonate is prepared by reaction of an appropriate ethyl ester with diethyl carbonate. For example, ethyl
4-methylpentanoate is deprotonated with LDA in dry THF and reacted with
diethylcarbonate, to give the appropriately mono-substituted diethyl malonate, which then further reacted as described in the above schemes to give the corresponding fluorinated compound.
An example of such a method is illustrated in the following scheme.
Scheme 5
Figure imgf000062_0001
In another approach, different substituents are introduced onto the nitrogen atoms of the barbiturate or thiobarbiturate ring by the use of an appropriately mono- or di-substituted urea or thiourea. For example, A/-methylurea, A/-phenylthiourea or /V,/V-dimethylurea may be used.
Examples of such methods are illustrated in the following scheme. Scheme 6
Figure imgf000062_0002
Figure imgf000063_0001
In another approach, different substituents are introduced onto the nitrogen atoms of the barbiturate or thiobarbiturate ring by deprotonation and reaction with an appropriate alkyl or aryl group bearing a suitable leaving group. For example, the barbiturate or thiobarbiturate is deprotonated with sodium hydride in dry DMF and then reacted with one equivalent of an alkyl halide, mesylate, triflate or tosylate. The process may be repeated to introduce a second different substituent. The compounds produced are then further reacted as described in the above schemes in order to give the corresponding fluorinated compounds.
An example of such a method is illustrated in the following scheme.
Scheme 7
Figure imgf000063_0002
In another approach, the fluorine atom is introduced onto an aryl group, for example, by reduction of an aromatic nitro group to give an aromatic amine, which is then trimethylated to give a quarternary ammonium cation, which is then displaced by a suitably activated fluoride anion. For example, the nitro group can be reduced with H2/10% palladium on carbon and the amine methylated with methyl iodide in excess in the presence of a suitable base such as potassium carbonate, in a suitable solvent such as DMF. Finally the quarternary ammonium cation is displaced with K18F in a solvent such as DMSO or acetonitrile at high temperatures, for example, 120-140°C.
An example of such a method is illustrated in the following scheme.
Figure imgf000064_0001
Compositions One aspect of the present invention is a composition (e.g., a pharmaceutical composition) comprising an 18FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
Another aspect of the present invention is a method of preparing a composition (e.g., a pharmaceutical composition) comprising admixing an 18FBAR compound, as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient. Uses
The 18FBAR compounds described herein are useful, for example, as imaging agents in positron emission imaging, for example, positron emission tomography (PET) imaging. Such positron emission imaging (e.g., PET imaging) is useful, for example, in methods of diagnosis, prognosis, and therapeutic monitoring.
Methods of Imaging One aspect of the invention is an 18FBAR compound as described herein for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
One aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject.
One aspect of the invention is a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of (e.g., a part of, the whole of) a human or animal subject employing an 18FBAR compound as described herein as an imaging agent.
In one embodiment, the method of positron emission imaging (e.g., positron emission tomography (PET) imaging) comprises the following steps:
(i) introducing the 18FBAR compound into the subject;
(ii) imaging (e.g., a part of, the whole of) the subject using positron emission (e.g., PET).
In one embodiment, the step of: (i) introducing the 18FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18FBAR compound (preferably as part of a pharmaceutically acceptable composition).
In this context, the term "effective amount" pertains to that amount of the 18FBAR compound, or a material, composition or dosage form comprising the 18FBAR compound, which is effective for producing some desired imaging effect, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
In one embodiment, the step of: (ii) imaging the subject is the step of: (ii) determining the presence and/or location and/or amount of 18FBAR compound in (e.g., a part of, the whole of) the subject using positron emission (e.g., using PET) imaging. Methods of PET imaging are well known. See, for example, Pimlott et al., 201 1 ;
Ametamey et al., 2008; Bergstrom et al., 2003; Czernin et al., 2002; Goh et al., 2003; Van Heertum et al., 2003; Massoud et al., 2003; Fowler et al., 1999; Kennedy et al., 1997. The use of 18F in PET imaging is discussed, for example, in Cai et al., 2008 and Miller et al., 2008.
Diagnosis/Prognosis
One aspect of the invention is an 18FBAR compound as described herein for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
In one embodiment, the 18FBAR compound is for use in a method of diagnosis.
In one embodiment, the 18FBAR compound is for use in a method of prognosis.
In one embodiment, the method of diagnosis or prognosis is practised on the human or animal body of the subject.
One aspect of the invention is an 18FBAR compound as described herein for use as a diagnostic or prognostic agent.
One aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use in a method of diagnosis or prognosis (e.g., of a disease or disorder in a subject).
In one embodiment, the medicament is for use in a method of diagnosis.
In one embodiment, the medicament is for use in a method of prognosis. One aspect of the invention is a method of diagnosis or prognosis of a disease or disorder in a subject which employs an 18FBAR compound as described herein.
In one embodiment, the method is a method of diagnosis. In one embodiment, the method is a method of prognosis. ln one embodiment, the method of diagnosis or prognosis comprises the following steps:
(i) introducing the 18FBAR compound into the subject;
(ii) determining the presence and/or location and/or amount of 18FBAR compound in the subject;
(iii) correlating the result of the determination made in (ii) with the presence, absence, or state of the disease or disorder.
In one embodiment, the step of: (i) introducing the 18FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18FBAR compound (preferably as part of a pharmaceutically acceptable composition).
In this context, the term "effective amount" pertains to that amount of the 18FBAR compound, or a material, composition or dosage form comprising the 18FBAR compound, which is effective for permitting some desired determination of the presence and/or location and/or amount of 18FBAR compound in the subject, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
In one embodiment, the determination of the presence and/or location and/or amount of 18FBAR compound in the subject is by positron emission (e.g., PET) imaging.
Therapeutic Monitoring
One aspect of the invention is an 18FBAR compound as described herein for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
In one embodiment, the method of therapeutic monitoring is practised on the human or animal body. One aspect of the invention is use of an 18FBAR compound as described herein in the manufacture of a medicament for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy).
One aspect of the invention is a method of therapeutic monitoring of a therapy for a disease or disorder in a subject undergoing said therapy which employs an 18FBAR compound as described herein. ln one embodiment, the method of therapeutic monitoring comprises the following steps:
(i) introducing the 18FBAR compound into the subject;
(ii) determining the presence and/or location and/or amount of 18FBAR compound in the subject;
(iii) correlating the result of the determination made in (ii) with effect and/or effectiveness and/or progress of the therapy.
The term "undergoing therapy" is intended to mean about to undergo the therapy, currently undergoing the therapy, or (recently) completed the therapy.
In one embodiment, the step of: (i) introducing the 18FBAR compound into the subject is the step of: (i) administering to the subject an effective amount of the 18FBAR compound (preferably as part of a pharmaceutically acceptable composition). In this context, the term "effective amount" pertains to that amount of the 18FBAR compound, or a material, composition or dosage form comprising the 18FBAR compound, which is effective for permitting some desired determination of the presence and/or location and/or amount of 18FBAR compound in the subject, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired regimen.
In one embodiment, the determination of the presence and/or location and/or amount of 18FBAR compound in the subject is by positron emission (e.g., PET) imaging.
Diseases and Disorders: Conditions Relating to Metals
In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals. In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates.
In one embodiment, the disease or disorder is Alzheimer's disease (AD); Parkinson's disease (PD); Huntington's disease (HD); amyotrophic lateral sclerosis (ALS);
Creutzfeldt-Jakob disease (CJD); multiple sclerosis (MS); Friedreich's ataxia; Wilson's disease; or Hallervorden-Spatz syndrome.
In one embodiment, the disease or disorder is Alzheimer's disease (AD).
In one embodiment, the disease or disorder is Parkinson's disease (PD). ln one embodiment, the disease or disorder is Huntington's disease (HD). Diseases and Disorders: Conditions Relating to Protein Aggregates
In one embodiment, the disease or disorder is a disease or disorder involving deposition of protein aggregates.
In one embodiment, the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates.
In one embodiment, the disease or disorder is an amyloidosis, a tauopathy,
a synucleinopathy, or a prion disease or disorder.
In one embodiment, the disease or disorder is an amyloidosis, for example: Alzheimer's disease (AD); Down's syndrome; hereditary cerebral haemorrhage with amyloidosis; Gerstmann-Straussler-Scheinker disease; fatal familial insomnia; hereditary cerebral hemorrhage with amyloidosis (Icelandic); familial dementia (also referred to as cerebral amyloidosis, British & Danish types); familial amyloid neuropathy; or Finnish type amyloidosis.
In one embodiment, the disease or disorder is a tauopathy, for example: Alzheimer's disease (AD); amyotrophic lateral sclerosis/parkinsonism-dementia complex; argyrophilic grain dementia; corticobasal degeneration; Creutzfeldt-Jakob disease (CJD); dementia pugilistica; diffuse neurofibrillary tangles with calcification; Down's syndrome;
frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP17);
Gerstmann-Straussler-Scheinker disease; Hallevorden-Spatz disease; inclusion-body myositis; multiple system atrophy; myotonic dystrophy; Niemann-Pick disease, type C; non-Guamanian motor neuron disease with neurofibrillary tangles; Pick's disease;
post-encephalitic parkinsonism; prion protein cerebral amyloid angiopathy; progressive supranuclear palsy; subacute sclerosing panencephalitis; tangle only dementia; tangle- predominant Alzheimer's disease. In one embodiment, the disease or disorder is a synucleinopathy, for example:
Parkinson's disease (PD); dementia with Lewy bodies (DLB); pure autonomic failure (PAF); multiple system atrophy (MSA); or Hallervorden-Spatz disease.
In one embodiment, the disease or disorder is prion disease or disorder, for example: Creutzfeldt-Jakob disease (CJD); variant Creutzfeldt-Jakob disease; Gerstmann- Straussler-Scheinker disease; Fatal familial insomnia; or Kuru (in humans) or scrapie; Bovine Spongiform Encephalopathy (BSE); transmissible mink encephalopathy; feline spongiform encephalopathy; ungulate spongiform encephalopathy; or chronic wasting disease (CWD) (in animals). In one embodiment, the disease or disorder is Alzheimer's disease (AD).
In one embodiment, the disease or disorder is Parkinson's disease (PD).
In one embodiment, the disease or disorder is Huntington's disease (HD).
Diseases and Disorders: Conditions Relating to GABAA
In one embodiment, the disease or disorder is a disease or disorder involving dis-regulation of a GABAA receptor.
In one embodiment, the disease or disorder is a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors.
In one embodiment, the disease or disorder is epilepsy, schizophrenia, a mood disorder (e.g., anxiety), autism, attention deficit hyperactivity disorder (ADHD), or a
neurodegenerative disorder (e.g., Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD)).
In one embodiment, the disease or disorder is epilepsy, schizophrenia, a mood disorder (e.g., anxiety), autism, or attention deficit hyperactivity disorder (ADHD).
In one embodiment, the disease or disorder is epilepsy, schizophrenia, or a mood disorder (e.g., anxiety). In one embodiment, the disease or disorder is epilepsy.
In one embodiment, the disease or disorder is schizophrenia.
In one embodiment, the disease or disorder is a mood disorder (e.g., anxiety).
In one embodiment, the disease or disorder is anxiety.
Diseases and Disorders: Conditions Relating to Metal Overdose/Poisoning In one embodiment, the disease or disorder is metal overdose or metal poisoning.
In one embodiment, the disease or disorder is metal overdose. ln one embodiment, the disease or disorder is metal poisoning.
In one embodiment, the metal is iron (e.g., iron overdose).
In one embodiment, the metal is lead (e.g., lead poisoning).
In one embodiment, the metal is mercury (e.g., mercury poisoning).
In one embodiment, the metal is cadmium (e.g., cadmium poisoning).
Diseases and Disorders: Conditions Relating to Metal-Induced Leakiness of the
Blood-Brain Barrier
There is evidence that metals cause leakiness of the blood-brain barrier (which is implicated for example in multiple sclerosis (MS) and Parkinson's disease (PD)) and increased access of metals to the brain. See, for example, Won et al., 201 1 . In one embodiment, the disease or disorder is a disease or disorder associated with metal-induced leakiness of the blood-brain barrier.
In one embodiment, the disease or disorder is metal-induced leakiness of the blood-brain barrier.
In one embodiment, the disease or disorder is multiple sclerosis (MS) or Parkinson's disease (PD).
In one embodiment, the disease or disorder is multiple sclerosis (MS).
In one embodiment, the disease or disorder is Parkinson's disease (PD).
Combinations with Other Methods
The positron emission imaging methods described herein may be combined with other diagnostic and/or imaging methods. For example, positron emission imaging methods described herein may be combined with x-ray computed tomography (CT) methods to provide improved diagnosis, prognosis, therapeutic monitoring, etc.
Other Uses
The 18FBAR compounds described herein may also be used as part of an in vitro assay, for example, in order to determine whether if a candidate 18FBAR compound binds to a particular protein aggregate, etc.
The 18FBAR compounds described herein may also be used as a standard, for example, in an assay, in order to identify other compounds, other PET imaging agents, etc. Kits
One aspect of the invention is a kit comprising (a) an 18FBAR compound as described herein, or a composition comprising an 18FBAR compound as described herein, e.g., preferably provided in a suitable container and/or with suitable packaging; and (b) instructions for use, e.g., written instructions on how to administer the compound or composition. The written instructions may also instructions regarding subsequent positron emission (e.g., PET) imaging and/or a list of indications for which the compound or composition may be used in, e.g., a method of diagnosis, prognosis, therapeutic monitoring, etc.
