PROCESS FOR THE PREPARATION OF A MACROCYCLE
The present invention relates to a new process for the preparation of macrocyclic HCV protease inhibitor compounds of the formula
H-X
wherein R1 is an amino protecting group and X is halogen.
Particularly the HCV protease inhibitor compound of the formula
has been nominated for preclinical development.
Key step in the synthesis of the macrocyclic compounds of formula XXII is a ring closing metathesis (RCM) reaction of a diene compound in the presence of a suitable ring closing metathesis catalyst.
According to PCT Publication WO 2005/037214 or PCT Publication WO 2007/015824 a diene compound of the formula
is subjected to RCM in the presence of a Nolan or Hoveyda catalyst
to form the macrocyclic ester of formula
The substitution of the hydroxy function is according the state of the art performed in a subsequent step.
It was found that the RCM as disclosed in the art suffer from a low performance of the reaction due to modest yields, low catalyst selectivity and the need to run the reaction with very low substrate concentrations, which translates into low efficiency and high costs.
Object of the present invention therefore was to find an improved process which is applicable on technical scale and which is able to overcome the disadvantages known in the art.
It was found that this object could be reached with the process of the present invention as outlined below.
The process for the manufacture of a macrocyclic compound of formula
wherein R1 is an amino protecting group and X is a halogen atom, comprises one or more of the steps
a) subjecting a diene compound of formula
wherein R1 and PG are amino protecting groups, R2 is Ci_4-alkyl and is X is halogen to ring closing metathesis reaction in the presence of a ruthenium (II) carbene complex catalyst to form a macrocyclic ester of the formula
wherein R1 and PG are amino protecting groups, R2 is Ci_4-alkyl and X is halogen;
b) hydro lyzing the macrocyclic ester of formula I and removing the protecting group PG to form the macrocyclic acid of the formula
wherein R1 is an amino protecting group and X is halogen;
c) forming the macrocyclic sulfonamide of formula
wherein R1 is an amino protecting group and X is halogen by coupling the macrocyclic acid of formula XX with cyclopropyl sulfonamide and d) treating the macrocyclic sulfonamide of formula XXI with a sodium base to form the macrocyclic compound of formula XXII.
The following definitions are set forth to illustrate and define the meaning and scope of the various terms used to describe the invention herein.
The term "amino protecting group" refers to any substituents conventionally used to hinder the reactivity of the amino group. Suitable amino protecting groups are described in Green T., "Protective Groups in Organic Synthesis", Chapter 7, John Wiley and Sons, Inc. ,1991, 309-385. Suitable amino protecting groups for R1 are Fmoc, Cbz, Moz, Boc, Troc, Teoc or Voc. Preferred amino protecting group, as defined for R1 is Boc. Suitable amino protecting group for PG is C1-6- alkylcarbonyl, arylcarbonyl or Ci_6-alkoxycarbonyl, but preferably benzoyl.
The term "halogen" refers to fluorine, chlorine, bromine and iodine. The preferred halogen as a rule is chlorine, while the preferred halogen for X is fluorine.
In a preferred embodiment the moiety of the formula
stands for
The term "Ci-6-alkyl", alone or in combination with other groups, refers to a branched or straight-chain monovalent saturated aliphatic hydrocarbon radical of one to six carbon atoms, preferably one to four carbon atoms. This term is further exemplified by radicals as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl and pentyl or hexyl and its isomers.
The term "C1-4-alkyl" as used in herein for R2 refers to a branched or straight-chain monovalent saturated aliphatic hydrocarbon radical of one to four carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, preferably to ethyl.
The term "C2-6-alkenyl", alone or in combination with other groups, refers to a branched or straight-chain monovalent unsaturated aliphatic hydrocarbon radical of two to six carbon atoms, preferably two to four carbon atoms. This term is further exemplified by radicals as vinyl, propenyl, butenyl, pentenyl and hexenyl and their isomers. Preferred alkenyl radical is vinyl.
The term "C2-6-alkynyl", alone or in combination with other groups, refers to a branched or straight-chain monovalent unsaturated aliphatic hydrocarbon radical of two to six carbon atoms, preferably two to four carbon atoms. This term is further exemplified by radicals as ethynyl, propynyl, butynyl, pentynyl or hexynyl their isomers.
The term "halogen-Ci_6-alkyl" refers to a halogen substituted Ci_6-alkyl radical wherein halogen has the meaning as above. Preferred "halogen-Ci_6-alkyl" radicals are the fluorinated Ci_ 6-alkyl radicals such as CF3, CH2CF3, CH (CF3)2, CH (CH3) (CF3), C4F9. The term "Ci-6-alkoxy" refers to a branched or straight-chain monovalent saturated aliphatic hydrocarbon radical of one to six carbon atoms, preferably 1 to 4 carbon atoms attached to an oxygen atom. Examples of "alkoxy" are methoxy, ethoxy, propoxy, isopropoxy, butoxy,
isobutoxy, tert-butoxy and hexyloxy. Preferred are the alkoxy groups specifically exemplified herein.
The alkyl chain of the alkoxy group can optionally be substituted, particularly mono-, di- or tri-substituted by alkoxy groups as defined above, preferably methoxy, or ethoxy or by aryl groups, preferably phenyl. Preferred substituted alkoxy group is the benzyloxy group.
The term "Ci-6-alkyl carbonyl" refers to Ci_6-alkyl substituted carbonyl group, preferably to a Ci_4-alkycarbonyl group. It includes for example acetyl, propanoyl, butanoyl or pivaloyl. Preferred alkyl carbonyl group is acetyl.
The term "Ci-6-alkylthio" refers to the group Ci_6-alkyl-S-, preferably Ci_4-alkyl e.g. methylthio or ethylthio. Preferred are the alkylthio groups specifically exemplified herein.
The term "arylthio" refers to a group aryl-S-, preferably to phenylthio.
The term "Ci-6-alkylsulfonyl" refers to a Ci_6-alkyl substituted sulfonyl group, preferably to methylsulfonyl.
The term "Ci-6-alkylsulfϊnyl" refers to a Ci_6-alkyl substituted sulfϊnyl group, preferably to methylsulfinyl.
The term "SO2- aryl" refers to a sulfonyl substituted aryl radical. Preferred SO2-aryl radical is Sθ2-phenyl.
The term "SO2-NR R' ' " refers to a sulfonyl group substituted with an amino group NR R' ' wherein R' and R" independently of each other have the meaning of hydrogen or Ci-6-alkyl or R' and R' ' together with the N atom form a carbocycle, eg. - (CH2)4- or -(CH)4-. Preferred SO2- NR R" radical is SO2-N (CH3)2.
The term "mono- or di-Ci_6-alkyl-amino" refers to an amino group, which is mono- or disubstituted with Ci_6-alkyl, preferably Ci-4-alkyl. A mono-Ci_6-alkyl-amino group includes for example methylamino or ethylamino. The term "di-Ci_6-alkyl-amino" includes for example dimethylamino, diethylamino or ethylmethylamino. Preferred are the mono- or di-Ci-4- alkylamino groups specifically exemplified herein. It is hereby understood that the term "di-Ci_6- alkyl-amino" includes ring systems wherein the two alkyl groups together with the nitrogen atom to which they are attached form a 4 to 7 membered heterocycle which also may carry one further hetero atom selected from nitrogen, oxygen or sulfur.
The term "cycloalkyl" denotes a "C3_7-cycloalkyl" group containing from 3 to 7 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl.
The term "aryl" relates to the phenyl or naphthyl group, which can optionally be mono-, di-, tri- or multiply- substituted by halogen, hydroxy, CN, halogen-Ci-6-alkyl, NO2, NH2, N(H,alkyl), N(alkyl)2, carboxy, amino carbonyl, alkyl, alkoxy, alkylcarbonyl, Ci_6-alkylsulfonyl, SO2-aryl, SO3H, SCValkyl, SO2-NR5R", aryl and/or aryloxy. Preferred aryl group usually is phenyl, however the preference for aryl may differ as indicated hereinafter for certain substituents.
The term "aryloxy" relates to an aryl radical attached to an oxygen atom. The term "aryl" has the meaning as defined above. Preferred aryloxy group is phenyloxy.
The term "arylalkyl" relates to an aryl radical attached to an alkyl group. The term "aryl" has the meaning as defined above. Preferred arylalkyl group is benzyl.
The term "arylcarbonyl" relates to an aryl radical attached to a carbonyl group. The term "aryl" has the meaning as defined above. Preferred arylcarbonyl group is benzoyl.
