Collect. Czech. Chem. Commun. 1984, 49, 1051-1059

Synthesis of 4-(21-nor-5-pregnen-20-yl)-1,3-thiazole derivatives

Pavel Drašar, Vladimír Pouzar, Ivan Černý and Miroslav Havel

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The keto sulfoxide IV, prepared from the ester III, was reduced with amalgamated aluminium to give the ketone V which after enolization and silylation afforded the silyl enol ether VI. Oxidation of VI with osmium tetroxide and N-methylmorpholine N-oxide monohydrate yielded the α-hydroxy ketone VII. This was converted into the mesylate IX and further into the bromo ketone XI which on Hantzsch reaction with ethyl thioxamate furnished the steroidal thiazole XII. Compound XII was converted into the hemisuccinate XIV.