Routes of Administration
The 18FBAR compound or pharmaceutical composition comprising the 18FBAR compound may be administered to a subject by any convenient and appropriate route of
administration. A preferred route of administration parenteral, for example, by injection, including subcutaneous, intradermal, intramuscular, intravenous, intraarterial, intracardiac, intrathecal, intraspinal, intracapsular, subcapsular, intraorbital, intraperitoneal, intratracheal, subcuticular, intraarticular, subarachnoid, and intrasternal. The Subiect/Patient
The subject/patient may be a mammal, a rodent (e.g., a guinea pig, a hamster, a rat, a mouse), murine (e.g., a mouse), a lagomorph (e.g., a rabbit), avian (e.g., a bird), canine (e.g., a dog), feline (e.g., a cat), equine (e.g., a horse), porcine (e.g., a pig), ovine (e.g., a sheep), bovine (e.g., a cow), a primate, simian (e.g., a monkey or ape), a monkey
(e.g., marmoset, baboon), an ape (e.g., gorilla, chimpanzee, orangutang, gibbon), or a human.
Furthermore, the subject/patient may be any of its forms of development, for example, a foetus.
In one preferred embodiment, the subject/patient is a human. Formulations
While it is possible for the 18FBAR compound to be administered alone, it is preferable to present it as a pharmaceutical formulation (e.g., composition, preparation, medicament) comprising at least one 18FBAR compound, as described herein, together with one or more other pharmaceutically acceptable ingredients well known to those skilled in the art, including, but not limited to, pharmaceutically acceptable carriers, diluents, excipients, adjuvants, fillers, buffers, preservatives, anti-oxidants, lubricants, stabilisers, solubilisers, surfactants (e.g., wetting agents), masking agents, colouring agents, flavouring agents, and sweetening agents. The formulation may further comprise other active agents, for example, other therapeutic or prophylactic agents.
Thus, the present invention further provides pharmaceutical compositions, as defined above, and methods of making a pharmaceutical composition comprising admixing at least one 18FBAR compound, as described herein, together with one or more other pharmaceutically acceptable ingredients well known to those skilled in the art, e.g., carriers, diluents, excipients, etc. If formulated as discrete units (e.g., ampoules, etc.), each unit contains a predetermined amount (dosage) of the compound. The term "pharmaceutically acceptable," as used herein, pertains to compounds, ingredients, materials, compositions, dosage forms, etc., which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of the subject in question (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, diluent, excipient, etc. must also be "acceptable" in the sense of being compatible with the other ingredients of the formulation.
Suitable carriers, diluents, excipients, etc. can be found in standard pharmaceutical texts, for example, Remington's Pharmaceutical Sciences, 18th edition, Mack Publishing Company, Easton, Pa., 1990; and Handbook of Pharmaceutical Excipients, 5th edition, 2005.
The formulations may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the compound with a carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the compound with carriers (e.g., liquid carriers, finely divided solid carrier, etc.), and then shaping the product, if necessary. A preferred formulation is in the form of a liquid, solution (e.g., aqueous, non-aqueous), suspension (e.g., aqueous, non-aqueous), or emulsion (e.g., oil-in-water, water-in-oil). The compound may be dissolved in, suspended in, or admixed with one or more other pharmaceutically acceptable ingredients. The compound may be presented in a liposome or other microparticulate which is designed to target the compound, for example, to one or more organs.
Formulations suitable for parenteral administration (e.g., by injection), include aqueous or non-aqueous, isotonic, pyrogen-free, sterile liquids (e.g., solutions, suspensions), in which the compound is dissolved, suspended, or otherwise provided (e.g., in a liposome or other microparticulate). Such liquids may additional contain other pharmaceutically acceptable ingredients, such as anti-oxidants, buffers, preservatives, stabilisers, bacteriostats, suspending agents, thickening agents, and solutes which render the formulation isotonic with the blood (or other relevant bodily fluid) of the intended recipient. Examples of excipients include, for example, water, alcohols, polyols, glycerol, vegetable oils, and the like. Examples of suitable isotonic carriers for use in such formulations include Sodium Chloride Injection, Ringer's Solution, or Lactated Ringer's Injection.
Typically, the concentration of the compound in the liquid is from about 1 ng/mL to about 10 μg/mL. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored under suitable conditions prior to use.
Dosage
It will be appreciated by one of skill in the art that appropriate dosages of the 18FBAR compounds, and compositions comprising the 18FBAR compounds, can vary from subject to subject. Determining the optimal dosage will generally involve the balancing of the level of benefit effect (e.g., diagnosis, prognosis, therapeutic monitoring) against any risk or deleterious side effects. The selected dosage level will depend on a variety of factors including, but not limited to, the binding affinity of the particular 18FBAR compound, the route of administration, the time of administration, the rate of excretion of the 18FBAR compound, the duration of the procedure (e.g., imaging process), other drugs,
compounds, and/or materials used in combination, the severity of the condition under investigation, and the species, sex, age, weight, condition, general health, and prior medical history of the subject. The amount of 18FBAR compound and route of
administration will ultimately be at the discretion of the physician, veterinarian, or clinician, although generally the dosage will be selected to achieve local concentrations at the site of action which achieve the desired effect without causing substantial harmful or deleterious side-effects. Administration can be effected in one dose, continuously or intermittently (e.g., in divided doses at appropriate intervals) throughout the course of the procedure. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used, the purpose of the procedure, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician, veterinarian, or clinician.
In general, a suitable dose of the 18FBAR compound is in the range of about 0.1 μg to about 5 μg for a single positron emission scan of an adult human subject. Typically, the normal dose of the 18FBAR compound for a single positron emission scan of an adult human subject, in terms of activity, is about 140 MBq (5 mSv). Where the compound is a salt, a solvate, a chemically-protected form, or the like, the amount administered is calculated on the basis of the parent compound and so the actual weight to be used is increased proportionately.
EXAMPLES
The following examples are provided solely to illustrate the present invention. They not intended to limit the scope of the invention, as described herein.
Chemical Synthesis
Synthesis 1
Diethyl 2-(6-(benzyloxy)hexyl)-2-ethylmalonate (1 )
Figure imgf000076_0001
To a solution of diethyl 2-ethylmalonate (99%, 1 .9 ml_, 10.0 mmol, 1 eq) in dry DMF (15 ml_), sodium hydride (60% dispersion in mineral oil, 490 mg, 12.3 mmol, 1 .2 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1.5 hours. Then ((6-bromohexyloxy)methyl)benzene (97%, 2.9 ml_, 12.5 mmol, 1.2 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for 3.5 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (CH2CI2) to give 3.444 g of the title compound (91 %) as a yellow oil.
Rf = 0.34 (CH2CI2). 1 H NMR (400 MHz, CDCI3) δ: 7.30 - 7.18 (m, 5H), 4.42 (s, 2H), 4.10 (q, J = 7.1 Hz, 4H), 3.38 (t, J = 6.6 Hz, 2H), 1.89 - 1.74 (m, 4H), 1.59 - 1.48 (m, 2H), 1.38 - 1 .25 (m, 4H), 1 .20 (t, J = 7.1 Hz, 6H), 1 .16 - 1 .06 (m, 2H), 0.74 (t, J = 7.6 Hz, 3H). 13C NMR (100 MHz, CDCI3) δ: 172.2, 139.0, 128.7, 127.9, 127.8, 73.2, 70.7, 61.2, 58.2, 31.9, 30.1 , 30.0, 26.3, 25.5, 24.2, 14.5, 8.8. ESI MS m/z: calcd. for C22H3505 [/W+H]+ 379.2, [M+UaY C22H3405 Na 401.2, found: 379.2, 401 .2. Synthesis 2
5-(6-(Benzyloxy)hexyl)-5-ethylpyrimidine-2,4,6(1 H,3H,5H)-trione (2)
Figure imgf000077_0001
To a suspension of urea (99%, 2.481 g, 40.9 mmol, 10 eq) in dry DMF (12.5 mL), sodium hydride (60% dispersion in mineral oil, 665 mg, 16.6 mmol, 4 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1 hour. Then a solution of diethyl 2-(6-(benzyloxy)hexyl)-2-ethylmalonate (1 ) (1.567 g, 4.1 mmol, 1 eq) in dry DMF (2 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 2 hours. The reaction was quenched with a cold saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether.
The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 1 :1 ) to give 1 .240 g of the title compound (87%) as a white solid. Rf = 0.75 (n-Hex/EtOAc 1 :1 ). M.p. 65-67°C. 1H NMR (400 MHz, CDCI3) δ: 9.76 (s, 2H), 7.39 - 7.19 (m, 5H), 4.50 (s, 2H), 3.43 (t, J = 6.6 Hz, 2H), 2.1 1 - 1.91 (m, 4H), 1 .64 - 1.51 (m, 2H), 1 .38 - 1 .14 (m, 6H), 0.86 (t, J = 7.4 Hz, 3H). 13C NMR (100 MHz, CDCI3) δ: 173.2, 149.6, 138.8, 128.6, 128.0, 127.8, 73.1 , 70.5, 57.7, 39.0, 32.8, 29.8, 29.6, 26.1 , 25.4, 9.8. ESI MS m/z: calcd. for Ci9H27N204 [/W+H]+ 347.2, [/W+Na]+ Ci9H26N2Na04 369.2, found: 347.2, 369.1 .
Synthesis 3
5-Ethyl-5-(6-hydroxyhexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (3)
Figure imgf000077_0002
A mixture of 5-(6-(benzyloxy)hexyl)-5-ethylpyrimidine-2, 4,6(1 H,3H,5H)-trione (2) (1.61 1 g, 4.6 mmol) and 24% wt of 20% Pd(OH)2/C (0.393 g) in MeOH (40 mL) was stirred at room temperature under H2 atmosphere. After 17 hours, the mixture was filtered through Celite, washing the dark solid with MeOH. The solvent was removed in vacuo to give 1.183 g of the title compound (>98%) as a white solid. The product was used without further purification.
Rf = 0.30 (CH2CI2/EtOAc 1 :1 ). M.p. 90-92°C. 1 H NMR (400 MHz, CDCI3) δ: 9.09 (s, 2H), 3.63 (t, J = 6.5 Hz, 2H), 2.12 - 1.87 (m, 4H), 1 .61 - 1.44 (m, 2H), 1.39 - 1.12 (m, 7H), 0.88 (t, J = 7.4 Hz, 3H). 13C NMR (100 MHz, CDCI3) δ: 173.3, 149.6, 63.0, 57.7, 38.9, 32.9, 32.6, 29.4, 25.6, 25.4, 9.8. ES/ MS m/z: calcd. for C12H21 N2O4 [/W+H]+ 257.1 , [/W+Na]+ Ci2H2oN2Na04 279.1 , found: 257.1 , 279.1 .
Synthesis 4
5-Ethyl-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (4)
Figure imgf000078_0001
Route A: To a solution of 5-ethyl-5-(6-hydroxyhexyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (3) (443 mg, 1 .7 mmol, 1 eq) in dry CHCI3 (17 ml_), diethylaminosulfur trifluoride (DAST) (99%, 458 μΙ_, 3.5 mmol, 2 eq) was added at -4°C. The reaction mixture was stirred at this temperature for 2 hours under nitrogen atmosphere. Water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (CH2CI2/EtOAc 9:1 ) to afford 233 mg of the title compound as a white solid (53%). Rf = 0.25 (CH2CI2/EtOAc 9:1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 6.8 minutes. 1 H NMR (400 MHz, CDCI3) δ: 9.31-9.13 (s, 2H), 4.39 (dt, J = 47.3, 6.1 Hz, 2H), 2.19-1.88 (m, 4H), 1 .74-1.52 (m, 2H), 1.46-1 .12 (m, 6H), 0.98-0.79 (t, J = 7.4 Hz,
3H). ldC NMR (100 MHz, CDCI3) δ: 173.3, 149.8, 84.2 (d, J = 164.3 Hz), 57.7, 38.7, 32.9, 30.4 (d, J = 19.6 Hz), 29.3, 25.4, 25.1 (d, J = 5.3 Hz), 9.7. 19F NMR (564 MHz, CDCI3) δ: -217.96-218.34 (m). ES/ MS m/z: calcd. for C12H2oFN203 [/W+H+] 259.1 , [/W+Na+]
Ci2H19FN2Na03 281 .1 , found: 259.1 , 281.1 .
Route B (yield optimized): To a solution of 5-ethyl-5-(6-hydroxyhexyl)pyrimidine- 2,4,6(1 H,3H,5H)-trione (3) (250 mg, 1.0 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (8 mL) diethylaminosulfur trifluoride (DAST) (99%, 260 μΙ_, 2.0 mmol, 2 eq) was added at -78°C. The reaction mixture was stirred at this temperature for 15 minutes under nitrogen atmosphere and then it was allowed to warm to room temperature. After 4.5 hours water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n- Hex/EtOAc 4:1 to n-Hex/EtOAc 3:1 ) to afford 181 mg of the title compound as a white solid (72%). Rf = 0.14 (n-Hex/EtOAc 4:1 ). M.p. 131 -132°C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 6.8 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1 H NMR (400 MHz, CDCI3) δ: 9.22 (s, 2H), 4.39 (dt, J = 47.3, 6.1 Hz, 2H), 2.19 - 1 .88 (m, 4H), 1 .74 - 1 .52 (m, 2H), 1.46 - 1 .12 (m, 6H), 0.98 - 0.79 (t, J = 7.4 Hz, 3H). 13C NMR (100 MHz, CDCI3) δ: 173.3, 149.8, 84.2 (d, J = 164.3 Hz), 57.7, 38.7, 32.9, 30.4 (d, J = 19.6 Hz), 29.3, 25.4, 25.1 (d, J = 5.3 Hz), 9.7. 19F NMR (564 MHz, CDCI3) δ: -217.96 - 218.34 (m). ES/ MS m/z: calcd. for C12H20FN2O3 [/W+H]+ 259.1 , [/W+Na]+ C12H19FN2Na03 281.1 , found: 259.1 , 281 .1 .