The term "heteroaryl" relates to a heterocyclic aryl radical containing 1 to 3 heteroatoms in the ring with the remainder being carbon atoms. Suitable heteroatoms include, without limitation, oxygen, sulfur, and nitrogen. Exemplary heteroaryl groups include furanyl, thienyl, pyridyl, pyrrolyl, N-alkyl pyrrolo, pyrimidyl, pyrazinyl, imidazolyl, benzofuranyl, quinolinyl, and indolyl. Like the aryl group the heteroaryl group can optionally be mono-, di-, tri- or multiply- substituted by halogen, hydroxy, CN, NO2, NH2, N(H,alkyl), N(alkyl)2, carboxy, amino carbonyl, alkyl, alkoxy, alkylcarbonyl, Ci_6-alkylsulfonyl, SO2-aryl, SO3H, Sθ3-alkyl, SO2-NR5R' ' , aryl and/or aryloxy.
The diene starting compound of formula XV can be prepared following the scheme 1 below:
For example the vinylcyclopropanecarboxylate X is treated with sulfuric acid to form XI, then coupled with Boc-(2S,4R)-hydroxyproline to form XII. Carbamate formation at the free OH group with 4-fluoroisoindoline leads to XIII and removal of the Boc-protecting group and addition of the (5)-2-tert-Butoxycarbonylamino-non-8-enoic acid side chain can then provide diene XV.
The introduction of the N-substitution and the formation of the diene of formula II can be accomplished according to scheme 2 below:
Scheme 2:
For example diene XV is treated with a carboxylic acid anhydride in the presence of an alkali or alkali earth halogenide such as lithium chloride to introduce Ci-6-alkylycarbonyl substituents like acetyl or with a dialkyl dicarbonate in the presence of a base such as with 4-dimethylamino pyridine to introduce Ci-6-alkoxycarbonyl substituents like Boc.
The diene compounds of the formula
wherein R1 and PG are amino protecting groups, R2 is Ci_4-alkyl and is X is halogen are compounds not known in the art and accordingly represent a further embodiment of the present invention.
Preferred are diene compounds of formula II wherein R1 is Boc, R2 is ethyl; PG is
Ci-
6-alkylcarbonyl, arylcarbonyl or Ci_
6-alkoxycarbonyl and the moiety of the formula
stands for
Even more preferred is a diene compound of formula II wherein PG is benzoyl.
Step a) requires the transformation of the diene compound of formula II via RCM reaction into the macrocyclic ester of formula I.
The RCM reaction is as outlined above performed with a ruthenium (II) carbene complex catalyst selected from compounds of the formula
g
wherein L, L1 and L2 are neutral ligands;
X1 and X2 independently of each other are anionic ligands;
Y is hydrogen, C1-6-alkyl, C2-6- alkenyl or aryl, or Y and R8 taken together to form a (CH=CR) - or a -(CH2)J1- bridge with n having the meaning of 2 or 3 and R is as defined for R4;
Y1 and Y2 independently of each other are hydrogen, C1-6-alkyl, C2-6-alkenyl, C2-6-alkynyl, Ci_6-alkylthio, aryl, arylthio, Ci_6-alkylsulfonyl, Ci_6-alkylsulfinyl,
or
Y
1 and Y
2 taken together form a cycle of the type
with G being hydrogen or aryl;
or
Y Λ and j Y together form a cumulenyl group of type
VIb VIc
Y3 is hydrogen, Ci_6-alkyl, Ci-6-alkylsulfonyl, Ci_6-alkylsulfϊnyl;
Y4 and Y5 independently of each other is hydrogen, Ci-6-alkyl, C3_8-cycloalkyl,
C2-6-alkenyl, C2-6-alkynyl, Ci_6-alkoxy, C2-6-alkenyloxy, C2-6-alkynyloxy, aryloxy, Ci-6-alkoxycarbonyl, Ci_6-alkylthio, aryl, arylthio, Ci-6-alkylsulfonyl, Ci-6-alkylsulfϊnyl;
Ral, Ra2 and Ra3 independently of each other are C1-6-alkyl, C3-7-cycloalkyl, aryl, heteroaryl or Raland Ra2 or Ra2 and Ra3 or Ral and Ra3 form together a 1,5-bridged cyclooctyl group ;
Rb is Ci-6-alkyl, C2-6-alkenyl, halogen- Ci_6-alkyl, C2-6-alkynyl, aryl,
Ci-6-alkoxycarbonyl, Ci_6-alkylcarbonyl, mono-Ci_6-alkyl-or di-Ci_6-alkylamino, Ci-6-alkylaminocarbonyl, Ci_6-alkylthiocarbonyl, Ci-6-alkylsulfonyl, Ci_6-alkylsulfϊnyl or arylalkyl;
R3, R4, R5, R6, R7 and R8 independently of each other have the meaning of hydrogen, C1-6- alkyl, halogen-Ci-6-alkyl, C2-6-alkenyl, C2-6-alkynyl, halogen-Ci_6-alkyl, Ci_6-alkoxy, C2-6-alkenyloxy, C2-6-alkynyloxy, Ci_6-alkylcarbonyl, aryl, hydroxy, aryloxy, nitro, Ci-6-alkoxycarbonyl, amino, mono-Ci_6-alkyl-or di-Ci_6-alkylamino, halogen, thio, Ci-6-alkylthio, arylthio, Ci-6-alkylsulfonyl, Ci_6-alkylsulfinyl, arylsulfonyl, SO3H, Ci-6-alkylcarbonyl amino, aryl carbonyl amino, Ci_6-alkyl sulfonyl amino, aryl sulfonyl amino, halogen-Ci_6-alkyl sulfonyl amino, SO3-Ci_6-alkyl or OSi(Ci.6-alkyl)3 and SO2-NR R' '
wherein R' and R" independently of each other have the meaning of hydrogen, aryl or Ci_6-alkyl or R' and R' ' together with the N atom form a carbocycle;
a, b, c and d independently of each other have the meaning of hydrogen, Ci-6-alkyl, halogen-Ci-6-alkyl, C2-6-alkenyl, C2-6-alkynyl, halogen-Ci_6-alkyl, Ci-6-alkoxy, C2-6-alkenyloxy, C2-6-alkynyloxy, Ci-6-alkylcarbonyl, aryl, hydroxy, aryloxy, nitro, Ci-6-alkoxycarbonyl, amino, mono-Ci_6-alkyl-or di-Ci_6-alkylamino, halogen, thio, Ci-6-alkylthio, arylthio, Ci-6-alkylsulfonyl, Ci_6-alkylsulfinyl, arylsulfonyl, SO3H, Ci-6-alkylcarbonyl amino, aryl carbonyl amino, Ci_6-alkyl sulfonyl amino, aryl sulfonyl amino, halogen-Ci-6-alkyl sulfonyl amino, Sθ3-Ci_6-alkyl or OSi(Ci-6-alkyl)3 and SO2-NRR" wherein R' and R" independently of each other have the meaning of hydrogen, aryl or Ci_6-alkyl or R' and R' ' together with the N atom form a carbocycle;
Arene stands for phenyl or naphthyl optionally mono-, di-, tri- or multiply-substituted by halogen, hydroxy, cyano, halogen-Ci_6-alkyl, NO2, amino, mono-Ci-6-alkyl-or di-Ci_6- alkylamino, carboxy, amino carbonyl, Ci_6-alkyl, Ci-6-alkoxy, Ci-6-alkylcarbonyl, C1-O- alkylsulfonyl, aryl, aryloxy SO2-aryl, SO3H, SO3- Ci-β-alkyl , SO2-NR'R"wherein R and R" independently of each other are hydrogen or C^-alkyl;
Rla is hydrogen, hydroxy, Ci-6-alkyl, Ci_6-alkoxy, C2-6-alkenyloxy, C3_8-cycloalkyloxy, halogen- Ci_6-alkyloxy, aryl, aryloxy, Ci_6-alkylthio, arylthio, or -NR R wherein R and R independently of each other are hydrogen, d-6-alkyl, C3_8-cycloalkyl, aryl, aryl-Ci_6-alkyl or wherein R and R together with the N atom form a 5 to 8 member carbocycle which may contain nitrogen, oxygen or sulfur as additional hetero atom;
R2a and R3a are independently of each other H, C^-alkyl, C3_s-cycloalkyl, aryl, C7-18- arylalkyl or
Rla and R2a or R3a together form a 5 to 12 member carbocycle
The ligand L is a neutral ligand preferably selected from
— P(Ra1)(Ra2)(Ra3) .
