- A process for the manufacture of famciclovir using phase-transfer catalysts
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The invention relates to a process for the preparation of Famciclovir, which comprises the preparation of a compound of formula (II) wherein X is a halogen atom by reaction of a compound of formula (III) with a compound of formula (VII) wherein L is a leaving group, in the presence of a catalytic amount of a quaternary ammonium salt, followed by hydrogenation of compound (II) to Famciclovir.
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Page/Page column 5
(2008/06/13)
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- Convenient syntheses of 9-[4-hydroxy-3-(hydroxymethyl)butyl]guanine (penciclovir) and 9-[4-acetoxy-3-(acetoxymethyl)butyl]-2-amino-9h-purine (famciclovir)
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Guanine 11 was converted, in a one pot reaction, into 2-amino-6-[(4- chlorophenyl)sulfanyl]purine 9a in 88% isolated yield. 4-Acetoxy-3- (acetoxymethyl)butanol 123 was prepared from 2-chloroethanol in five steps and in 46% overall yield. The mesylate ester of compound 23 reacted with 9a in the presence of potassium carbonate with a high degree of regioselectivity (89%) to give the N-9 alkylated product 26 which was isolated in 80% yield. Acidic hydrolysis of the latter compound 26 gave penciclovir 4 in virtually quantitative yield. Penciclovir 4 and famciclovir 5 were prepared from 2- amino-6-[(4-chlorophenyl)sulfanyl]purine 9a in four and five steps, respectively, by procedures involving initial alkylation with 1,2- dibromoethane. The overall yields obtained were 65 and ca. 60%, respectively.
- Brand, Briony,Reese, Colin B.,Song, Quanlai,Visintin, Cristina
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p. 5239 - 5252
(2007/10/03)
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