Synthesis 5
6-(5-Ethyl-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (5)
Figure imgf000079_0001
Method A: To a suspension of 5-ethyl-5-(6-hydroxyhexyl)pyrimidine-2, 4,6(1 H,3H,5H)- trione (3) (507 mg, 2.0 mmol, 1 eq) in dry CHCI3 (15 mL) dry pyridine (320 μί, 4.0 mmol, 2 eq) was added. The mixture was cooled in an ice bath and p-toluenesulfonyl chloride (98%, 1 .163 g, 6.0 mmol, 3 eq) was added. The reaction mixture was stirred at room temperature under nitrogen atmosphere for 4 days. Diethyl ether and water were added. The layers were separated and the aqueous phase was extracted with diethyl ether. The combined organic extracts were washed with 2 N HCI, 5% NaHC03, H20 and then dried over anhydrous Na2S04. The solvent was removed in vacuo and the residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 3:2) to afford 691 mg of the title compound as a white solid (85%).
Rf = 0.28 (n-Hex/EtOAc 3:2). M.p. 89-90°C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 1 1 .1 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CDCI3) δ: 8.57 (s, 2H), 7.77 (d, J = 8.3 Hz, 2H), 7.34 (d, J = 8.5 Hz, 2H), 3.98 (t, J = 6.4 Hz, 2H), 2.45 (s, 3H), 2.02 (q, J = 7.4 Hz, 2H), 1 .97 - 1 .88 (m, 2H), 1 .64 - 1.54 (m, 2H), 1 .31 - 1 .1 1 (m, 6H), 0.88 (t, J = 7.4 Hz, 3H). 13C NMR (100 MHz, CDCI3) δ: 173.2, 149.7, 145.0, 133.3, 130.1 , 128.1 , 70.6, 57.5, 38.5, 32.9, 29.0, 28.9, 25.2, 21 .9, 9.7. ESI MS m/z: calcd. for C19H27N2O6S [/W+H]+ 41 1.2, [/W+Na]+ Ci9H26N2Na06S 433.1 , found: 41 1 .1 , 433.1 .
Synthesis 6
5-Ethyl-5-(6-[18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (6)
Figure imgf000080_0001
Method B: [18F]Fluoride was produced by CTI RDS-1 1 1 cyclotron (CTI/Siemens) via the 180(p,n)18F nuclear reaction by bombardment of isotopically enriched [180]H20 target and passed through a Chromafix® 30-PS-HCO3 cartridge (Macherey Nagel) as an aqueous solution in 180-enriched water. [18F]F" was eluted from the cartridge with 0.5 mL of K2C03 solution in water (6 mg/mL) into a reaction vessel in the hot cell. Then a solution of Kryptofix® 222 (15 mg) in dry CH3CN (1 mL) was added. Water was removed by azeotropic distillation with acetonitrile under stream of helium at 85°C. A solution of tosyl precursor 6-(5-ethyl-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (5) (15 mg) in dry CH3CN (1 mL) was added to the to the reaction vessel containing the dried [K222] / [18F]F complex (1 1 GBq). After heating at 100°C for 15 minutes, the reaction mixture was cooled to room temperature. Then a solution of 1 N HCI (150 μί) in dry CH3CN (350 μΙ_) was added, and the mixture was passed through two pre-conditioned Sep-Pak® Light Alumina N cartridges (Waters) in order to remove the unreacted fluoride. The cartridges were pre-conditioned with 10% 1 N HCI in CH3CN and dried. The product was purified by semi-preparative HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 10.0 mm (L x ID), volume injected 350 μί (623 MBq), flow rate 4 mL/min, solvent A: H20, solvent B: CH3CN, gradient: 40%-95% B in 15 minutes. A simultaneous detection by UV and radioactivity monitors was performed to isolate the desired product. The retention time of title compound was 8.08 minutes. The solvent was removed in vacuo.
The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-ethyl-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr\one (4) on the same column. The product was solubilised in CH3CN and analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί (0.44 MBq), flow rate 1 mL/min, solvent A: H20, solvent B: CH3CN, gradient: 40%- 95% B in 15 minutes. The retention time in the UV-chromatogram was identical to the retention time of 5-ethyl-5-(6-[18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (6) in the radioactivity chromatogram.
Figure imgf000081_0001
To a solution of diethyl 2-phenylmalonate (98%, 1.9 mL, 8.6 mmol, 1 eq) in dry DMF (15 mL), sodium hydride (60% dispersion in mineral oil, 420 mg, 10.5 mmol, 1.2 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1 hour. Then ((6-bromohexyloxy)methyl)benzene (97%, 2.5 mL, 10.8 mmol, 1.2 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for 2 days. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9:1 ) to give 1.471 g of the title compound (40%) as a colourless oil.
Rf = 0.30 (n-Hex/EtOAc 9:1 ). 1 H NMR (400 MHz, CDCI3) δ: 7.39 - 7.31 (m, 2H), 7.31 - 7.12 (m, 8H), 4.40 (s, 2H), 4.20 - 4.06 (m, 4H), 3.35 (t, J = 6.6 Hz, 2H), 2.26 - 2.16 (m, 2H), 1 .54 - 1 .45 (m, 2H), 1.33 - 1 .22 (m, 4H), 1.22 - 1.07 (m, 2H), 1 .15 (t, J = 7.1 Hz, 6H). 13C NMR (100 MHz, CDCI3) δ: 171 .0, 138.9, 137.4, 128.5, 128.3, 127.8, 127.7, 127.6, 73.1 , 70.6, 62.8, 61 .6, 35.9, 30.0, 29.9, 26.1 , 24.8, 14.2. ESI MS m/z: calcd. for C26H3505 [/W+H]+ 427.2, [M+Haf C26H34Na05 449.2, found: 427.3, 449.3.
Synthesis 8
5-(6-(Benzyloxy)hexyl)-5-phenylpyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (8)
Figure imgf000082_0001
To a suspension of urea (99%, 217 mg, 3.6 mmol, 10 eq) in dry DMF (1 mL), sodium hydride (60% dispersion in mineral oil, 98 mg, 2.4 mmol, 7 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 2 hours. Then a solution of diethyl 2-(6-(benzyloxy)hexyl)-2-phenylmalonate (7) (148 mg, 0.35 mmol, 1 eq) in dry DMF (0.5 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 2.5 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7:3) to give 48 mg of the title compound (35%) as a white solid. Rf = 0.36 (n-Hex/EtOAc 7:3). M.p. 103-105°C. 1H NMR (400 MHz, CDCI3) δ: 9.12 (s,
2H), 7.42 - 7.03 (m, 10H), 4.42 (s, 2H), 3.37 (t, J = 6.6 Hz, 2H), 2.39 - 2.26 (m, 2H), 1 .57- 1.46 (m, 2H), 1 .42 - 1 .07 (m, 6H). 13C NMR (100 MHz, CDCI3) δ: 171 .3, 149.5, 138.8, 137.4, 129.5, 129.0, 128.6, 128.0, 127.8, 126.5, 73.1 , 70.5, 61 .0, 36.8, 29.8, 29.7, 26.0, 25.9. ESI MS m/z: calcd. for C23H27N204 [/W+H]+ 395.2, [/W+Na]+ C23H26N2Na04 417.2, found: 395.2, 417.2. Svnthesis 9
5-(6-Hydroxyhexyl)-5-phenylpyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (9)
Figure imgf000083_0001
A mixture of 5-(6-(benzyloxy)hexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tr\one (8)
(58 mg, 0.15 mmol) and 20% wt of 20% Pd(OH)2/C (12 mg) in MeOH (3.5 mL) was stirred at room temperature under H2 atmosphere. After 15 hours, the mixture was filtered through Celite, and the dark solid was washed with MeOH. The solvent was removed in vacuo and the residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 3:7) to afford 42 mg of the title compound as a white solid (93%).
Rf = 0.45 (n-Hex/EtOAc 3:7). M.p. 158-160°C. 1 H NMR (400 MHz, CD3OD) δ: 7.46-7.30 (m, 5H), 3.57 (t, J = 6.6 Hz, 2H), 2.42 - 2.36 (m, 2H), 1.60-1 .50 (m, 2H), 1.46 - 1.29 (m, 6H). 13C NMR (100 MHz, CD3OD) δ: 174.2, 152.1 , 140.6, 130.9, 130.3, 128.1 , 63.7, 62.2, 38.0, 34.3, 31.4, 27.4, 27.3. ESI MS m/z: calcd. for C16H21N204 [M+H]+ 305.1 , [M+Ua]+ Ci6H20N2NaO4 327.1 , found: 305.2, 327.1 .
Synthesis 10
5-(6-Fluorohexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-trione (10)
Figure imgf000083_0002
To a solution of 5-(6-hydroxyhexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tnor\e (9)
(91 mg, 0.30 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (3 mL), diethylaminosulfur trifluoride (DAST) (99%, 120 μΙ_, 146 mg, 0.9 mmol, 3 eq) in a dry ice was added. The reaction mixture was stirred at -78°C for 15 minutes and then warmed up to room temperature. The reaction was stirred for another 3 hours under nitrogen atmosphere. Water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7:3) to afford 64 mg of the title compound as a white solid (70%).
Rf = 0.32 (n-Hex/EtOAc 7:3). M.p. 135-137°C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 9.4 minutes. The purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1 H NMR (400 MHz, CD3OD) δ: 7.45 - 7.31 (m, 5H), 4.42 (dt, J = 47.5, 6.1 Hz, 2H), 2.45 - 2.32 (m, 2H), 1 .77 - 1.60 (m, 2H), 1.49 - 1 .29 (m, 6H). 13C NMR (100 MHz, CD3OD) δ: 174.2, 152.1 , 140.6, 130.9, 130.3, 128.1 , 85.6 (d, J = 163.7 Hz), 62.3, 37.9, 32.2 (d, J = 19.5 Hz), 31 .2, 27.3, 26.7 (d, J = 5.4 Hz). 19F NMR (564 MHz, CD3OD) δ: -219.77-220.08 (m). ESI MS m/z: calcd. for Ci6H20FN2O3 [M+H]+ 307.1 , [M+Ua]+ Ci6H19FN2Na03 329.1 , found: 307.2, 329.1 .
Synthesis 1 1
6-(2,4,6-Trioxo-5-phenylhexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (11 )
Figure imgf000084_0001
Using a method analogous to Method A, with 5-(6-hydroxyhexyl)-5-phenylpyrimidine- 2,4,6(1 /-/,3/-/,5/-/)-trione (9), the title compound was obtained as a white solid (65%).
Rf = 0.27 (n-Hex/EtOAc 3:2). M.p. 52-54°C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 12.6 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz,CDCI3) δ 8.85 (s, 2H), 7.85 - 7.70 (d, 2H), 7.45 - 7.27 (m, 7H), 3.99 (t, J = 6.4 Hz, 2H), 2.43 (s, 3H), 2.39 - 2.29 (m, 2H), 1.66 - 1 .56 (m, 2H), 1.34 - 1 .23 (m, 6H); 13C NMR (100 MHz, CDCI3) δ 170.9, 149.1 , 145.0, 137.2, 133.4, 130.2, 129.6, 129.2, 128.2, 126.4, 70.7, 61 .1 , 36.6, 29.2, 28.9, 25.8, 25.2, 21.9; ES/ MS m/z: calcd. for C23H27N206S [M+H]+ 459.2, C23H26N2Na06S[/W+Na]+ 481.1 , found: 459.1 , 481 .1. Svnthesis 12
5-(6-[18F]Fluorohexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-trione (12)
Figure imgf000085_0001
Using a method analogous to Method B, with 6-(2,4,6-trioxo-5-phenylhexahydropyrimidin- 5-yl)hexyl 4-methylbenzenesulfonate (1 1 ), the title compound was obtained.
The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-(6-fluorohexyl)-5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tr\one (10) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x I D), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time in the UV-chromatogram was identical to the retention time of 5-(6-[18F]fluorohexyl)- 5-phenylpyrimidine-2,4,6(1 H,3H,5H)-tr\one (12) in the radioactivity chromatogram.
Synthesis 13
Diethyl 2-benzyl-2-(6-(benzyloxy)hexyl)malonate (13)
Figure imgf000085_0002
To a solution of diethyl 2-benzylmalonate (97%, 1 .9 mL, 7.8 mmol, 1 eq) in dry DMF (15 mL), sodium hydride (60% dispersion in mineral oil, 387 mg, 9.7 mmol, 1 .2 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 45 minutes. Then ((6-bromohexyloxy)methyl)benzene (97%, 2.0 mL, 8.6 mmol, 1 .1 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for 24 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9:1 ) to give 3.165 g of 13 (92%) as a pale yellow oil.
Rf = 0.31 (n-Hex/EtOAc 9:1 ). 1 H NMR (400 MHz, CDCI3) δ 7.30 - 7.08 (m, 8H), 7.01 - 6.96 (m, 2H), 4.42 (s, 2H), 4.14 - 4.04 (m, 4H), 3.37 (t, J = 6.6 Hz, 2H), 3.15 (s, 2H), 1 .73 - 1 .64 (m, 2H), 1 .55 - 1 .48 (m, 2H), 1.34 - 1.19 (m, 6H), 1.15 (t, J = 7.1 Hz, 6H);
13C NMR (100 MHz, CDCI3) δ 171 .6, 138.9, 136.6, 130.1 , 128.6, 128.5, 127.9, 127.8, 127.1 , 73.2, 70.6, 61.4, 59.1 , 38.3, 32.0, 30.0, 29.9, 26.3, 24.4, 14.4; ESI MS m/z: calcd. for C27H3705 [/W+H]+ 441.3, C27H36Na05 [/W+Na]+ 463.2, found: 441 .2, 463.2.
