- Convenient synthesis of s-fluoromethyl 6alpha, 9alpha-difluoro-11beta-hydroxy-16alpha-methyl-17alpha-propionyloxy-3-oxoandrosta-1,4-diene-17beta-carbothioate
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The present invention provides a convenient process for the preparation of S-fluoromethyl 6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-propionyloxy-3-oxoandrosta-1,4-diene-17β-carbothioate, a compound of formula 1, comprising (a) treating 17β-[(N,N-dimethylcarbamoyl)thio]carbonyl-6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-propionyloxy-3-oxoandrosta-1,4-diene, a compound of formula 3 with alkali metal carbonate-alcohol system to obtain 6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-propionyloxy-3-oxoandrosta-1,4-diene-17β-carbothioic acid, a compound of formula 4; (b) reacting the compound of formula 4 with bromofluoromethane to yield the compound of formula 1. The present invention also provides an improved process for preparation of compound of formula 1 comprising (a) reacting 6α,9α-difluoro-11β-hydroxy-16α-methyl-3-oxo-17-(propionyloxy)androsta-1,4-dien-17β-carboxylic acid, a compound of formula 2, with N,N-dimethylthiocarbamoyl chloride in an inert aprotic solvent in the presence of an iodide catalyst and a base to give a compound of formula 3, (b) reacting the compound of formula 3 with a hydrosulfide reagent and bromofluromethane to obtain a compound of formula 1.
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Page/Page column 10-11
(2010/02/14)
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