VII • VIII • IX
wherein R10 and R11 independently of each other are Ci-6-alkyl, aryl, C2-6- alkenyl or 1-adamantyl and
R9a d are independently of each other hydrogen, Ci_6-alkyl, C2-6-alkenyl or aryl, or R9b and R9c or R9a and R9d taken together form a-(CH2)4-bridge;
or R9a and R9d in formula IX both have the meaning of halogen, preferably of chlorine;
Ral a3 are as outlined above, but preferably cyclohexyl or phenyl.
In a preferred embodiment R10 and R11 are Ci-6-alkyl or a phenyl group which is mono-, di- or tri- substituted with Ci_6-alkyl.
R10 and R11 more preferably have the meaning of t-butyl, 1-adamantyl, isopropyl, 2-methylphenyl, 2, 6-diisopropylphenyl or 2, 4, 6-trimethylphenyl, most preferably 2, 4, 6-trimethylphenyl.
In a preferred embodiment R9a and R9c are methyl or phenyl and R9b and R9d are hydrogen, or R9a and R9c or R9b and R9d are taken together to form a -(CH2)J1- bridge with n having the meaning of 3 or 4. Its herby understood that if chiral carbon atoms are present, both the racemic and the enantiomerically pure form are comprised.
In a further preferred embodiment R9a d is hydrogen.
In a further preferred embodiment L is
Vila Villa
wherein R10 and R11 are as described above.
The anionic ligands X1 and X2 are preferably selected from a halogenide or a pseudo halogenide such as cyanide, a rhodanide, a cyanate, an isocyanate, acetate or trifluoro acetate may be selected.
Preferred anionic ligand for X1 and X2 is a halogenide, whereas chloro is the most preferred anionic ligand. Y preferably is hydrogen;
Y1 and Y2 are the same or different and preferably stand for hydrogen, d-β-alkyl, C2-6-alkenyl, Ci_6-alkylthio, phenyl, phenylthio, or
Y1 and Y2 taken together form a cycle of the type
with G being hydrogen or phenyl;
Y3 preferably is hydrogen.
Y4 and Y5 are the same or different and preferably stand for hydrogen, C^-alkyl, aryl or arylthio.
Rb is as outlined above, but preferably stands for Ci_6-alkyl and halogen-C1-6-alkyl.
The preferred meaning for a, b and d is hydrogen.
The preferred meaning for c is hydrogen, halogen, nitro, Ci_6-alkylcarbonyl amino, aryl carbonyl amino, aryl sulfonyl amino, alkyl sulfonyl amino, halogen-Ci_6-alkyl sulfonyl amino, SO2-NR R" wherein R' and R" independently of each other have the meaning of hydrogen, C1- 6-alkyl, aryl or R' and R" together with the N atom form a carbocycle.
More preferred c means hydrogen, Cl, nitro, SO2-NR5R".
Preferred meaning for Arene is benzene, p-cymene, mesitylene or, p-xylene.
The following catalysts represent preferred ruthenium (II) carbene complex catalysts
Even more preferred are: [RuCl2(PCy3)(ImH2Mes)(benzylidene)], [RuCl2C=CH(I-IPrOPh))(ImH2MeS)], [RuCl2(PCy3)(ImH2Mes)(3 -phenylindenyl- 1 -idene)] , [RuCl2(3-phenylindenyl-l-idene)(ImMes)(PCy3)],
[RuC^=CH(O-OCH(Me)CO2Me)PhXImH2MeS)],
[RuCl2C=CH(O-OCH(Me)CONEt2)Ph)(ImH2MeS)], [RuCl2(=CH(o-OCH(Me)CO-N-Morpholine)Ph)(ImH2Mes)],
[RuCl2(=CH(o-OCH(Me)CO-N-Pyrrolidine)Ph)(ImH2Mes)], [RuCl2(=CH(o-OCMe2CO-N-Pyrrolidine)Ph) (ImH2MeS) ] and
[RuCl2(=CH(o-OCH2CO-N-Pyrrolidine)Ph)(ImH2Mes)] .
The RCM reaction is usually performed in an organic solvent, preferably in an aromatic organic solvent such as in benzene, toluene or mesitylene or in halogenated aromatic solvents such as in polyfluorinated benzenes or toluenes like α,α,α-trifluoro toluene, octafluoro toluene, 1 ,2-difluorobenzene or hexafluoro benzene. Also halogenated hydrocarbons such as dichloromethane or dichloro ethane are suitable solvents. The solvents may be used as single solvent or as a mixture of different solvents. In addition a co-solvent selected from an aliphatic hydrocarbon such as pentane, hexane or heptane may be used as well.
The reaction temperature is as a rule selected in a range of 200C to 1400C, preferably 400C to 1000C and even more preferred 500C to 900C.
The molar substrate to catalyst ratio S/C is usually selected in a range of 20 to 10000, but preferably in a range of 150 to 4000.
The exact substrate concentration is not critical, it can be chosen in a very wide range between 0.1 and 25%. From a technical standpoint it is preferable to use a substrate concentration between 5 and 15%.
It is convenient to run the reaction either under bubbling of an inert gas through the reaction mixture or under a slight vacuum.
The macrocyclic ester of formula I can be isolated by applying methods known to the skilled in the art such as by column chromatography or by crystallization. The metathesis reaction mixture can also, after a simple extractive work-up, be brought directly into the next step.
In order to remove most catalyst from the solution of the macrocyclic ester I the reaction mixture can be treated with a complexing agent such as ethylenediamine and to extract the resulting soluble ruthenium species into acidic water. The amount of ethylenediamine is not critical; it can be used in a 1 :1 to 100: 1 molar ratio relative to the catalyst, preferentially in 20: 1 to 70 : 1 mo lar ratio .
The macrocyclic esters of the formula
wherein R1 and PG are amino protecting groups, R2 is Ci_4-alkyl and X is halogen are compounds not known in the art and thus represent a further embodiment of the present invention.
In a preferred macrocyclic ester of formula I R
1 is Boc, R
2 is ethyl, PG is C
1-6- alkylcarbonyl, arylcarbonyl or Ci_
6-alkoxycarbonyl and the moiety of the formula
stands for
In a further preferred macrocyclic ester of formula I PG is benzoyl.
Step b) requires the hydrolysis of the ester and the removal of the protection group PG of the macrocyclic ester of formula I and the formation of the macrocyclic acid of formula XX.
In a preferred embodiment the macrocyclic ester of the formula
wherein R
1 is Boc, R
2 is ethyl, PG is d-6-alkylcarbonyl, arylcarbonyl or C
1-6- alkoxycarbonyl and the moiety of the formula
stands for
is used. In an even more preferred embodiment PG is benzoyl.
The hydrolysis and the removal of the protection group PG can usually be accomplished by treatment with an aqueous alkali hydroxide solution such as with an aqueous sodium hydroxide solution in solvents like tetrahydrofuran, methanol or ethanol or mixtures thereof at a temperature of 00C to 400C.
In the case of PG = Ci_6-alkoxycarbonyl its removal can usually be accomplished by treatment with an acid, such as with hydrochloric acid, sulfuric acid, trifluoro acetic acid, methanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid. As the acid treatment may remove the Boc-group R1 as well reintroduction of this Boc group R1 may be necessary for performing the subsequent synthesis steps.
After neutralization of the reaction mixture, usually with hydrochloric acid, the macrocyclic acid of formula XX can be isolated by way of extraction with a suitable solvent such as with dichloromethane. Crystallization in a suitable solvent, preferably in tetrahydrofuran leads to a crystalline product with a purity of over 98 % (HPLC, area).
In a further preferred embodiment of the invention the macrocyclic acid of formula XX can be obtained directly without isolation of the intermediate products from the intermediate of formula XIVa.
Scheme 3:
XIVa XX
R . 1 , R r> 2 and X have the meaning as mentioned above.
Step c) requires the coupling of the macrocyclic acid of formula XX with cyclopropyl sulfonamide to form the macrocyclic sulfonamide of formula XXI.
In a preferred embodiment the macrocyclic acid of the formula
is used.
In a first step the macrocyclic acid of formula XX is reacted with acetic acid anhydride in the presence of an inorganic base, such as with an alkali carbonate like sodium carbonate and a suitable organic solvent such as with tetrahydrofuran into an azlactone intermediate of the formula
wherein R1 is an amino protecting group and X is halogen.