Synthesis 14
5-Benzyl-5-(6-(benzyloxy)hexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (14)
Figure imgf000086_0001
To a suspension of urea (99%, 1.106 g, 18.2 mmol, 10 eq) in dry DMF (5 mL), sodium hydride (60% dispersion in mineral oil, 289 mg, 7.2 mmol, 4 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1 hour. Then a solution of 13 (803 mg, 1.8 mmol, 1 eq) in dry DMF (3 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 5 hours. The reaction was quenched with a saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous
Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7:3) to give 589 mg of 14 (80%) as a white solid. Rf = 0.35 (n-Hex/EtOAc 7:3). M. p. 140-141 °C. 1H NMR (400 MHz, CDCI3) δ 8.33 (br s, 2H), 7.34 - 6.97 (m, 10H), 4.42 (s, 2H), 3.37 (t, J = 6.5 Hz, 2H), 3.18 (s, 2H), 2.10 - 2.02 (m, 2H), 1 .54 - 1.46 (m, 2H), 1.32 - 1.20 (m, 4H), 1.18 - 1.08 (m, 2H); 13C NMR (100 MHz, CDCI3) δ 172.4, 148.4, 138.9, 134.8, 129.7, 129.1 , 128.7, 128.2, 128.0, 127.9, 73.2, 70.5, 59.1 , 45.3, 39.2, 29.8, 29.6, 26.1 , 25.4; ESI MS m/z: calcd. for C24H29N204 [M+H]+ 409.2, C24H28N2Na04 [/W+Na]+ 431 .2, found: 409.2, 431.2. Synthesis 15
5-Benzyl-5-(6-hydroxyhexyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (15)
Figure imgf000087_0001
A mixture of 14 (450 mg, 1.1 mmol) and 20% wt of 20% Pd(OH)2/C (1 14 mg) in MeOH (20 mL) was stirred at room temperature under H2 atmosphere. After 17 hours the mixture was filtered through Celite and the bed was washed with MeOH and then with EtOAc. The solvent was removed in vacuo and the residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 2:3 to n-Hex/EtOAc 3:7) to afford 163 mg of 15 as a white solid (46%).
Rf = 0.55 (n-Hex/EtOAc 3:7). M.p. 162-164°C. 1H NMR (400 MHz, CD3OD) δ 7.31 - 6.80 (m, 5H), 3.43 (t, J = 6.6 Hz, 2H), 3.08 (s, 2H), 2.04 - 1.93 (m, 2H), 1 .45 - 1.35 (m, 2H), 1.28 - 1 .18 (m, 4H), 1.17 - 1 .07 (m, 2H); 13C NMR (100 MHz, CD3OD) δ 175.4, 151.7, 137.3, 131 .3, 130.4, 129.4, 63.7, 60.2, 47.2, 40.4, 34.2, 31.3, 27.3, 27.0; ES/ MS m/z: calcd. for Ci7H23N204 [/W+H]+ 319.2, Ci7H22N2Na04[/W+Na]+ 341 .1 , found: 319.1 , 341.1.
Synthesis 16
5-Benzyl-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (16)
Figure imgf000087_0002
To a solution of 15 (120 mg, 0.38 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (3 mL) diethylaminosulfur trifluoride (DAST) (99%, 100 μΙ_, 0.75 mmol, 2 eq) was added at -78°C. The reaction mixture was stirred under nitrogen atmosphere at this temperature for 10 minutes and then warmed to room temperature. The reaction was stirred at room temperature for another 2.5 hours, cooled again to -78°C and a second portion of DAST (99%, 50 μΙ_, 0.38 mmol, 1 eq) was added. The reaction mixture was stirred at this temperature for 10 minutes and then it was warmed to room temperature and stirred for 1.5 hours. Water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7:3) to afford 73 mg of 16 as a white solid (60%).
Rf = 0.46 (n-Hex/EtOAc 7:3). M.p. 149-151 °C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 9.9 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1 H NMR (400 MHz, CDCI3) δ 8.48 (s, 2H), 7.25 - 7.15 (m, 3H), 7.13 - 7.03 (m, 2H), 4.42 (dt, J = 47.3, 6.1 Hz, 2H), 3.27 (s, 2H), 2.23 - 2.08 (m, 2H), 1.73 - 1 .57 (m, 2H), 1 .46 - 1.30 (m, 4H), 1 .29 - 1 .18 (m, 2H); 13C NMR (100 MHz, CDCI3) δ 172.5, 148.5, 134.7, 129.7, 129.1 , 128.2, 84.2 (d, J = 164.5 Hz), 59.1 , 45.4, 39.0, 30.5 (d, J = 19.6 Hz), 29.3, 25.4, 25.1 (d, J = 5.3 Hz); 19F NMR (564 MHz, CDCI3) δ -218.05 - -218.56 (m); ESI MS m/z: calcd. for Ci7H22FN203 [M+H]+ 321.2, Ci7H21FN2Na03 [M+Ua] + 343.3, found: 321.2, 343.1 .
Synthesis 17
6-(5-Benzyl-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (17)
Figure imgf000088_0001
Using a method analogous to Method A, with 5-benzyl-5-(6-hydroxyhexyl)pyrimidine- 2,4,6(1 /-/,3/-/,5H)-trione (15), the title compound was obtained as a white solid (41 %). Rf = 0.20 (n-Hex/EtOAc 7:3). M.p. 50-52°C. The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time was 13.5 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CDCI3) δ 8.33 (br s, 2H), 7.78 (d, J = 8.3 Hz, 2H), 7.35 (d, J = 8.0 Hz, 2H), 7.24 - 7.17 (m, 3H), 7.1 1 - 7.02 (m, 2H), 3.99 (t, J = 6.4 Hz, 2H), 3.24 (s, 2H), 2.45 (s, 3H), 2.17 - 2.03 (m, 2H), 1 .66 - 1 .55 (m, 2H), 1.31 - 1.13 (m, 6H); 13C NMR (100 MHz, CDCI3) δ 172.3, 148.3, 145.0, 134.6, 133.4, 130.2, 129.7, 129.1 , 128.2, 70.6, 59.0, 45.5, 38.9, 29.1 , 29.0, 25.3, 22.0; ESI MS m/z: calcd. for C24H29N206S [/W+H]+ 473.2, C24H28N2Na06S [/W+Na]+ 495.2, found: 473.2, 495.1.
Synthesis 18
5-Benzyl-5-(6-[18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (18)
Figure imgf000089_0001
Using a method analogous to Method B, with 6-(5-benzyl-2,4,6-trioxohexahydropyrimidin- 5-yl)hexyl 4-methylbenzenesulfonate (17), the title compound was obtained. The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-benzyl-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr\one (16) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20 + 0.1 % TFA, solvent B: CH3CN + 0.1 % TFA, method: 45% B for 3 minutes, linear gradient to 100% B in 15 minutes. The retention time in the UV-chromatogram was identical to the retention time of 5-benzyl-5-(6- [18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr\one (18) in the radioactivity chromatogram.
Synthesis 19
Diethyl 2-(cyclohexylmethyl)malonate (19)
Figure imgf000089_0002
To a solution of diethylmalonate (99%, 1.7 mL, 1 1.1 mmol, 1 eq) in dry DMF (15 mL), sodium hydride (60% dispersion in mineral oil, 484 mg, 12.1 mmol, 1 .1 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1.5 hours. Then (bromomethyl)cyclohexane (99%, 1.9 mL, 13.5 mmol, 1.2 eq) was added. After 4 hours under stirring at room temperature a second portion of (bromomethyl)cyclohexane (99%, 190 μί, 1.3 mmol, 0.2 eq) was added and the reaction mixture was stirred again for 17 hours at room temperature. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9.5:0.5) to give 1.580 g of 19 (56%) as a colourless oil. Rf = 0.30 (n-Hex/EtOAc 9.5:0.5). 1H NMR (400 MHz, CDCI3) δ 4.19 (q, J = 7.1 Hz, 4H), 3.44 (t, J = 7.7 Hz, 1 H), 1.79 (t, J = 7.4 Hz, 2H), 1 .76 - 1.52 (m, 5H), 1.26 (t, J = 7.1 Hz, 6H), 1 .24 - 1 .06 (m, 4H), 0.98 - 0.82 (m, 2H); 13C NMR (100 MHz, CDCI3) δ 169.9, 61.3, 49.8, 36.2, 35.7, 33.0, 26.5, 26.2, 14.2; ESI MS m/z: calcd. for Ci4H2504 [/W+H]+ 257.2, Ci4H24Na04 [/W+Na]+ 279.2, found: 257.2, 279.2.
Synthesis 20
Diethyl 2-(6-(benzyloxy)hexyl)-2-(cyclohexylmethyl)malonate (20)
Figure imgf000090_0001
To a solution of diethyl 2-(cyclohexylmethyl)malonate (19) (1.402 g, 5.5 mmol, 1 eq) in dry DMF (1 1 ml_), sodium hydride (60% dispersion in mineral oil, 262 mg, 6.6 mmol,
1.2 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1 hour. Then ((6-bromohexyloxy)methyl)benzene (97%, 1.6 ml_, 6.9 mmol, 1 .3 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for 4 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9.5:0.5 to n-Hex/EtOAc 9:1 ) to give 2.185 g of 20 (89%) as a colourless oil. Rf = 0.14 (n-Hex/EtOAc 9.5:0.5). 1H NMR (400 MHz, CDCI3) δ 7.38 - 7.26 (m, 5H), 4.49 (s, 2H), 4.15 (q, J = 7.1 Hz, 4H), 3.45 (t, J = 6.6 Hz, 2H), 1 .93 - 1 .85 (m, 2H), 1.83 (d, J = 5.9 Hz, 2H), 1 .68 - 1 .52 (m, 8H), 1 .41 - 1.28 (m, 4H), 1.27 - 1.19 (m, 1 H), 1 .23 (t, J = 7.1 Hz, 6H), 1.19 - 1.07 (m, 4H), 0.99 - 0.86 (m, 2H); 13C NMR (100 MHz, CDCI3) δ 172.5, 138.8, 128.5, 127.7, 127.6, 73.0, 70.5, 61.1 , 56.9, 39.4, 34.4, 33.6, 32.7, 29.9, 29.8, 26.4, 26.3, 26.1 , 24.2, 14.2; ESI MS m/z: calcd. for C27H4305 [/W+H]+ 447.3, C27H42Na05
[/W+Na]+ 469.3, found: 447.3, 469.3. Svnthesis 21
5-(6-(Benzyloxy)hexyl)-5-(cyclohexylmethyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (21 )
Figure imgf000091_0001
To a suspension of urea (99%, 2.691 g, 44.3 mmol, 10 eq) in dry DMF (13 mL), sodium hydride (60% dispersion in mineral oil, 706 mg, 17.6 mmol, 4 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1 hour. Then a solution of 20 (1 .971 g, 4.4 mmol, 1 eq) in dry DMF (3 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for one night. The reaction was quenched with a saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7.5:2.5) to give 1 .603 g of 21 (88%) as a white solid. Rf = 0.34 (n-Hex/EtOAc 7.5:2.5). 1H NMR (400 MHz, CDCI3) δ 8.26 (s, 2H), 7.38 - 7.26 (m, 5H), 4.48 (s, 2H), 3.42 (t, J = 6.5 Hz, 2H), 1.97 (d, J = 6.7 Hz, 2H), 1.95 - 1.87 (m, 2H), 1 .67 - 1 .47 (m, 7H), 1.38 - 1.00 (m, 10H), 0.98 - 0.83 (m, 2H). 13C NMR (100 MHz, CDCI3) 5 173.1 , 149.5, 138.6, 128.5, 127.8, 127.6, 72.9, 70.2, 55.2, 45.8, 41 .7, 35.0, 33.8, 29.6, 29.3, 26.1 , 26.0, 25.8, 24.6; ESI MS m/z: calcd. for C24H35N204 [/W+H]+ 415.3, C24H34N2Na04 [/W+Na]+ 437.2, found: 415.3, 437.3.
Synthesis 22
5-(Cyclohexylmethyl)-5-(6-hydroxyhexyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (22)
Figure imgf000091_0002
A mixture of 21 (1 .342 g, 3.2 mmol) and 20% wt of 20% Pd(OH)2/C (168 mg) in MeOH (30 ml.) was stirred at room temperature under H2 atmosphere. After 40 hours, the mixture was filtered through Celite and the bed was washed with MeOH and then with EtOAc. The solvent was removed in vacuo and the residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 2:3) to afford 991 mg of 22 as a white solid (95%).
Rf = 0.40 (n-Hex/EtOAc 2:3). 1 H NMR (400 MHz, CD3OD) δ 3.51 (t, J = 6.6 Hz, 2H), 1.95 - 1 .81 (m, 4H), 1 .72 - 1 .52 (m, 5H), 1.52 - 1.43 (m, 2H), 1.38 - 1 .06 (m, 10H), 0.99 - 0.85 (m, 2H); 13C NMR (100 MHz, CD3OD) δ 175.3, 151 .3, 62.8, 55.7, 47.1 , 42.2, 36.4, 35.0, 33.4, 30.3, 27.2, 27.1 , 26.4, 25.6; ESI MS m/z: calcd. for Ci7H29N204 [/W+H]+ 325.2, Ci7H28N2Na04 [/W+Na]+ 347.2, found: 325.2, 347.2.
Synthesis 23
5-(Cyclohexylmethyl)-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (23)
Figure imgf000092_0001
To a solution of 22 (205 mg, 0.63 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (5 ml.) diethylaminosulfur trifluoride (DAST) (>90%, 190 μΙ_, 1.3 mmol, 2.1 eq) was added at -78°C. The reaction mixture was stirred at this temperature for 15 minutes under nitrogen atmosphere and then it was allowed to warm to room temperature. The reaction was stirred at room temperature for 4 hours, cooled again to -78°C and a second portion of DAST (>90%, 190 μΙ_, 1.3 mmol, 2.1 eq) was added. Reaction mixture was stirred at this temperature for 10 minutes and then it was warmed to room temperature and stirred for 2.5 hours. Water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 7.5:2.5) to afford 150 mg of 23 as a white solid (73%).
