合成路线1

The starting 6α,9α-difluoro-11β,17α-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxylic acid (I) is converted to the analogous carbothioic acid (II) via activation with carbonyl diimidazole, followed by reaction with hydrogen sulfide gas (1). The α-hydroxyl group of (II) is then selectively acylated with 2-furoyl chloride (III) to give the 17-furoate ester (IV) (2, 3). Finally, condensation of thioacid (IV) with bromofluoromethane under basic conditions provides the target fluoromethyl thioester (2-4).