The reaction is expediently performed at a temperature of 100C to 500C.
As a rule the azlactone intermediate will not be isolated but in situ further reacted with cyclopropyl sulfonamide in the presence of an inorganic base, such as with an alkali carbonate like potassium carbonate to the macrocyclic sulfonamide of formula XXI.
The reaction in this second step is expediently performed at a temperature of 500C to 700C.
Upon completion of the reaction the reaction mixture can be treated with water. After separation and removal of the water phase the organic phase may further be diluted with a suitable organic solvent such as with ethyl acetate or toluene and washed e.g. with an aqueous sulphuric acid and water.
Isolation of the macrocyclic sulfonamide of formula XXI can then be accomplished by a solvent switch to ethanol followed by addition of the ethanolic solution to water thereby causing precipitation of the desired product.
However, in a preferred embodiment the macrocyclic sulfonamide of formula XXI will not be isolated, but the organic phase which has been treated as hereinbefore described will be freed of residual water by way of a continuous azeotropic distillation.
The mixture can then directly be used for subsequent step d).
Step d) requires the treatment of the macrocyclic sulfonamide of formula XXI with a sodium base to form the end product, i.e. the macrocyclic compound of formula XXII.
In a preferred embodiment the macrocyclic sulfonamide of the formula
is used.
As a rule the water free mixture obtained from step c) is treated with a sodium base such as sodium hydroxide, preferably an aqueous solution thereof, sodium methylate or sodium ethoxide, preferably with sodium methylate in the presence of methanol at a temperature of 00C and 500C.
Upon completion of the reaction the reaction mixture can be treated with a mixture of a suitable organic solvent such as ethyl acetate and water where after the crystals of the sodium compound of formula XXII, preferably the compound of formula XXIIb can be collected in good purity and yield.
Examples
Abbreviations: r.t. = room temperature ImH2MeS = l,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene ImMes = l,3-bis-(2,4,6-trimethylphenyl)-2-imidazolylidene ImH2Pr = l,3-bis-(2,6-diisopropylphenyl)-2-imidazolidinylidene RCM = ring closing metathesis S/C = molar substrate-to-catalyst ratio Mes = 2,4,6-Trimethylphenyl a% = HPLC area%
Diene XV: 4-Fluoro-l,3-dihydro-isoindole-2-carboxylic acid, (3i?,55)-l-[(5)-2-tert-butoxy- carbonylamino-non-8-enoyl]-5-[(li?,25)-l-ethoxycarbonyl-2-vinyl-cyclopropylcarbamoyl]- pyrrolidin-3-yl ester.
N-acetyl-Diene lib: 4-Fluoro-l,3-dihydro-isoindole-2-carboxylic acid (3i?,55)-5-[acetyl- ((li?,25)-l-ethoxycarbonyl-2-vinyl-cyclopropyl)-carbamoyl]-l-((lS)-2-tert-butoxycarbonylamino- non-8-enoyl)-pyrrolidin-3-yl ester
N-propionyl-Diene Hc: 4-Fluoro-l,3-dihydro-isoindole-2-carboxylic acid (3i?,55)-l-((5)-2-tert- butoxycarbonylamino-non-8-enoyl)-5-[((li?,25)-l-ethoxycarbonyl-2-vinyl-cyclopropyl)- propionyl-carbamoyl]-pyrrolidin-3-yl ester
N-BOC -Diene Ha: 4-Fluoro-l,3-dihydro-isoindole-2-carboxylic acid (3R,55)-l-((iS)-2-tert- butoxycarbonylamino-non-8-enoyl)-5-[tert-butoxycarbonyl-((li?,25)-l-ethoxycarbonyl-2-vinyl- cyclopropyl)-aminocarbonyl]-pyrrolidin-3-yl ester
N-Benzoyl-Diene Hd:
4-Fluoro-l,3-dihydro-isoindole-2-carboxylic acid (3i?,55)-5-[benzoyl-((li?,25)-l- ethoxycarbonyl-2-vinyl-cyclopropyl)-carbamoyl]-l-((5)-2-tert-butoxycarbonylamino-non-8- enoyl)-pyrrolidin-3-yl ester
N-Acetyl-RCM-Ester Ib: (Z)-(15',4i?,65',14lS',18i?)-3-Acetyl-14-tert-butoxycarbonylamino-18-(4- fluoro- 1 ,3-dihydro-isoindole-2-carbonyloxy)-2, 15-dioxo-3 , 16-diaza- tricyclo[14.3.0.04'6]nonadec-7-ene-4-carboxylic acid ethyl ester.
The atom numbering is shown below:
Ib
N-Propionyl-RCM-Ester Ic:
(Z)-(1S,4R,6S,14S, 18i?)-14-tert-Butoxycarbonylamino- 18-(4-fluoro- 1 ,3-dihydro-isoindole-2- carbonyloxy)-2,15-dioxo-3-propionyl-3,16-diaza-tricyclo[14.3.0.04'6]nonadec-7-ene-4- carboxylic acid ethyl ester.
N-BOC- RCM-Ester-Ia:
(Z)-(1S,4R,6S, 14S, 1 SR)- 14-tert-Butoxycarbonylamino- 18-(4-fluoro- 1 ,3-dihydro-isoindole-2- carbonyloxy)-2,15-dioxo-3,16-diaza-tricyclo[14.3.0.04'6]nonadec-7-ene-3,4-dicarboxylic acid 3- tert-butyl ester 4-ethyl ester.
N-Benzoyl-RCM-Ester Id:
(Z)-(I S,4R,6S, 14S, 18i?)-3-Benzoyl- 14-tert-butoxycarbonylamino- 18-(4-fluoro- 1 ,3-dihydro- isoindole-2-carbonyloxy)-2,15-dioxo-3,16-diaza-tricyclo[14.3.0.04'6]nonadec-7-ene-4-carboxylic acid ethyl ester.
RCM-Carboxylic Acid XXb:
(Z)-(I S,4Λ,6S, 14S, 1 ZR)- 14-tert-Butoxycarbonylamino- 18-(4-fluoro- 1 ,3-dihydro-isoindole-2- carbonyloxy)-2,15-dioxo-3,16-diaza-tricyclo[14.3.0.04'6]nonadec-7-ene-4-carboxylic acid.
RCM-Ester XVI:
(Z)-( 1S,4R,6S, 1 AS, 1 %R)- 14-tert-Butoxycarbonylamino- 18-(4-fluoro- 1 ,3-dihydro-isoindole-2- carbonyloxy)-2,15-dioxo-3,16-diaza-tricyclo[14.3.0.04'6]nonadec-7-ene-4-carboxylic acid ethyl ester.
Table of Catalysts tested:
a) Commercially available from Sigma- Aldrich Chemie GmbH, Postfach, CH-9471 Buchs, Switzerland: b) Commercially available from Zannan Pharma Ltd. 4299 Jindu Road, Bid. 3, Shanghai, 201108, P.R. China and Strem Chemicals Inc., 7 Mulliken Way, Newburyport, MA 01950-4098, USA. c) Commercially available from Umicore & Co., Rodenbacher Chaussee 4, D-63403 Hanau, Germany and Strem Chemicals Inc., 7 Mulliken Way, Newburyport, MA 01950-4098, USA. d) Commercially available from Degussa AG, Rodenbacher Chaussee 4, D-63403 Hanau, Germany. e) Prepared according to WO2008/000644 Al.
f) Prepared according to EP Appl. No. 08154367.0, filed April 11, 2008. g) Commercially available from Strem Chemicals, Inc., Postfach 1215, KEHL, 77672, Germany.
Preparation of diene compounds Ha to Hd: Example A
To a solution of the diene XV (40.0 g, 53.80 mmol, 92.1% content) in 330 ml of tetrahydrofuran were added under argon 22.70 ml (163.5 mmol) of triethylamine, 6.90 g (161.6 mmol) of lithium chloride and 15.0 ml (159 mmol) of acetic anhydride and the mixture was stirred at 600C (internal temperature) during 6 h, after which time only 2 area% of diene XV had remained unreacted. The slightly cloudy reaction mixture was cooled, filtered and the precipitate washed with tetrahydrofuran.. The combined filtrates were rotary evaporated to dryness (40°C/180 mbar). The oily residue was dissolved in 500 ml of ethyl acetate and extracted with 300 ml of hydrochloric acid 0.5 M. The aqueous phase was back-extracted with a total of 1 L ethyl acetate. The combined organic phases were washed with 300 ml of hydrochloric acid, 300 ml of deionized water, then dried with 70 g of sodium sulfate and filtered. The filtrate was treated with decolorizing charcoal, filtered and rotary evaporated. The oily residue was purified by column chromatography (1 kg silica gel 0.040-0.063 mm) and eluted with a mixture of heptane and ethyl acetate using a gradient from 9:1 to 3:2. Collection of the fractions containing the desired product in comparable purity and evaporation to dryness to constant weight (40°C/16 mbar/3 h) afforded 27.6 g of diene-acetate lib as a white solid with 96 area% according to HPLC and 85% according to NMR.