Rf = 0.32 (n-Hex/EtOAc 7.5:2.5). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 21 .2 minutes; the purity was > 99% λ = 214 nm. 1H NMR (400 MHz, CD3OD) δ 4.38 (dt, J = 47.5, 6.1 Hz, 2H), 1.99- 1.79 (m, 4H), 1.75- 1.48 (m, 7H), 1.46- 1.03 (m, 10H), 1.01 -0.83 (m, 2H); 13C NMR(100 MHz, CD3OD) δ 175.3, 151.3, 84.7 (d, J= 163.8 Hz), 55.7, 47.1, 42.1, 36.4, 35.0, 31.3 (d, J= 19.6 Hz), 30.1, 27.2, 27.1, 25.8 (d, J= 5.4 Hz), 25.5; 19F NMR (376 MHz, CD3OD) δ -219.78 - -220.26 (m); ESI MS m/z: calcd. for C17H28FN2O3 [/W+H]+ 327.2, C17H27FN2Na03 [M+Ua] + 349.2, found: 327.2, 349.2.
Synthesis 24
6-(5-(Cyclohexylmethyl)-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4- methylbenzenesulfonate (24)
Figure imgf000093_0001
Using a method analogous to Method A, with 5-(cyclohexylmethyl)-5-(6-hydroxyhexyl) pyrimidine-2,4,6(1 H,3H,5H)-tr\one (22), the title compound was obtained as a white solid (77%). Rf = 0.24 (n-Hex/EtOAc 7:3). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1%TFA, solvent B: CH3CN+0.1%TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 23.4 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CDCI3) δ 8.84 (s, 2H), 7.77 (d, J = 8.3 Hz, 2H), 7.34 (d, J = 8.0 Hz, 2H), 3.97 (t, J = 6.4 Hz, 2H), 2.44 (s, 3H), 1.96 (d, J =6.5 Hz, 2H), 1.93- 1.82 (m, 2H), 1.69- 1.44 (m, 7H), 1.32- 1.02 (m, 10H), 0.98- 0.82 (m, 2H); 13C NMR (100 MHz, CDCI3) δ 172.9, 149.2, 144.8, 133.2, 130.0, 128.0, 70.4, 55.1, 45.9, 41.4, 35.0, 33.8, 28.8, 28.7, 26.1, 26.0, 25.0, 24.4, 21.7; ESI MS m/z: calcd. for C24H35N206S [M+H]+ 479.2, C24H34N2Na06S [M+Ua]+ 501.2, found: 479.2, 501.2. Synthesis 25
5-(Cyclohexylmethyl)-5-(6-[18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (25)
Figure imgf000094_0001
Using a method analogous to Method B, with 6-(5-(cyclohexylmethyl)-2,4,6- trioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (24) the title compound was obtained.
The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-(cyclohexylmethyl)-5-(6-fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr\one (23) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x I D), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B:
CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time in the UV-chromatogram was identical to the retention time of 5-(cyclohexylmethyl)-5-(6- [18F]fluorohexyl)pyrimidine-2,4,6(1 H,3H,5H)-tr\one (25) in the radioactivity chromatogram.
Synthesis 26
5-(Bromomethyl)-2-chloropyridine (26).
Figure imgf000094_0002
To a solution of (6-chloropyridin-3-yl)methanol (1 .005 g, 7.0 mmol, 1 eq) in dry DCM
(20 ml.) CBr4 (99%, 2.885 g, 8.6 mmol, 1 .2 eq) was added. This solution was cooled to 0°C and then Ph3P (2.297 g, 8.7 mmol, 1 .2 eq) was added. The reaction mixture was stirred at 0°C for 15 minutes under nitrogen atmosphere and then it was allowed to warm to room temperature. After 4.5 hours the reaction mixture was treated with 20 ml. of water and extracted with DCM. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9: 1 ) to afford 1 .231 g of 26 as white solid (85%).
0.33 (n-Hex/EtOAc 9:1 ). 1 H NMR (400 MHz, CDCI3) δ 8.40 (d, J = 2.5 Hz, 1 H), 7.70 J = 8.2, 2.6 Hz, 1 H), 7.33 (d, J = 8.3 Hz, 1 H), 4.44 (s, 2H); 13C NMR (100 MHz, CDCI3) 5 151.4, 149.6, 139.5, 132.8, 124.6, 28.5; ESI MS m/z: calcd. for C6H6BrCIN [/W+H]+ 205.9, found: 205.9, 207.9, 209.9.
Synthesis 27
Diethyl 2-((6-chloropyridin-3-yl)methyl)-2-ethylmalonate (27)
Figure imgf000095_0001
To a solution of diethyl 2-ethylmalonate (99%, 880 μΙ_, 4.6 mmol, 1.2 eq) in dry DMF (10 ml_), sodium hydride (60% dispersion in mineral oil, 222 mg, 5.5 mmol, 1 .4 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1 hour. Then 26 (800 mg, 3.9 mmol, 1 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for 4.5 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash
chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 8.5:1 .5) to give 1.087 g of 27 (89%) as a pale yellow oil.
Rf = 0.25 (n-Hex/EtOAc 9:1 ). 1 H NMR (400 MHz, CDCI3) δ 8.1 1 (d, J = 2.1 Hz, 1 H), 7.40 (dd, J = 8.2, 2.5 Hz, 1 H), 7.19 (d, J = 8.2 Hz, 1 H), 4.22 - 4.06 (m, 4H), 3.15 (s, 2H), 1 .82 (q, J = 7.5 Hz, 2H), 1.19 (t, J = 7.1 Hz, 6H), 0.89 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCI3) 5 170.9, 151 .1 , 150.4, 140.4, 131 .4, 124.0, 61.7, 59.4, 34.6, 25.8, 14.3, 8.8; ESI MS m/z: calcd. for Ci5H2iCIN04 [/W+H]+ 314.1 , Ci5H20CINNaO4 [/W+Na]+ 336.1 , found: 314.1 , 316.1 , 336.1 , 338.1 .
Synthesis 28
Diethyl 2-ethyl-2-((6-fluoropyridin-3-yl)methyl)malonate (28)
Figure imgf000095_0002
To a solution of diethyl 2-ethylmalonate (99%, 300 μΙ_, 1.6 mmol, 1.2 eq) in dry DMF (3 ml_), sodium hydride (60% dispersion in mineral oil, 77 mg, 1.9 mmol, 1 .5 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 2 hours. Then a solution of 5-(bromomethyl)-2-fluoropyridine (250 mg, 1 .3 mmol, 1 eq) in dry DMF (2 ml.) was added. The solution was stirred at room temperature under nitrogen atmosphere for 4 hours. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 8.5:1 .5) to give 172 mg of 28 (44%) as a pale yellow oil. Rf = 0.22 (n-Hex/EtOAc 9:1 ). 1 H NMR (400 MHz, CDCI3) δ 7.97 (d, J = 2.2 Hz, 1 H), 7.60 - 7.52 (m, 1 H), 6.83 (dd, J = 8.4, 2.9 Hz, 1 H), 4.24 - 4.10 (m, 4H), 3.20 (s, 2H), 1.86 (q, J = 7.6 Hz, 2H), 1.23 (t, J = 7.1 Hz, 6H), 0.93 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCI3) 5 170.9, 163.0 (d, J = 238.6 Hz), 148.7 (d, J = 14.5 Hz), 142.6 (d, J = 7.8 Hz), 129.9 (d, J = 4.7 Hz), 109.1 (d, J = 37.3 Hz), 61.5, 59.3, 34.3, 25.6, 14.2, 8.7; 19F NMR (376 MHz, CDCI3) δ -70.61 (d, J = 6.6 Hz); ESI MS m/z: calcd. for Ci5H2iFN04 [/W+H]+ 298.1 , Ci5H20FNNaO4 [/W+Na]+ 320.1 , Ci5H20FKNO4 [/W+K]+ 336.1 , found: 298.1 , 320.1 , 336.1 .
Synthesis 29
5-((6-Chloropyridin-3-yl)methyl)-5-ethylpyrimidine-2, 4,6(1 H,3H,5H)-trione (29)
Figure imgf000096_0001
To a suspension of urea (99%, 308 mg, 5.1 mmol, 10 eq) in dry DMF (7 ml_), sodium hydride (60% dispersion in mineral oil, 82 mg, 2.1 mmol, 4 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1.5 hours. Then a solution of 27 (160 mg, 0.51 mmol, 1 eq) in dry DMF (3 ml.) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 2 hours. The reaction was quenched with a cold saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 3:2) to give 82 mg of 29
(57%) as a white solid. Rf = 0.56 (n-Hex/EtOAc 1 :1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 12.9 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CD3OD) δ 8.10 (d, J = 2.4 Hz, 1 H), 7.56 (dd, J = 8.3, 2.5 Hz, 1 H), 7.37 (d, J = 8.2 Hz, 1 H), 3.23 (s, 2H), 2.12 (q, J = 7.5 Hz, 2H), 0.91 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CD3OD) δ 173.8, 151.5, 150.7, 141.9, 132.3, 125.4, 59.5, 40.5, 33.6, 9.5; ES/ MS m/z: calcd. for Ci2H13CIN303 [M+H]+ 282.1 , Ci2H12CIN3Na03 [M+Ua]+ 304.0, found: 282.0, 284.0, 304.0, 306.0.
Synthesis 30
5-Ethyl-5-((6-fluoropyridin-3-yl)methyl)pyrimidine-2,4,6(1 H,3H,5H)-trione (30)
Figure imgf000097_0001
To a suspension of urea (99%, 153 mg, 2.5 mmol, 10 eq) in dry DMF (3 mL), sodium hydride (60% dispersion in mineral oil, 43 mg, 1.1 mmol, 4 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1 hour. Then a solution of 28 (75 mg, 0.25 mmol, 1 eq) in dry DMF (2 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 2 hours. The reaction was quenched with a cold saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 1 :1 ) to give 33 mg of 30 (50%) as a white solid. Rf = 0.55 (n-Hex/EtOAc 1 :1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 1 1.9 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CD3OD) δ 7.93 (d, J = 2.4 Hz, 1 H), 7.68 (td, J = 8.2, 2.5 Hz, 1 H), 6.98 (dd, J = 8.5, 2.4 Hz, 1 H), 3.24 (s, 2H), 2.12 (q, J = 7.5 Hz, 2H), 0.91 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CD3OD) δ 173.9, 164.4 (d, J = 239.2 Hz), 150.7, 149.3 (d, J = 14.0 Hz), 144.3 (d, J = 8.2 Hz), 130.9 (d, J = 4.6 Hz), 1 10.5 (d, J = 37.0 Hz), 59.7, 40.5, 33.5, 9.6; 19F NMR (376 MHz, CD3OD) δ -72.68 (dd, J = 7.5, 1.7 Hz); ESI MS m/z: calcd. for C12H13FN303 [/W+H]+ 266.1 , C12H12FN3Na03
[/W+Na]+ 288.1 , found: 266.1 , 288.0.
Synthesis 31
5-Ethyl-5-((6-[18F]fluoropyridin-3-yl)methyl)pyrimidine-2,4,6(1 H,3H,5H-trione (31 )
Figure imgf000098_0001
Using a method analogous to Method B, with 5-((6-chloropyridin-3-yl)methyl)-5- ethylpyrimidine-2,4,6(1 H,3H,5H)-tr\one (29) the title compound was obtained. The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-ethyl-5-((6-fluoropyridin-3-yl)methyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (30) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B:
CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time in the UV-chromatogram was identical to the retention time of 5-ethyl-5-((6- [18F]fluoropyridin-3-yl)methyl)pyrimidine-2, 4,6(1 /-/,3/-/,5/-/)-trione (31 ) in the radioactivity chromatogram.
Synthesis 32
5-Ethyl-5-(6-fluorohexyl)-1 ,3-dimethylpyrimidine-2,4,6(1 H,3H,5H)-trione (32)
Figure imgf000098_0002
To a suspension of 5-ethyl-5-(6-fluorohexyl)pyrimidine-2, 4,6(1 /-/,3/-/,5/-/)-trione (4) (30 mg, 0.1 16 mmol, 1 eq) and K2C03 (87 mg, 0.63 mmol, 5.4 eq) in dry DMF (0.5 ml.) methyl iodide (99%, 1 1 μΙ_, 0.17 mmol, 1.5 eq) was added. The reaction mixture was stirred at room temperature under nitrogen atmosphere for 3 hours. Then the reaction mixture was acidified with 1 N HCI, diluted with water and extracted with small portions of diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 9:1 ) to afford 23 mg of 32 as a colourless oil (69%).
Rf = 0.30 (n-Hex/EtOAc 9:1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μΙ_, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 21.6 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CDCI3) δ 4.39 (dt, J = 47.3, 6.1 Hz, 2H), 3.32 (s, 6H), 2.08 - 1 .91 (m, 4H), 1 .69 - 1.54 (m, 2H), 1.37 - 1.22 (m, 4H), 1.12 - 0.99 (m, 2H), 0.75 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCI3) δ 172.1 , 151 .4, 84.1 (d, J = 164.4 Hz), 57.7, 39.5, 33.7, 30.3 (d, J = 19.5 Hz), 29.2, 28.6, 25.3, 24.9 (d, J = 5.3 Hz), 9.6; 19F NMR (564 MHz, CDCI3) δ -218.15 - -218.50 (m); ESI MS m/z: calcd. for Ci4H24FN203 [M+H]+ 287.2, Ci4H23FN2Na03 [M+Ua] + 309.2, found: 287.1 , 309.1.
