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US 2004/0175808 A1Published application
Process to ribofuranose sugar derivatives as intermediates to branched-chain nucleosides
AssigneeMerck & Co., Inc.
InventorsKimberly A. Savary, Zhiguo J. Song, J. Michael Williams, Feng Xu
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Abstract
A novel process is provided for the preparation of ribofuranose sugar derivatives which are useful in the synthesis of branched-chain ribonucleoside inhibitors of HCV polymerase for the treatment of HCV infection. Also provided are useful intermediates obtained from the instant process.
Claims16
A process for preparing a compound of structural formula I:
- 11
- wherein R1 is C2-4 alkenyl, C2-4 alkynyl, or C1-6 alkyl unsubstituted or substituted with one to three substituents independently selected from fluorine, hydroxy, amino, mercapto, C1-3 alkoxy, and C1-3 alkylthio;
- and
- R2 is C1-6 alkyl or aryl unsubstituted or substituted with one to three substituents independently selected from methoxy, methyl, and fluorine;
- comprising the step of cleaving the R3 protecting group in a compound of structural formula V:
- 12
- wherein R3 represents benzyl unsubstituted or substituted with one to three substituents independently selected from methyl, methoxy, halogen, and nitro.
4 more elements
A compound of structural formula VI:
- 19
- wherein R2 is hydrogen, methoxy, methyl, or fluorine.
A process for preparing a compound of structural formula I:
- 21
- comprising the steps of:
- (a) producing a compound of structural formula II:
- 22
- wherein R3 represents benzyl unsubstituted or substituted with one to three substituents independently selected from methyl, methoxy, halogen, and nitro;
- by treating a compound of structural formula III:
- 23
- with aqueous acid in an organic solvent;
- (b) producing a compound of structural formula IV:
- 24
- wherein R4 is hydrogen or formyl;
- by oxidative cleavage of the compound of structural formula II;
- (c) producing a compound of structural formula V:
- 25
- by treating a compound of structural formula IV with base in an organic solvent;
- and
- (d) cleaving the R3 protecting group in a compound of structural formula V.
14 more elements
Dependencies are inferred from the claim text.