HPLC method: same as Example 1. Retention times: diene XV 8.66 min, diene-acetate lib 10.1 min. MS [MH]+ 657.4 u, 727.4 [MNH4J+.
NMR (selected peaks, δ, CDCl3): (CH3C=O) 2.26 (s, 3H), (CH3-CH2) 1.22 (t, 3H), (CH3-CH2J
4.13 (m, 2H), (t-Bu) 1.33 (s, 9H).
IR: Carbonyl signals at 1710 cm'1 (strong, broad), 1632 cm'1 (medium, broad).
Example B
To a solution of the diene XV (15.3 g, 22 mmol) in 120 ml of tetrahydrofuran were added under argon 6.8 g (67 mmol) of triethylamine, 2.9 g (67 mmol) lithium chloride and 6.4 g (49 mmol) of propionic acid anhydride. The mixture was heated to 800C for 10 h 30 min and then cooled to room temperature at which it was stirred for another H h. After this time in-process control showed 99.6 % (HPLC) conversion. To the mixture 100 mL water and 3.5 mL aqueous HCl (37%) were added. The biphasic mixture was extracted with ethyl acetate, the aqueous layer was separated off and the organic layer was washed with 100 mL of brine. The aqueous layers were back extracted with 200 mL of ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated to dryness. 26.8 g of an oily brown residue was obtained. The oily residue was purified by column chromatography (600 g silica gel 0.040-0.063 mm) and eluted with a mixture of hexane and ethyl acetate using a gradient from 7:3 to 7:4. Collection of the fractions containing the desired product in comparable purity and evaporation to dryness afforded 16.8 g of Hc as a colorless solid with a purity of 97.6 area % according to HPLC.
HRMS, [MH]+ 785.41315.
NMR (δ, DMSO-D6, 1500C): 1.09 (t, 3H), 1.15 (t, 3H), 1.30 (s, 9H), 1.3-1.4 (m, 6H), 1.52 (m, IH), 1.60-1.69 (m, IH), 1.74-1.82 (m, IH), 1.92-1.95 (m, IH), 1.99-2.04 (m, 2H), 2.21-2.27 (m, IH), 2.41 (m, IH), 2.48-2.56 (m, IH), 2.61-2.71 (m, IH), 3.81 (m, IH), 3.89 (d, br, IH), 4.09 (q, 2H), 4.17 (q, br, IH), 4.66 (s, 4H), 4.90 (m, IH), 4.96 (m, IH), 5.14 (m, IH), 5.16-5.33 (m, 3H), 5.74-5.85 (m, 2H), 6.0 (s, br, IH), 7.01 (M, IH), 7.11 (d, IH), 7.30 (m, IH). IR (selected absorptions, cm 1): 3294, 2980, 2934, 1705, 1631, 1596, 1518, 996, 911, 776.
Example C:
To a solution of the diene XV (15.3 g, 22 mmol) in 90 ml of ethyl acetate were added under argon 0.82 g (6.7 mmol) of 4-dimethylamino pyridine. The mixture was cooled to 00C and 6.9 g (31 mmol) of di-tert-butyl dicarbonate were added within 5 minutes. The reaction mixture was heated to 23°C an stirred at this temperature for 225 minutes. After this time only 3.8 area% of diene XV had remained unreacted. To the mixture 50 mL of 0.1 N aqueous HCl were and 50 mL of ethyl acetate were added. The aqueous phase was separated and extracted with 100 mL of ethyl acetate. The organic layer was washed with 50 mL of water, dried over sodium sulfate, filtered and concentrated. 21.1 g of a brown oily residue was obtained. The oily residue was purified by column chromatography (silica gel 0.040-0.063 mm) and eluted with a mixture of hexane and ethyl acetate using a gradient from 8:2 to 7:3. Collection of the fractions containing the desired product in comparable purity and evaporation to dryness afforded 17.3 g of N-BOC- diene Ha as a yellowish solid with 98.5 area% according to HPLC. HRMS, [MHJ+ 785.41315.
NMR (δ, DMSO-D6, 1200C): 1.15 (t, 3H), 1.28 (s, 9H), 1.25-1.40 (m, 6H), 1.47 (s, 9H), 1.52 (m, IH), 1.62 (m, IH), 1.79 (m, IH), 2.01 (m, 2H), 2.23 (m, IH), 2.29 (m, IH), 1.48-2.55 (m, 2H), 3.82 (m, IH), 4.0 (m, IH), 4.06 (m, 2H), 4.14 (m, IH), 4.66 (s, 4H), 4.90 (m, IH), 5.30 (m, 6H), 5.78 (m, 2H), 6.25 (s, br, IH), 7.03 (m, IH), 7.12 (d, IH), 7.31 (m, IH). IR (selected absorptions, cm 1): 3289, 1719, 1634, 1523, 1019, 997, 776.
XV Md
To a solution of the diene XV (30.0 g, 41.67 mmol) in 200 ml of toluene were added under argon in an ice bath 7.20 ml (79.2 mmol) of benzoyl chloride. Then a 2 M solution of lithium tert- butoxyde in tetrahydrofuran (38.5 ml, 77.0 mmol) was added within 5 minutes and the reaction mixture was stirred at the same temperature for 30 minutes. After this time only 4.6 area% of diene XV had remained unreacted. After dropwise addition of a 2 M sodium hydroxide solution (50 ml, 100 mmol) the organic phase was separated, extracted with 50 mL each of water, 1 M hydrochloric acid and water, dried with sodium sulphate and evaporated to dryness. The resulting brown oily residue was purified by column chromatography (silica gel 0.040-0.063 mm) and eluted with a mixture of heptane and ethyl acetate using a gradient from 3 : 1 to 1 : 1. Collection of the fractions containing the desired product in comparable purity and evaporation to dryness afforded 26.8 g (78.2%) of N-benzoyl-diene Hd as a yellowish solid with 96.0 area% according to HPLC. HRMS: [MH]+ 789.3858.
IR (nujol, cm 1, selected signals): 1708, 1640 (C=O)
RCM Examples:
Comparison example A (RCM with no N-substitution)
To a solution of 6.60 g (5.00 mmol) of diene XV (as a 51.4% solution in toluene) in 390 ml of toluene was added at 700C under vacuum (pressure = ca. 0.26 bar) by dropping funnel a solution of 3.59 mg (0.005 mmol) of catalyst 5058 in 20 ml of toluene. The catalyst was added during ca. 1 h. Under these conditions a small amount of toluene (19 ml) distilled off in the course of the reaction. After 2 h of total reaction time 17 μl (0.252 mmol) of ethylene diamine were added at ambient pressure, the reaction mixture was concentrated under vacuum, washed with 0.5 M aqueous solution of hydrochloric acid, treated with decolorizing charcoal and evaporated to dryness. RCM-ester XVI was isolated as an off-white solid (3.58 g) with 84.2 a% purity (75.7% content, 82.5% yield).
Example 1 (S/C 20)
In a glove-box (O2 < 2 ppm) a solution of 60.0 mg (0.070 mmol, corrected by content) of N- acetyl-diene lib and 2.32 mg (0.0035 mmol) of catalyst 5024 in 1.7 ml of toluene (washed with aqueous hydrochloric acid and distilled under argon) was stirred at 600C in a 15 ml screw- capped flask. After 1.5 h one drop of ethylenediamine was added and the mixture was stirred for ca. 30 min outside of the glove box. After addition of 1 ml of 1 M aqueous solution of hydrochloric acid the biphasic mixture was stirred for ca. 5 min. A 0.5 ml aliquote of the organic
phase was removed and evaporated to dryness; the oily residue was dissolved in 1 ml of acetonitrile and analyzed by HPLC. Conversion was 99.6 area%, the desired product (N-acetyl- RCM-ester Ib) had 89 area % purity.