Synthesis 33
6-(5-Ethyl-1 ,3-dimethyl-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4- methylbenzenesulfonate (33)
Figure imgf000099_0001
To a suspension of 6-(5-ethyl-2,4,6-trioxohexahydropyrimidin-5-yl)hexyl 4- methylbenzenesulfonate (5) (69 mg, 0.17 mmol, 1 eq) and K2C03 (126 mg, 0.91 mmol,
5.4 eq) in dry DMF (0.7 ml.) methyl iodide (99%, 22 μΙ_, 0.35 mmol, 2.1 eq) was added. The reaction mixture was stirred at room temperature under nitrogen atmosphere for
2.5 hours. Then the reaction mixture was acidified with 1 N HCI, diluted with water and extracted with small portions of diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 4:1 ) to afford 33 mg of 33 as white solid (44%).
Rf = 0.22 (n-Hex/EtOAc 4:1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 23.8 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1H NMR (400 MHz, CDCI3) δ 7.76 (d, J = 8.4 Hz, 2H), 7.34 (d, J = 7.9 Hz, 2H), 3.96 (t, J = 6.4 Hz, 2H), 3.32 (s, 6H), 2.44 (s, 3H), 1.98 (q, J = 7.4 Hz, 2H), 1.94 - 1.88 (m, 2H), 1.61 - 1 .52 (m, 2H), 1.28 - 1.1 1 (m, 4H), 1.04 - 0.95 (m, 2H), 0.74 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCI3) δ 172.0, 151 .3, 144.8, 133.2, 129.9, 128.0, 70.4, 57.6, 39.3, 33.8, 28.9, 28.8, 28.6, 25.2, 25.1 , 21 .8, 9.6; ESI MS m/z: calcd. for C2i H3iN206S [/W+H]+ 439.2, C2i H30N2NaO6S [/W+Na]+ 461.2, found: 439.2, 461.2.
Synthesis 34
5-Ethyl-5-(6-[18F]fluorohexyl)-1 ,3-dimethylpyrimidine-2,4,6(1 H,3H,5H)-trione (34)
Figure imgf000100_0001
Using a method analogous to Method B, with 6-(5-ethyl-1 ,3-dimethyl-2,4,6- trioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (33) the title compound was obtained.
The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-ethyl-5-(6-fluorohexyl)-1 , 3-dimethylpyrimidine-2, 4,6(1 /-/,3/-/,5/-/)-trione (32) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηι, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B:
CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time in the UV-chromatogram was identical to the retention time of 5-ethyl-5-(6- [18F]fluorohexyl)-1 ,3-dimethylpyrimidine-2,4,6(1 H,3H,5H)-trione (34) in the radioactivity chromatogram. Synthesis 35
Diethyl 2-(6-(te/t-butyldimethylsilyloxy)hexyl)-2-ethylmalonate (35)
Figure imgf000101_0001
To a solution of diethyl 2-ethylmalonate (99%, 1 .9 mL, 10.0 mmol, 1 eq) in dry DMF (20 mL), sodium hydride (60% dispersion in mineral oil, 515 mg, 12.9 mmol, 1 .2 eq) was added at 0°C. The suspension was stirred under nitrogen atmosphere at 0°C for 1 hour. Then (6-bromohexyloxy)(te/?-butyl)dimethylsilane (99%, 3.4 mL, 12.0 mmol, 1 .3 eq) was added. The solution was stirred at room temperature under nitrogen atmosphere for one night. The reaction mixture was quenched with a saturated aqueous NH4CI solution and extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9.5:0.5 to n-Hex/EtOAc 9:1 ) to give 3.024 g of 35 (75%) as a pale yellow oil. Rf = 0.29 (n-Hex/EtOAc 9.5:0.5). 1H NMR (400 MHz, CDCI3) 5 4.16 (q, J = 7.1 Hz, 4H), 3.57 (t, J = 6.6 Hz, 2H), 1.91 (q, J = 7.6 Hz, 2H), 1 .87 - 1 .81 (m, 2H), 1 .52 - 1.44 (m, 2H), 1.34 - 1 .27 (m, 4H), 1.23 (t, J = 7.1 Hz, 6H), 1.19 - 1 .09 (m, 2H), 0.88 (s, 9H), 0.80 (t, J = 7.6 Hz, 3H), 0.03 (s, 6H); 13C NMR (100 MHz, CDCI3) δ 172.0, 63.3, 61.0, 58.0, 32.9, 31 .6, 29.8, 26.1 , 25.7, 25.3, 24.0, 18.5, 14.2, 8.5, -5.2; ES/ MS m/z: calcd. for C2iH4305Si [/W+H]+ 403.3, C2iH42Na05Si [/W+Na]+ 425.3, found: 403.3, 425.3.
Synthesis 36
5-(6-(7eri-butyldimethylsilyloxy)hexyl)-5-ethyl-2-thioxodihydropyrimidine-4,6(1 H,5H)-d\one
Figure imgf000101_0002
To a suspension of thiourea (99%, 2.552 g, 33.2 mmol, 10 eq) in dry DMF (12 mL), sodium hydride (60% dispersion in mineral oil, 676 mg, 16.9 mmol, 5.1 eq) was added at 0°C. The mixture was stirred under nitrogen atmosphere at 0°C for 1 hour. Then a solution of diethyl 2-(6-(iert-butyldimethylsilyloxy)hexyl)-2-ethylmalonate (35) (1 .330 g, 3.3 mmol, 1 eq) in dry DMF (2 mL) was added. The reaction mixture was stirred under nitrogen atmosphere at room temperature for 2 days. The reaction was quenched with a saturated aqueous NH4CI solution. The aqueous layer was extracted with small portions of diethyl ether. The collected organic phases were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (n-Hex/EtOAc 4:1 ) to give 1 .032 g of 36 (81 %) as a white solid.
Rf = 0.25 (n-Hex/EtOAc 9:1 ). 1H NMR (400 MHz, CDCI3) δ 9.01 (s, 2H), 3.56 (t, J = 6.5 Hz, 2H), 2.05 (q, J = 7.4 Hz, 2H), 2.01 - 1 .95 (m, 2H), 1.51 - 1.39 (m, 2H), 1 .33 - 1 .15 (m, 6H), 0.88 (s, 12H), 0.03 (s, 6H); 13C NMR (100 MHz, CDCI3) δ 176.2, 170.8, 63.2, 57.7, 38.8, 32.8, 32.7, 29.4, 26.1 , 25.5, 25.3, 18.5, 9.6, -5.1 ; ES/ MS m/z: calcd. for Ci8H35N203SSi [/W+H]+ 387.2, found: 387.2.
Synthesis 37
5-Ethyl-5-(6-hydroxyhexyl)-2-thioxodihydropyrimidine-4,6(1 /-/,5/-/)-dione (37)
Figure imgf000102_0001
To a solution of 5-(6-(ieri-butyldimethylsilyloxy)hexyl)-5-ethyl-2-thioxodihydropyrimidine- 4,6(1 H,5H)-dione (36) (297 mg, 0.77 mmol, 1 eq) in dry THF (1.3 mL) tetra-n- butylammonium fluoride (TBAF) (1 M THF solution, 1 .2 mL, 1.2 mmol, 1.5 eq) was added at 0°C. The reaction mixture was stirred at this temperature for 1 hour under nitrogen atmosphere and then it was allowed to warm to room temperature. After 3.5 hours another portion of TBAF (1 M THF solution, 1.2 mL, 1 .2 mmol, 1 .5 eq) was added and the reaction mixture was stirred at room temperature for another 20 hours. Then 1 N HCI was added and the mixture was extracted with EtOAc. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 1 :1 to n-Hex/EtOAc 3:7) to afford 187 mg of 37 as a pale yellow solid (89%). Rf = 0.39 (n- Hex/EtOAc 1 :1 ). 1 H NMR (400 MHz, CD3OD) δ 3.52 (t, J = 6.6 Hz, 2H), 2.03 - 1 .87 (m, 4H), 1 .56 - 1 .42 (m, 2H), 1.35 - 1.16 (m, 6H), 0.85 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CD3OD) δ 179.8, 172.9, 62.8, 58.2, 39.7, 33.6, 33.4, 30.4, 26.4, 26.1 , 9.5; ESI MS m/z: calcd. for C12H21N2O3S [/W+H]+ 273.1 , found: 273.1.
Synthesis 38
5-Ethyl-5-(6-fluorohexyl)-2-thioxodihydropyrimidine-4,6(1 /-/,5/-/)-dione (38)
Figure imgf000103_0001
To a solution of 5-ethyl-5-(6-hydroxyhexyl)-2-thioxodihydropyrimidine-4,6(1 /-/,5/-/)-dione (37) (121 mg, 0.44 mmol, 1 eq) in dry 1 ,2-dimethoxyethane (DME) (4 ml.)
diethylaminosulfur trifluoride (DAST) (>90%, 130 μΙ_, 0.89 mmol, 2 eq) was added at -78°C. The reaction mixture was stirred at this temperature for 15 minutes under nitrogen atmosphere and then it was allowed to warm to room temperature. After 4 hours water was added and the mixture was extracted with diethyl ether. The combined organic extracts were dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel (gradient: from n-Hex/EtOAc 9:1 to n-Hex/EtOAc 4:1 ) to afford 20 mg of 38 as a white solid (16%).
Rf = 0.40 (n-Hex/EtOAc 4:1 ). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x ID), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 18.3 minutes; the purity was > 99% λ = 214 nm. 1H NMR (400 MHz, CDCI3) δ 9.34 (s, 2H), 4.40 (dt, J = 47.3, 6.1 Hz, 2H), 2.18 - 1.90 (m, 4H), 1 .73 - 1 .57 (m, 2H), 1 .38 - 1 .18 (m, 6H), 0.90 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCI3) δ 176.1 , 170.6, 84.1 (d, J = 164.4 Hz), 57.7, 38.5, 32.9, 30.3 (d, J = 19.6 Hz), 29.1 , 25.2, 24.9 (d, J = 5.3 Hz), 9.6; 19F NMR (376 MHz, CDCI3) δ - 217.94 - -218.59 (m); ES/ MS m/z: calcd. for C12H20FN2O2S [/W+H]+ 275.1 ,
Ci2H19FN2Na02S [/W+Na] + 297.1 , found: 275.1 , 297.1. Svnthesis 39
6-(5-Ethyl-4,6-dioxo-2-thioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate
Figure imgf000104_0001
Using a method analogous to Method A, with 5-ethyl-5-(6-hydroxyhexyl)-2- thioxodihydropyrimidine-4,6(1 H,5H)-d\one (37), the title compound was obtained as a white solid (62%).
Rf = 0.35 (n-Hex/EtOAc 7:3). The product was analysed by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x I D), volume injected 20 μί, flow rate 1 mL/min, solvent A: H2O+0.1 %TFA, solvent B: CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time was 21 .1 minutes; the purity was > 99% λ = 214 nm, 254 nm, 220 nm. 1 H NMR (400 MHz, CDCI3) δ 9.28 (s, 2H), 7.78 (d, J = 8.2 Hz, 2H), 7.34 (d, J = 8.1 Hz, 2H), 3.98 (t, J = 6.4 Hz, 2H), 2.45 (s, 3H), 2.03 (q, J = 7.4 Hz, 2H), 1 .99 - 1 .88 (m, 2H), 1 .64 - 1 .53 (m, 2H), 1 .32 - 1 .10 (m, 6H), 0.89 (t, J = 7.4 Hz, 3H); 13C NMR (100 MHz, CDCI3) δ 176.0, 170.5, 144.8, 133.2, 130.0, 128.0, 70.4, 57.6, 38.4, 32.9, 28.8, 28.7, 25.0, 21 .8, 9.5; ESI MS m/z: calcd. for Ci9H27N205S2 [M+H]+ 427.1 , Ci9H26N2Na05S2 [/W+Na]+ 449.1 , found: 427.2, 449.1 .
Synthesis 40
5-Ethyl-5-(6-[18F]fluorohexyl)-2-thioxodihydropyrimidine-4,6(1 H,5H)-dione (40)
Figure imgf000104_0002
Using a method analogous to Method B, with 6-(5-ethyl-4,6-dioxo-2- thioxohexahydropyrimidin-5-yl)hexyl 4-methylbenzenesulfonate (39) the title compound was obtained. The identity of the 18F labelled product was confirmed by co-injection with the 19F cold standard 5-ethyl-5-(6-fluorohexyl)-2-thioxodihydropyrimidine-4,6(1 H,5H)-d\one (38) on the same column. The product was solubilised in CH3CN and analised by analytical HPLC as follows: Phenomenex Luna C18, 5 μηη, 100 A, 250 mm x 4.6 mm (L x I D), volume injected 20 μί, flow rate 1 mL/min, solvent A: H20, solvent A: H2O+0.1 %TFA, solvent B:
CH3CN+0.1 %TFA, 15%B for 3 min, linear gradient to 90%B in 20 min. The retention time in the UV-chromatogram was identical to the retention time of 5-ethyl-5-(6- [18F]fluorohexyl)-2-thioxodihydropyrimidine-4,6(1 H,5H)-d\one (40) in the radioactivity chromatogram.
Biological Methods
Thioflavin T (ThT) Displacement Assay Thioflavin T is a dye commonly used to quantify the presence of amyloid fibrils. ThT has no intrinsic fluorescence, and thus shows only minimal emission in the absence of binding, but specifically binds to β amyloid fibrils giving strong fluorescence and a ten-fold increase in emission. Binding results in a fluorescent signal with emission at 485 nm, upon excitation at 440 nM, the intensity of which is directly proportional to the mass of the formed fibril. The affinity of a test compound for β amyloid can be measured by determining its ability to displace bound ThT and observing the resultant decrease in fluorescence. The more strongly a compound binds to β amyloid, the greater the reduction in fluorescence seen. PET Imaging
Positron Emission Tomography (PET) is a powerful non-invasive molecular imaging technique. It is used to study and visualise in vivo biological disorders at the molecular level before anatomical changes become apparent, by detection of positron-emitting radiotracers. Therefore, PET may be used for early detection and monitoring of diseases, as well as investigating the efficacy of drugs. The information that PET provides at molecular level about biochemical processes (functional information) is not available from other conventional imaging techniques such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). On the other hand, these imaging modalities provide a detailed picture of the body's internal anatomy (anatomical information). The combination of PET with one of both of these imaging tools allows the matching of functional and anatomical information. For example, the combined PET/CT technique provides complete information both on disease location and metabolism. This means that small lesions such as tangles and Αβ plaques, which may not show anatomical changes in size or shape, could be detected with PET (high sensitivity) and then exactly located with CT (high resolution).