HPLC method for the determination of conversion and selectivity: Waters XBridge Cl 8 column, 4.6 x 150 mm, solvent A: water/acetonitrile 95/5, solvent B: acetonitrile, solvent C: buffer Bu4N+ HSO4 ' pH 3 (1 g in 1 1 water/ acetonitrile 9:1), gradient from A/B/C 50/40/10 to 10/80/10 within 6.5 min, then 14 min isocratic, 400C, 210 nm, 1 ml/min. Retention times: toluene 6.0 min, diene- acetate lib 10.0 min, N-acetyl-RCM-ester Ib 8.65 min (identified by HPLC/MS, [MH]+ 699.4 u), peaks of dimeric by-products at 13.3, 13.8 and 15.6 min (HPLC-MS: [MH]+ 1396 and 1423 u). Only the sum of the dimer peaks is given in the tables and experiments.
Examples 2a-2o
The examples in Table 1 were carried out using the same procedure and conditions as in Example 1, but in the presence of various catalysts.
Table 1
In a glove-box (O2 < 2 ppm) a solution of 60.0 mg (0.070 mmol, corrected by content) of N- propionyl-diene Hc and 2.49 mg (0.0038 mmol) of catalyst 5024 in 1.7 ml of toluene (washed with aqueous hydrochloric acid and distilled under argon) was stirred at 600C in a 15 ml screw- capped flask. After 1.5 h one drop of ethylenediamine was added and the mixture was stirred for ca. 30 min outside of the glove box. After addition of 1 ml of 1 M aqueous solution of hydrochloric acid the biphasic mixture was stirred for ca. 5 min. A 0.5 ml aliquote of the organic phase was removed and evaporated to dryness; the oily residue was dissolved in 1 ml of acetonitrile and analyzed by HPLC. Conversion was >99.5 area%, the desired product (N- propionyl-RCM-ester Ic) had 86 area % purity.
HPLC method for the determination of conversion and selectivity: same as Example 1. Retention times: toluene 6.0 min, N-propionyl-diene Hc 10.7 min, N-propionyl-RCM-ester Ic 9.2 min (identified by HPLC/MS, [MH]+ 713.3 u), peaks of dimeric by-product at 17.4 min.
(MS: [MH]+ 1426.6 u), peaks of unknown by-products at 12.3 min (MS: 768), 14.0 and 16.7 (complex MS spectrum).
NMR: (δ, DMSO-D6, 1200C): 1.07 (t, 3H), 1.14 (t, 3H), 1.23 (s, 9H), 1.26-1.48 (m, 6H), 1.71- 1.80 (m, IH), 1.84-1.90 (m, 2H), 1.96-2.03 (m, IH), 2.11-2.23 (m, 2H), 2.34-2.44 (m, IH), 2.61- 2.68 (m, 2H), 2.70-2.82 (m, IH), 3.86 (m, IH), 4.02-4.22 (m, 5H), 4.66 (s, 4H), 5.08 (t, IH), 5.30 (m, 2H), 5.49 (m, IH), 6.22 (s, br, IH), 7.03 (m, IH), 7.12 (m, IH), 7.31 (m, IH). IR (selected absorptions, cm 1): 3286, 1711, 1627, 1523, 1366, 1249, 778.
Examples 4a-4o
The examples in Table 2 were carried out using the same procedure and conditions as in Example 3, but in the presence of various catalysts.
Table 2
Example 5: (S/C 533. cone, ca. 14%)
A solution of 15.7 g (20 mmol) of N-BOC-diene Ha in 115 ml of toluene was heated to 600C. At this temperature 14.3 mg of catalyst 5024 dissolved in 5.9 mL of toluene was dosed within 1 h to the reaction mixture; an in process control showed complete conversion after dosing was completed (Ha n.d.). During the reaction the mixture was purged with nitrogen (150 ml/min). To the reaction mixture 118 mg of ethylene diamine was added. It was cooled to room temperature and 40 mL of 0.5 N aqueous HCl were added. The phases there separated and the aqueous layer was extracted with 100 mL of toluene. The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated to dryness to obtain 18.5 g of raw product.
Purification was achieved by column chromatography (silica gel 0.040-0.063 mm) with a mixture of hexane and ethyl acetate using a gradient of 8:2 then 7:3 and 6:4. Fractions containing the desired product in comparable purity were collected, concentrated and recrystallized from ethyl acetate. Drying under reduced pressure afforded 11.6 g of colorless crystals (98.6 area %
HPLC) and 2.9 g of residue from concentrated mother liquor (95.5 area % HPLC) giving a yield of 93 %.
HRMS, [MH]+ 757.38174
NMR (selected peaks, δ, DMS-D6, 1200C): 1.15 (t, 3H), 1.24 (s, 9H), 1.29-1.46 (m, 6H), 1.49 (s, 9H), 1.62 (m, IH), 1.73 (m, 2H), 1.99-2.24 (m, 4H), 2.50-2.60 (m, 2H), 3.87 (m, IH), 4.06 (q,
2H), 4.17 (m, 2H), 4.67 (s, 4H), 5.20 (m, IH), 5.30 (m, IH), 5.33 (m, IH), 5.46 (m, IH), 6.20 (d, br, IH), 7.03 (m, IH), 7.12 (d, IH), 7.31 (m, IH).
IR (selected absorptions, cm"1): 3361, 1739, 1692, 1519, 1370, 1175, 792.
Example 6 (S/C 1000. cone. = 8%))
A solution of 5.00 g (6.67 mmol) of N-acetyl-diene lib in 70 ml of toluene was extracted twice with 15 ml HCl 0.5 mo 1/1 and rotary concentrated to a total weight of 40.2 g (corresponds to a 8% weight/weight concentration). To this solution was added at 700C under vacuum (pressure = ca. 0.26 bar) by dropping funnel a solution of 4.75 mg (0.0067 mmol) of catalyst 5058 in 10 ml of toluene. The catalyst was added during 1 h. Under these conditions a small amount of toluene
(ca 10 ml) distilled off in the course of the reaction. After 1.5 h of total reaction time 23 μl (0.34 mmol) of ethylenediamine were added at ambient pressure, the reaction mixture was concentrated under vacuum, washed with 0.5 M aqueous solution of hydrochloric acid, treated with 10 ml ethyl acetate and 0.41 g of charcoal and stirred for 30 min, filtered and evaporated to dryness. N- Acetyl- RCM-ester Ib was isolated as yellow foam (5.07 g).
HPLC analysis showed Ib (89.2 area%), 0.2 area% lib and 7.7 area% dimers (identified by HPLC/MS). The content by HPLC with internal standard was 83.5%, which corresponds to 90.8% yield. HPLC method for content determination: Gemini C6-Phenol column, 4.6 x 150 mm, 3.0 um, solvent A: water/acetonitrile 95/5, solvent B: buffer Bu4N+HSO4 " pH 3 (Ig in 1 1 water/acetonitrile 9:1); solvent C: acetonitrile gradient from A/B/C 25/5/70 to 15/5/80 within 1.0 min, then 4 min isocratic, 45°C, 210 nm, 2.3 ml/min. Retention times: N-acetyl-diene lib 1.88 min, N-acetyl-RCM Ib 2.18 min, int. standard dinitrobenzene (1 g/1 acetonitrile) 10.3 min. MS: [MH]+ 699.4; NMR (selected peaks, δ, CDCl3): (CH3C=O) 2.27 (s, 3H), (CH3-CH2) 1.23 (t, 3H), (CH3-CHJ2 4.14 and 4.22 (m, IH each), (t-Bu) 1.27 (s, 9H). IR: carbonyl absorption at 1705 cm 1 (strong, broad).
Example 7 (S/C 600. cone. = 1%)
To a solution of 1.0 g (1.35 mmol) of N-acetyl-diene lib in 114 ml of toluene was added at 700C under vacuum (pressure = ca. 0.26 bar) by dropping funnel a solution of 1.63 mg (0.0017 mmol) of catalyst 5058 in 4 ml of toluene. The catalyst was added during 1 h. Under these conditions a small amount of toluene (ca 14 ml) distilled off in the course of the reaction. After 2 h of total reaction time 10 μl (0.15 mmol) of ethylenediamine were added at ambient pressure, the reaction mixture was concentrated under vacuum, washed with 0.5 M aqueous solution of hydrochloric acid, stirred with 80 mg of charcoal for 30 min, filtered and evaporated to dryness. N-acetyl- RCM-ester Ib was isolated as white foam (1.07 g). HPLC analysis showed 2.2 area% toluene, 91.9 area% Ib, 1.5 area% lib and 1.0 area% dimers. The purity by HPLC with internal standard was 89.0%> content, which corresponds to 98% yield.
Examples 8a-8e
The experiments in Table 4 have been carried out in analogy to Example 7, Catalyst No., temperature, reaction time, yield and purity of N-acetyl-RCM ester Ib are given in the table.
Table 3
All reactions were run at S/C 1000 on a 7.0 mmol scale for 1.5 h. Concentration is 8%. %y. = % yield determined by HPLC with internal standard; a%: HPLC area%. $) 12% concentration.
Example 9 (S/C 1000. cone. = 8%))
To a solution of 5.83 g (7.00 mmol) of N-propionyl-diene Hc in 80 ml of toluene was added at 700C under vacuum (pressure = ca. 0.26 bar) by dropping funnel a solution of 5.26 mg (0.0070 mmol) of catalyst 5065 in 15 ml of toluene. The catalyst was added during 1 h, then the dropping funnel was rinsed with 15 ml of toluene. Under these conditions a small amount of toluene (ca 10 ml) distilled off in the course of the reaction. After 1.5 h of total reaction time 24 μl (0.35 mmol) of ethylenediamine were added at ambient pressure, the reaction mixture was concentrated under vacuum, washed with 0.5 M aqueous solution of hydrochloric acid, treated with 10 ml dichloromethane and 0.50 g of charcoal and stirred for 30 min, filtered and evaporated to dryness. N-propionyl-RCM-ester Ic was isolated as an off-white foam (5.96 g). HPLC analysis showed Ic (80.4 area %), Hc (2.4 area%) and dimers (4.8 area%, identified by HPLC/MS). The content by HPLC with internal standard was 74.5%, which corresponds to 89% yield. The crude product could be purified, if desired, by column chromatography on silica gel, eluent heptane/ethyl acetate. MS: [MH]+ 713.3.
HPLC method for content determination: Gemini C6-Phenol column, 4.6 x 150 mm, 3.0 um, solvent A: water/acetonitrile 95/5, solvent B: buffer Bu4N+HSO4 " pH 3 (Ig in 1 1 water/acetonitrile 9:1); solvent C: acetonitrile gradient from A/B/C 25/5/70 to 15/5/80 within 1.0 min, then 4 min isocratic, 500C, 210 nm, 2.3 ml/min. Retention times: N-propionyl-diene Hc 1.93 min, N-propionyl-RCM-ester Ic 2.07 min, int. standard dinitrobenzene (1 g/1 acetonitrile) 1.03 min.
Example 10 (S/C 20)
In a glove-box (O2 < 2 ppm) a solution of 60.0 mg (0.073 mmol, corrected by content) of N- benzoyl-diene Hd and 2.40 mg (0.0038 mmol) of catalyst 5024 in 1.7 ml of toluene (washed with aqueous hydrochloric acid and distilled under argon) was stirred at 600C in a 15 ml screw- capped flask. After 1.5 h two drops of ethyl vinylether were added and the mixture was stirred for ca. 30 min outside of the glove box. After addition of 1 ml of 1 M aqueous solution of hydrochloric acid the biphasic mixture was stirred for ca. 5 min. A 0.5 ml aliquote of the organic phase was removed and evaporated to dryness; the oily residue was dissolved in 1 ml of acetonitrile and analyzed by HPLC. Conversion was 99 area%, the desired product (N-benzoyl- RCM-ester Id) had 83 area % purity.
HPLC method for the determination of conversion and selectivity: Gemini C6 Phenyl (by Phenomena, Torrance Ca, USA), 4.6 x 150 mm, solvent A: water/acetonitrile 95/5, solvent B: acetonitrile, solvent C: buffer Bu4N+ HSO4 " pH 3 (1 g in 1 1 water/ acetonitrile 9:1), gradient from A/B/C 45/50/5 to 10/85/5 within 7.0 min, then 5 min isocratic, 500C, 210 nm, 2 ml/min. Retention times: toluene 2.5 min, diene-benzoate Hd 6.62 min, N-benzoyl-RCM-ester Id 5.96 min (identified by HPLC/MS, [M-H]+ 761.2 u), peaks of dimeric by-products at 6.5 to 9.1 min (HPLC-MS: [M-H]+ 1520 and 1576 u). Only the sum of the dimer peaks is given in the tables and experiments.
MS: [MHJ+ 761.2 u
NMR: (δ, CDClS, selected peaks): 1.25 (t. 3H), 1.34 (d, 9H)
Example 11
The examples in Table 4 were carried out using the same procedure and conditions as in Example 10, but in the presence of various catalysts.
Table 4
Example 12 (S/C 135) To a solution of 3.29 g (4.00 mmol) of N-benzoyl-diene Hd (96% purity) in 44 ml of toluene was added under argon bubbling (33 ml/min) at 600C 21.3 mg (0.03 mmol) of catalyst 5065. After 4.5 h stirring at this temperature 97 μl of ethyl vinylether were added followed by 67 μl (1.0 mmol) of ethylenediamine and the mixture was stirred at room temperature for 10 min. After this time the mixture was extracted with 1 M aqueous solution of hydrochloric acid and with water. The organic phase was treated with decolorizing charcoal, filtered and evaporated to dryness to afford 3.2 g of N-benzoyl-RCM-ester Id as a light brown solid. Crystallization of the crude product from ethanol afforded the desired Id (2.46 g, 81%) as an off-white crystalline solid with 93% purity.
Example 13 (S/C 135)
The examples in Table 5 were carried out using the same procedure and conditions as in Example 12, but in the presence of various catalysts.
Table 5
Example 14 (S/C 2000, cone. = 8%)
To a solution of 6.57 g (8.00 mmol) of N-benzoyl- diene Hd in 93 ml of toluene was added at 700C under vacuum (pressure = ca. 0.26 bar) by dropping funnel a solution of 2.78 mg (0.0039 mmol) of catalyst 5065 in 10 ml of toluene. The catalyst was added during 1 h. Under these conditions a small amount of toluene (ca 10 ml) distilled off in the course of the reaction. After 1.5 h of total reaction time 20 μl (0.20 mmol) of ethyl vinylether were added at ambient pressure followed after 1 h by 14 μl (0.20 mmol) of ethylenediamine and the reaction mixture was concentrated under vacuum. After addition of 10 ml of dichloro methane the solution was washed with 0.5 M aqueous solution of hydrochloric acid, treated with 5 ml of dichloromethane and evaporated to dryness. N-benzoyl-RCM-ester Id was isolated as a light tan solid (7.05 g). HPLC analysis showed 84.3 area% Id, 1.42 area% Hd and 10.3 area% dimers. The content by HPLC with internal standard was 70.3%, which corresponds to 81.5% yield.
Example 15 (Saponification of Id)
A suspension of 6.52 g (6.75 mmol) N-benzoyl-RCM-ester Id in 25 mL of THF, 25 mL of ethanol and 5 mL of water was cooled to 00C. At an internal temperature of 0.70C to 4.00C a solution of 4.0 g (98.01 mmol) sodium hydroxide in 20 mL of water was added within 22 min. The mixture was stirred for 16.5 h at 00C. At this temperature 12.9 mL (98.96 mmol) aqueous HCl 25% was added. The mixture was concentrated at 45°C/45 mbar to a residual weight of ca. 30 g. To the suspension 5 mL of water was added and extracted with 30 mL of dichloromethane. The organic layer was washed with 25 mL of water and the combined aqueous layers were extracted with 25 mL of dichloromethane. The combined organic layers there concentrated to a residual volume of 15 mL at 60°C/900 mbar. To the concentrate 50 mL of THF is added slowly and again concentrated to a residual weight of ca. 40 g at 60°C/700 mbar). Seeds were added and the suspension was stirred 1 h at room temperature and 1.5 h at 00C to complete the
crystallization. The crystals were collected on a filter nutsche and washed with 12 mL of THF (precooled to -200C). The crystals were dried for 5 h at 500C/ 10 mbar. 3.55 g of XXb with a purity of 97.2 % (yield 81.3 %) were obtained.