A suitable tracer labelled with a positron-emitting isotope is administered to the subject, typically parenterally (e.g., by intravenous injection, intravenous infusion, etc.). The tracer accumulates in the region of the body under study. It decays by positron emission. The emitted positron (γ+) travels a short distance in the surrounding tissue before it is annihilated by interaction with an electron. The distance travelled by the positron before annihilation is called the "positron range". The path length is determined by the energy of the emitted positron, which is different for each positron-emitting radionuclide. The larger the positron energy, the larger the distance the proton travels before annihilation and the larger the loss in spatial resolution. The annihilation of positron with electron produces two gamma ray photons (γ) that travel in opposite directions (i.e., each at an angle of 180° with respect to the other). The detection of these two gamma ray photons by the detector ring of the PET scanner allows the localisation of the radiotracer in the body. Finally, a computer is used to create a series of images that use different colours or degrees of brightness to show the different distribution of the labelled probe within the body as a function of time.
APP/PSEN1 transgenic mice were used as a well-characterised model for AD. These animals develop a severe amyloid plaque load by the age of 9 months. Briefly, mice (transgenic mice or wild-type controls) were fasted overnight, injected intraperitoneally or intravenously with 18F-labelled test compound (range: 9.84-17.32 MBq in 0.33 - 0.5 ml.) while conscious. Uptake occurred in the dark over 45 minutes with free access to drinking water. Mice were kept warm by placing the cage on a heating pad (35°C) and warming started at least 30 minutes before 18F-labelled test compound administration and continued during the 18F-labelled test compound uptake period. For PET/CT imaging, animals were anesthetised with ketamine 100 mg/mL (Vetalar* V®) / medetomidine 1 mg/mL (Domitor®) / sterile water solution), and placed on the bed of the scanner in supine position (head first). The body and the head of the mouse were secured to the bed with tape.
CT and PET data were collected using a Suinsa ARGUS dual-ring PET/CT scanner, housed in a temperature-controlled room. Thirty-six position-sensitive PMT detector modules and a dual layer phoswich detector technology provide high quality pre-clinical images throughout the field of view. A CT scan was obtained first (with a voltage of 40 kV and a beam current of 140 μΑ) followed by a 40 minute list-mode PET acquisition (with a 250-700 keV energy window). The scanner had a ring diameter of 1 1.8 cm and a 4.8 cm axial field of view (FOV). 3-Dimensional (3D) sinograms were converted into
2-Dimensional (2D) sinograms before image reconstruction by Fourier rebinning. Images were then reconstructed by 2D-OSEM (two-dimensional ordered subsets expectation maximization) reconstruction algorithm using the manufacturer's software. Corrections for random coincidence counts, attenuation and photon scatter were applied.
All registration processing of the images to a standard template for voxel-based analysis was carried out using the Pmod suite of image processing tools (Pmod
Technologies, CH). Prior to analysis, the data were loaded into a database and the known shifts were applied to the PET data to bring it into alignment with the CT data. Data are registered to the CT image of the Digimouse atlas
(http://neuroimage.usc.edu/Digimouse.html). Co-registration involves non-linear warping of the data to match the template image using the Brain Norm II algorithm from Pmod version 3.0. As CT data have a higher resolution and higher noise levels than the atlas image and are in Hounsfield units rather than the relative scale used by the atlas, the images were smoothed using a 3D Gaussian filter with FWHM of 0.5 mm in all directions. The dynamic range of the CT images was also adjusted to match that of the atlas. Finally, if any truncation artefacts were visible, these were removed from the CT images. A 3D region of interest that fully encompassed the head of the mouse was drawn on the images by hand and all voxels outside this region were set to zero.
To accurately align CT images to the Digimouse atlas, manual alignment was initially achieved based on three orthogonal views through the CT images to determine rigid transformation parameters (i.e., shifts and rotations with respect to the three axes) that brought the images into rough alignment. Subsequently, the Brain Norm II algorithm was used to perform non-linear warping. This algorithm is designed for use with human brain images, but confirmed to work well with mouse pre-processed CT images, provided the size of the voxels was scaled by a factor of 10. Good fits and low residual errors were obtained in all cases.
For PET registration, the rigid and non-linear warping transformations calculated for the CT images (automatically aligned) were also applied to register images to the Digimouse template. As voxel values in PET images are influenced by a number of factors (e.g., injected dose, weight of the animal, pharmacokinetics of the FDG), normalisation of the images was required. Thus, data was normalized either via whole brain, or relative to a pre-selected brain region not affected by the disorder (e.g., cerebellum) as a reference region.
Once images were normalised to a standard atlas, the Statistical Parametric Mapping package (SPM, Functional Imaging Lab, London, UK) was used to determine differences between groups (two sample t-test). Uncorrected SPMs (separately for areas of increase and decrease) were produced to show clusters of voxels with a statistically significant (p < 0.05 and p < 0.01 levels) difference between groups. The images were filtered to display only clusters of >10 voxels in order to reduce false positives. Regions of statistically significant increase and decrease were overlaid on a CT image for display and 3D rendered objects were produced using Pmod. Biological Data
Biological Study 1 The affinity of a representative fluorinated barbiturate for amyloid-342 was determined using the Thioflavine T (ThT) binding assay, as described above. Briefly, ThT (100 μΜ) and amyloid-342 (4.5 μΜ) were shaken at room temperature for 5 seconds and the fluorescence emission measured at 485 nm with excitation at 440 nm. 5-Ethyl-5-(6- [18F]fluorohexyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)-trione (6) (22.5 μΜ final concentration) was added and the resultant reduction in fluorescence measured. The data are summarised in the following table.
Figure imgf000109_0001
It is evident from the data that (6) reduces the emission at 485 nm from 859 to 719 fluorescence units, thus demonstrating that the concentration of bound ThT is reduced, that (6) displaces THT from amyloid-342, and therefore that (6) has good affinity for amyloid-342. β-amyloid peptides are the main protein components of neuritic plaques, one of the most important pathological characteristics of Alzheimer's disease (AD). These data demonstrate that fluorinated barbiturates such as (6): have good affinity for β-amyloid; target structures specific to AD; and can be used for imaging the pathology associated with AD. Biological Study 2
The affinity of fluorinated barbiturates for amyloid plaque was also measured using PET imaging as described above. 5-Ethyl-5-(6-[18F]fluorohexyl)pyrimidine-2,4,6(1 /-/,3/-/,5/-/)- trione (6) was injected into wild-type or APP/PSEN1 mice (Jackson Laboratories) and the positron emission measured in various parts of the brain by PET imaging, as described above. The SUV (Standardized Uptake Value) after 13 minutes from intravenous injection of (6) into mice for different parts of the brain are shown in the following table. Table 2
Brain region Wild type APP/PSEN1 transgenic
Striatum 0.132 0.159
Cortex 0.126 0.155
Hippocampus 0.130 0.159
Thalamus 0.128 0.164
Cerebellum 0.133 0.168
Basal Forebrain & Septum 0.133 0.163
Hypothalamus 0.133 0.178
Amygdale 0.127 0.159
Brain Stem 0.141 0.175
Superior Colliculi 0.128 0.163
Olfactory Bulb 0.128 0.156
Mid Brain 0.133 0.169
Inferior Colliculi 0.132 0.167
The data demonstrate that there is increased positron emission (and thus accumulation of (6)) in most regions of the brain for the transgenic mouse in comparison with the wild type mouse.
The APP/PSEN transgenic mouse is a well-characterised Alzheimer's disease (AD) model and has a heavy amyloid plaque load. These data show an increased
accumulation of (6) in the presence of amyloid plaque, and demonstrate that
fluorobarbiturates such as (6) can be used to identify and image amyloid plaque and AD.
The foregoing has described the principles, preferred embodiments, and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Instead, the above-described embodiments should be regarded as illustrative rather than restrictive. It should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present invention. REFERENCES
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Claims

1. A compound of the following formula:
Figure imgf000114_0001
or a pharmaceutically acceptable salt or solvate thereof;
wherein:
=X is independently =0 or =S;
-A1 is independently -H, -A1A, or -A1B;
-A1A is saturated aliphatic Cr4alkyl;
-A1B is saturated C3-6cycloalkyl;
-A2 is independently -H, -A2A, or -A2B;
-A2A is saturated aliphatic Ci-4alkyl;
-A2B is saturated C3-6cycloalkyl;
-Ad is independently -A3A, -A3B, -L3-A3B -A3C, -L3-A3C, -A3D, -L3-A3D, -A3E, or
-L3-A;
-A3A is independently -A3A1, -A3A2, or -A3A3;
-A3A1 is saturated aliphatic C1-10alkyl, and is optionally substituted, for example, with one or more groups -Rx;
-A3A2 is aliphatic C2-ioalkenyl, and is optionally substituted, for example, with one or more groups -Rx;
-A3A3 is aliphatic C2-ioalkynyl, and is optionally substituted, for example, with one or more groups -Rx; each -A3B is independently -A3B1 or -A3B2;
each -A3B1 is saturated C3-7cycloalkyl, and is optionally substituted, for example, with one or more groups -RY;
each -A3B2 is C4-7cycloalkenyl, and is optionally substituted, for example, with one or more groups -RY; each -A phenyl, and is optionally substituted, for example, with one or more groups -RY; each -A3D is C5-6heteroaryl, and is optionally substituted, for example, with one or more groups -RY; each -A3E is non-aromatic C4-7heterocyclyl, and is optionally substituted, for example, with one or more groups -RY; each -L3- is saturated aliphatic Ci-4alkylene;
-A4 is independently -A4A, -A4B, -L4-A4B, -A4C, -L4-A4C, -A4D, or -L4-A4D; dependently -A4A1, -A4A2, or -A4A3-
-A is saturated aliphatic Ci-i0alkyl substituted with one or more groups -RFA, and optionally is further substituted, for example, with one or more groups -Rx;
-A4A2 is aliphatic C2-ioalkenyl substituted with one or more groups -RFA, and optionally is further substituted, for example, with one or more groups -Rx;
-A4A3 is aliphatic C2-ioalkynyl substituted with one or more groups -RFA, and optionally is further substituted, for example, with one or more groups -Rx; each -A4B is independently -A4B1 or -A4B2;
each -A4B1 is saturated C3-7cycloalkyl substituted with one or more groups -RFB, and optionally is further substituted, for example, with one or more groups -RY;
each -A4B2 is C4-7cycloalkenyl substituted with one or more groups -RFB, and optionally is further substituted, for example, with one or more groups -RY; each -A is phenyl substituted with one or more groups -R ,
optionally is further substituted, for example, with one or more groups Y. each -A is C5-6heteroaryl substituted with one or more groups -R , and optionally is further substituted, for example, with one or more groups -RY; each -L4- is saturated aliphatic Ci-4alkylene; each -RFA is -RF1;
each -RFB is independently -RF1 or -RF2;
each -RFC is independently -RF1 or -RF2;
each -RFD is independently -RF1 or -RF2; each -RF1 is an 18F atom; each -RF2 is a saturated aliphatic C1-6alkyl group substituted with one or more 18F atoms; each -R , if present, is independently selected from:
-F, -CI, -Br, -I, -CF3, phenyl, -OH, -ORs, -OCF3, -NH2, -NHRS, -NRS 2, pyrrolidine piperidino, morpholino, piperazino, N-(Ci-4alkyl)-piperazino,
-NHC(=0)Rs, -NRsC(=0)Rs, -C(=0)Rs, -C(=0)OH, -C(=0)ORs, -C(=0)NH2,
Figure imgf000116_0001
-C(=0)-pyrrolidino, -C(=0)-piperidino,
-C(=0)-morpholino, -C(=0)-piperazino, -C(=0)-{N-(Ci-4alkyl)-piperazino}-, -SRS, -S(=0)Rs, -S(=0)2Rs, -S(=0)2NH2, -S(=0)2NHRs, -S(=0)2NRs 2,
-S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino, -S(=0)2-piperazino, -S(=0)2-{N-(Ci.4alkyl)-piperazino}-, -NHS(=0)2Rs, and -NRsS(=0)2Rs;
wherein each -Rs is independently saturated aliphatic Ci-6alkyl, phenyl, or -CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups independently selected from: -F, -CI, -Br, -I, -Rss, -CF3, -OH, -ORss, -OCF3, -NH2, -NHRSS, and -NRSS 2, wherein each -Rss is saturated aliphatic d^alkyl; and each -RY, if present, is independently selected from:
-F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidino, piperidino, morpholino, piperazino, N-(Ci-4alkyl)-piperazino,
-NHC(=0)RT, -NRTC(=0)RT, -C(=0)RT, -C(=0)OH, -C(=0)ORT, -C(=0)NH2,
Figure imgf000116_0002
-C(=0)-pyrrolidino, -C(=0)-piperidino,
-C(=0)-morpholino, -C(=0)-piperazino, -C(=0)-{N-(C1-4alkyl)-piperazino}-, -SRT, -S(=0)RT, -S(=0)2RT, -S(=0)2NH2, -S(=0)2NHRT, -S(=0)2NRT 2,
-S(=0)2-pyrrolidino, -S(=0)2-piperidino, -S(=0)2-morpholino, -S(=0)2-piperazino, -S(=0)2-{N-(Ci.4alkyl)-piperazino}-, -NHS(=0)2RT, and -NRTS(=0)2RT;
wherein each -RT is independently saturated aliphatic C1-6alkyl, phenyl, or -CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups independently selected from: -F, -CI, -Br, -I, -RTT, -CF3, -OH, -ORTT, -OCF3, -NH2, -NHRTT, or -NRTT 2, wherein each -RTT is saturated aliphatic C1-4alkyl.