Example 16
XXb
To a solution of the N-acetyl-RCM-ester Ib (2.41 g, 2.88 mmol, 83.5% content) in 20 ml of ethanol was added under argon at ca. 30C (ice bath) a solution of sodium hydroxide (1.50 g, 36.7 mmol) in water (6.5 ml). The solution was stirred at 5-10 0C for 6 h, and then treated with 37%HC1 (4.5 ml) at ca. 3°C. The resulting suspension was concentrated and extracted with a mixture of dichloromethane (15 ml) and water (8 ml). The organic phase was evaporated, the oily residue was taken up in THF (25 ml). The resulting suspension was concentrated to a total weight of 12.6 g, stirred for 1 h at 55°C and in an ice bath for 3 h. The precipitate was filtered off, washed with cold THF and dried to constant weight (40°C/5 mbar/3 h) to afford 1.64 g of carboxylic acid XXb as a white solid with 97 area% according to HPLC and 89.2% content. Total content of dimers: 0.9%.
MS: [MH]+ 627.3
IR: carbonyl absorption at 1706 cm"1 (strong, broad) and 1680 cm"1 (medium, sharp).
Example 17 (telescoped process for the preparation of XXb)
A suspension of 90.2 g (191 mmol) (S)-2-tert-butoxycarbonylamino-non-8-enoic acid dicyclohexylammonium salt (commercially available from Synthetech Oregon, USA) in 373 g of THF was cooled to -50C and 22.7 g (188 mmol) pivaloylchloride was added within 30 min. The mixture was stirred for 1.5 h at 00C. At 5-100C 75.0 g (174 mmol) 4-fluoro-l,3-dihydro- isoindole-2-carboxylic acid (3R,5S)-5-((lR,2S)-l-ethoxycarbonyl-2-vinyl- cyclopropylcarbamoyl)-pyrrolidin-3-yl ester (XIV) was added in five portions followed by 18 g
THF. The suspension was heated to 20-250C and stirred for 4 h. After complete conversion 225 g of water was added and the solvent was removed at 500C under reduced pressure. To the residue 649 g of toluene was added and the internal temperature was decreased to 20-250C. To the suspension 80 g water and 8.57 g (87 mmol) 37% aqueous hydrochloric acid was added. The precipitated dicyclohexylammonium hydrochloride was removed by filtration and the filter cake was washed with 114 g toluene. To the filtrate 26 g toluene was added and phases were separated. The organic phase was treated at 20-250C with a mixture of 267g water, 43.0 g (301 mmol) 28% aqueous sodium hydroxide and 2.11 g (35 mmol) ethylene diamine for 30 min. Then phases were separated and the organic layer was washed with a mixture of 267 g water and 21.5 g (151 mmol) 28% aqueous sodium hydroxide. The organic phase was concentrated at 65°C under reduced pressure to a residual volume of 500 mL. The solution was cooled to -3°C and 27.5 g (196 mmol) benzoyl chloride was added. Then 84.6 mL (188 mmol) lithium tert-butoxide in THF was dosed within 1 h. After additional stirring for 15 min a sample showed conversions typically to be < 3% of diene XV. The mixture was heated to 20-250C and diluted with 337 g toluene. The solution was first washed with a mixture of 210 g water and 33.5 g (235 mmol)
28% aqueous sodium hydroxide, then with a mixture of 210 g water and 16.8 g (118 mmol) 28% aqueous sodium hydroxide and finally with a mixture of 210 g water and 11.6 g (117 mmol) 37% aqueous hydrochloric acid. The organic phase was then dried by concentrating to a residual volume of 650 mL at 65°C under reduced pressure. To the residue 865 g toluene were added and the solution was heated to 75°C jacket temperature. The pressure was reduced to 290-330 mbar and 167 mg (0.235 mmol) of catalyst 5065 dissolved in 35 g toluene and 13 g dichloromethane was added within 30 min. After stirring for additional 15 min a sample showed conversions typically to be < 3% N-benzoyl-diene Hd. Then 0.5 g water was added and the mixture was stirred for 10 min. The mixture was concentrated to a residual volume of 200 mL at 75°C and reduced pressure, 415 g THF and 496 g ethanol were added. The internal temperature was decreased to 20-250C and 106 g water was added. The suspension was cooled to 0-50C and 340 g (2.38 mol) 28% aqueous sodium hydroxide was added. The internal temperature was raised to 7-100C and the reaction mixture was stirred for 9-11 h. After this time the conversion was typically < 1% N-benzoyl-RCM-ester Id. At an internal temperature of 5-100C 237 g (2.40 mol) 37% aqueous hydrochloric acid was added. The internal temperature was raised to 400C and the suspension was concentrated to 700 mL under reduced pressure. At an internal temperature of 30-350C 108 g water and 620 g dichloromethane was added. The phases were separated and the aqueous phase was extracted with 124 g dichloromethane. The combined organic phases were washed with 94 g water and the aqueous phase was back-extracted with 102 g dichloromethane. The combined organic phases were concentrated to a residual volume of 300 mL at a jacket temperature of 800C. To the residue 899 g THF were dosed, first an amount what gave a reactor volume of 470 mL and after adding seeds, in such a rate the residual volume of 470 mL could be maintained during continued distillation. After all THF had been added the internal temperature
was decreased to 0-30C within 1.5 h. The crystals were collected on a filter nutsche and washed with 115 g THF. The product was dried for 3-6 h at 300C/ 15 mbar. 79.2 g of colorless crystals of XXb were obtained in an assay of 89 %wt which corresponds to a yield of 64%.
Example 18
Azlactone
XXb
K2CO3, o
°=S
H9N '^7
NaOMe, AcOEt/H2O
VlIl XXIb
Preparation of sodium ((2R,6S, 13aS, 14aR, 16aS,Z)-6-(tert-butoxycarbonylamino)-2-(4- fluoroisoiindoline-2-carbonyloxy)-5,16-dioxo-l,2,3,5,6,7,8,9,10,l l,13a,15,16a-hexade- cahydrocyclopropa[e]pyrrolo [ 1 ,2-a] [ 1 ,4]diazacyclopentadecine- 14a-carbonyl) (cyclo- propylsulfonyl)amide (HCV protease inhibitor; compound XXIIb).
To a suspension of 30.0 g (0.043 mol) of carboxylic acid (product of example 11 with an assay of 90.2%(m/m)) and 14.0 g of sodium carbonate in 225 g of tetrahydrofuran was added at 45°C within 30 minutes 7.60 g (0.074 mol) of acetic acid anhydride and the resulting mixture was stirred at 45°C for 8 hours. To the resulting suspension was then added 30.2 g (0.17mol) of potassium carbonate and 8.0 g (0.065 mol) of cyclopropyl sulfonamide. The mixture was heated to 620C and stirred at this temperature for 17 hours. The mixture was concentrated to a residual volume of 200 ml and then treated with 200 g of water. The biphasic mixture was stirred for 15 minutes and the layers were then allowed to separate. The lower aqueous phase was removed.
The organic phase was diluted with 90 g of ethyl acetate and washed with 3% sulfuric acid (1x140 g) and water (3x130 g). The organic layer was concentrated to dryness and then diluted with 400 ml of ethyl acetate. Residual amounts of water were removed by a continuous azeotropic distillation with ethyl acetate. The mixture was then treated at 100C with 20 ml of methanol, followed by 10.0 g of sodium methylate (30% in methanol). From the resulting mixture approx. 300 ml of ethyl acetate/methanol were then distilled off. The mixture was then treated at 34°C within one hour with 300 ml of ethyl acetate and 5 g of water. The resulting mixture was allowed to cool to ambient temperature within 4 hours. The crystals were filtered off, washed with 80 ml of ethyl acetate and dried at 80°C/<30 mbar for 20 hours to afford 30.4 g (87% corrected yield) of the title compound as white crystals with an assay of 92.7 %(m/m). MS: 732.28 (M++ H), 676.23, 632.25.
1H-NMR (400MHz, DMSO-d6): 7.89-7.80 (m, IH), 7.39-7.31 (m, IH), 7.21-7.06 (m, 2H), 6.97- 6.90 (m, IH), 5.49-4.41 (m, IH), 5.31-5.21 (m, 2H), 4.66 (s, br, 4H), 4.45-4.35 (m, IH), 4.19- 4.08(m, 2H), 3.91-3.81 (m, IH), 2.68-2.58(m, IH), 2.30-2.14 (m, 3H), 2.0-1.2 (m, 12H), 1.17 and 1.14 (2s, 9H), 0.78-0.69 (m, 2H), 0.62-0.53 (m, 2H).