2. A compound according to claim 1 , wherein =X is =0.
3. A compound according to claim 1 , wherein =X is =S.
4. A compound according to any one of claims 1 to 3, wherein -A1 is -H or -A1A.
5. A compound according to any one of claims 1 to 3, wherein -A1 is -H.
6. A compound according to any one of claims 1 to 5, wherein -A2 is -H or -A2A.
7. A compound according to any one of claims 1 to 5, wherein -A2 is -H.
8. A compound according to any one of claims 1 to 7, wherein -A1A, if present, is -Me.
9. A compound according to any one of claims 1 to 8, wherein -A2A, if present, is
-Me.
10. A compound according to any one of claims 1 to 9, wherein -A3 is independently -A3A, -A3B, -L3-A3B, -A3C, or -L3-A3C.
1 1 . A compound according to any one of claims 1 to 9, wherein -A3 is -A3A.
12. A compound according to any one of claims 1 to 9, wherein -A3 is -A3B.
13. A compound according to any one of claims 1 to 9, wherein -A3 is -L3-A3B.
14. A compound according to any one of claims 1 to 9, wherein -A3 is -A3C.
15. A compound according to any one of claims 1 to 9, wherein -A3 is -L3-A3C.
16. A compound according to any one of claims 1 to 15, wherein -A3A, if present, is -A3A1. 17. A compound according to any one of claims 1 to 16, wherein -A3A1, if present, is saturated aliphatic C1-6alkyl, and is optionally substituted with one or more groups -Rx.
18. A compound according to any one of claims 1 to 16, wherein -A3A1, if present, is independently -Me, -Et, -nPr, -iPr, -nBu, -iBu, -sBu, -tBu, -(CH2)4CH3,
-CH(CH3)(CH2)2CH3, -(CH2)2CH(CH3)2, -(CH2)5CH3, -CH(CH3)(CH2)3CH3, or -(CH2)3CH(CH3)2.
19. A compound according to any one of claims 1 to 16, wherein -A3A1, if present, is -Et.
20. A compound according to any one of claims 1 to 19, wherein each -A3B, if present, is -A3B1.
21 . A compound according to any one of claims 1 to 20, wherein each -A3B1,
if present, is saturated C4-6cycloalkyl, and is optionally substituted with one or more groups -RY.
22. A compound according to any one of claims 1 to 20, wherein each -A3B1,
if present, is saturated cyclopentyl or cyclohexyl.
23. A compound according to any one of claims 1 to 22, wherein each -A3C, if present, is phenyl.
24. A compound according to any one of claims 1 to 23, wherein each -L3-, if present, is -CH2-. 25. A compound according to any one of claims 1 to 24, wherein -A4 is independently -A4A, -A4C, -L4-A4C, -A4D, or -L4-A4D.
26. A compound according to any one of claims 1 to 24, wherein -A4 is -A4A. 27. A compound according to any one of claims 1 to 24, wherein -A4 is -A4C.
28. A compound according to any one of claims 1 to 24, wherein -A4 is -L4-A4C.
29. A compound according to any one of claims 1 to 24, wherein -A4 is -A4D.
30. A compound according to any one of claims 1 to 24, wherein -A4 is -L4-A4D.
31 . A compound according to any one of claims 1 to 30, wherein -A4A, if present, is -A4A1. A compound according to any one of claims 1 to 30, wherein -A , if present, saturated aliphatic C4-8alkyl substituted with one or more groups -RFA, and optionally is further substituted with one or more groups -Rx.
A compound according to any one of claims 1 to 30, wherein -A , if present, saturated aliphatic C4-8alkyl substituted with one or more groups -RFA.
Figure imgf000119_0001
A compound according to to 30, wherein -A , if present,
Figure imgf000119_0002
A compound according to any one of claims 1 to 35, wherein each -A , if present, is phenyl substituted with one or more groups -RFC.
A compound according to any one of claims 1 to 35, wherein each -A4C, if present, is independently:
Figure imgf000119_0003
38. A compound according to any one of claims 1 to 37, wherein each -A , if present, is independently pyridyl, pyrimidinyl, pyrazinyl, or pyridazinyl, substituted with one or more groups -RFD.
39. A compound according to any one of claims 1 to 37, wherein each -A , if present, is independently pyridyl substituted with exactly one group -RFD.
40. A compound according to any one of claims 1 to 39, wherein each -L4-, if present, is -CH2-.
41 . A compound according to any one of claims 1 to 40, wherein each -RFC, if present, is -RF1. 42. A compound according to any one of claims 1 to 41 , wherein each -RFD, if present,
A compound according to any one of claims 1 to 42, wherein each -R , if present, is independently selected from:
-F, -CI, -Br, -I, -OH, and -ORs;
wherein each -Rs is independently saturated aliphatic Ci-6alkyl, phenyl, or -CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups independently selected from: -F, -CI, -Br, -I, -Rss, -CF3, -OH, -ORss, -OCF3, -NH2, -NHRSS, and -NRSS 2;
wherein each -Rss is saturated aliphatic C^alkyl.
44. A compound according to any one of claims 1 to 42, wherein each -R , if present, is independently selected from: -F, -CI, -Br, and -I.
45. A compound according to any one of claims 1 to 44, wherein each -RY, if present, is independently selected from:
-F, -CI, -Br, -I, -RT, -CF3, phenyl, -OH, -ORT, -OCF3, -NH2, -NHRT, -NRT 2, pyrrolidine piperidino, morpholino, piperazino, and N-(Ci-4alkyl)-piperazino;
wherein each -RT is independently saturated aliphatic C1-6alkyl, phenyl, or
-CH2-phenyl;
wherein each phenyl is optionally substituted with one or more groups independently selected from: -F, -CI, -Br, -I, -RTT, -CF3, -OH, -ORTT, -OCF3, -NH2, -NHRTT, or -NRTT 2;
wherein each -RTT is saturated aliphatic Ci-4alkyl.
46. A compound according to any one of claims 1 to 44, wherein each -RY, if present, is independently selected from: -F, -CI, -Br, and -I.
47. A compound according to any one of claims 1 to 46, wherein -A3 and -A4 are different, and the carbon atom to which -A3 and -A4 are attached is in the (R) configuration. 48. A compound according to any one of claims 1 to 46, wherein -A3 and -A4 are different, and the carbon atom to which -A3 and -A4 are attached is in the (S) configuration.
49. A compound according to claim 1 , selected from compounds of the following formulae and pharmaceutically acceptable salts, hydrates, and solvates thereof:
Figure imgf000121_0001
Figure imgf000122_0001
A composition comprising a compound according to any one of claims 1 to 49, and a pharmaceutically acceptable carrier, diluent, or excipient.
A method of preparing a composition comprising admixing a compound according to any one of claims 1 to 49 and a pharmaceutically acceptable carrier, diluent, or excipient.
A compound according to any one of claims 1 to 49, for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of a human or animal subject.
Use of a compound according to any one of claims 1 to 49 in the manufacture of a medicament for use as an imaging agent in a method of positron emission imaging (e.g., positron emission tomography (PET) imaging of a human or animal subject.
A method of positron emission imaging (e.g., positron emission tomography (PET) imaging) of a human or animal subject which employs a compound according to any one of claims 1 to 49 as an imaging agent.
A method according to claim 54, wherein the method comprises the
following steps:
(i) introducing the compound into the subject;
(ii) imaging (e.g., a part of, the whole of) the subject using positron emission (e.g., PET).
A compound according to any one of claims 1 to 49, for use in a method of diagnosis or prognosis.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of protein aggregates in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates in a subject. A compound according to claim 56, for use in a method of diagnosis or prognosis of Alzheimer's disease (AD), Parkinson's disease (PD), or Huntington's disease in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder involving dis-regulation of a GABAA receptor in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of epilepsy, schizophrenia, or a mood disorder (e.g., anxiety) in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of metal overdose or metal poisoning in a subject.
A compound according to claim 56, for use in a method of diagnosis or prognosis of a disease or disorder associated with metal-induced leakiness of the blood- brain barrier in a subject.
Use of a compound according to any one of claims 1 to 49 in the manufacture of a medicament for use in a method of diagnosis or prognosis.
Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of protein aggregates in a subject.
Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals in a subject.
Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates in a subject.
70. Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of Alzheimer's disease (AD),
Parkinson's disease (PD), or Huntington's disease in a subject. 71 . Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder involving dis-regulation of a GABAA receptor in a subject.
72. Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors in a subject.
73. Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of epilepsy, schizophrenia, or a mood disorder (e.g., anxiety) in a subject.
74. Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of metal overdose or metal poisoning in a subject.
75. Use of a compound according to claim 66, in the manufacture of a medicament for use in a method of diagnosis or prognosis of a disease or disorder associated with metal-induced leakiness of the blood-brain barrier in a subject.
76. A method of diagnosis or prognosis of a disease or disorder in a subject which employs a compound according to any one of claims 1 to 49.
77. A method according to claim 76, wherein the method comprises the
following steps:
(i) introducing the compound into the subject;
(ii) determining the presence and/or location and/or amount of the compound in the subject;
(iii) correlating the result of the determination made in (ii) with the presence, absence, or state of the disease or disorder.
78. A method according to claim 76 or 77, wherein the disease or disorder is a
disease or disorder involving deposition of protein aggregates.
79. A method according to claim 76 or 77, wherein the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals. 80. A method according to claim 76 or 77, wherein the disease or disorder is a
disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates. 81 . A method according to claim 76 or 77, wherein the disease or disorder is
Alzheimer's disease (AD), Parkinson's disease (PD), or Huntington's disease.
82. A method according to claim 76 or 77, wherein the disease or disorder is a
disease or disorder involving dis-regulation of a GABAA receptor.
83. A method according to claim 76 or 77, wherein the disease or disorder is a
disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors. 84. A method according to claim 76 or 77, wherein the disease or disorder is epilepsy, schizophrenia, or a mood disorder (e.g., anxiety).
85. A method according to claim 76 or 77, wherein the disease or disorder is metal overdose or metal poisoning.
86. A method according to claim 76 or 77, wherein the disease or disorder is a
disease or disorder associated with metal-induced leakiness of the blood-brain barrier. 87. A compound according to any one of claims 1 to 49, for use in a method of
therapeutic monitoring
88. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of protein aggregates in a subject undergoing said therapy.
89. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals in a subject undergoing said therapy. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates in a subject undergoing said therapy.
91 . A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for Alzheimer's disease (AD), Parkinson's disease (PD), or
Huntington's disease in a subject undergoing said therapy.
92. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving dis-regulation of a GABAA receptor in a subject undergoing said therapy. 93. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors in a subject undergoing said therapy.
94. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for epilepsy, schizophrenia, or a mood disorder (e.g., anxiety) in a subject undergoing said therapy.
95. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for metal overdose or metal poisoning in a subject undergoing said therapy.
96. A compound according to claim 87, for use in a method of therapeutic monitoring of a therapy for a disease or disorder associated with metal-induced leakiness of the blood-brain barrier in a subject undergoing said therapy.
97. Use of a compound according to any one of claims 1 to 49 in the manufacture of a medicament for use in a method of therapeutic monitoring (e.g., of a therapy for a disease or disorder in a subject undergoing said therapy). 98. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of protein aggregates in a subject undergoing said therapy. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals in a subject undergoing said therapy.
100. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates in a subject undergoing said therapy.
101. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for Alzheimer's disease (AD), Parkinson's disease (PD), or Huntington's disease (HD) in a subject undergoing said therapy.
102. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving dis-regulation of a GABAA receptor in a subject undergoing said therapy.
103. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors in a subject undergoing said therapy.
104. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for epilepsy, schizophrenia, or a mood disorder (e.g., anxiety) in a subject undergoing said therapy.
105. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for metal overdose or metal poisoning in a subject undergoing said therapy. 106. Use of a compound according to claim 97, in the manufacture of a medicament for use in a method of therapeutic monitoring of a therapy for a disease or disorder associated with metal-induced leakiness of the blood-brain barrier in a subject undergoing said therapy.
107. A method of therapeutic monitoring of a therapy for a disease or disorder in a subject undergoing said therapy which employs a compound according to any one of claims 1 to 49. 108. A method according to claim 107, herein the method comprises the
following steps:
(i) introducing the compound into the subject;
(ii) determining the presence and/or location and/or amount of the compound in the subject;
(iii) correlating the result of the determination made in (ii) with effect and/or effectiveness and/or progress of the therapy.
109. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder involving deposition of protein aggregates.
1 10. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals. 1 1 1. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder involving deposition of elevated levels of metals, presence of elevated levels of metals, and/or dis-regulated distribution of metals, associated with deposition of protein aggregates. 1 12. A method according to claim 107 or 108, wherein the disease or disorder is
Alzheimer's disease (AD), Parkinson's disease (PD), or Huntington's disease (HD).
1 13. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder involving dis-regulation of a GABAA receptor.
1 14. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder involving changes in the expression level or distribution pattern of GABAA receptors.
1 15. A method according to claim 107 or 108, wherein the disease or disorder is
epilepsy, schizophrenia, or a mood disorder (e.g., anxiety).
1 16. A method according to claim 107 or 108, wherein the disease or disorder is metal overdose or metal poisoning.
17. A method according to claim 107 or 108, wherein the disease or disorder is a disease or disorder associated with metal-induced leakiness of the blood-brain barrier.
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