Collect. Czech. Chem. Commun. 1980, 45, 3008-3022

Synthesis of 3,4-, 4,5- and 5,6-unsaturated 19-substituted cholestane derivatives and related epoxides

Pavel Kočovský

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


Starting from the 5,6-unsaturated compound X, 19-hydroxy-, 19-methoxy and 19-acetoxy derivatives with the double bond in positions 5,6- (XIV-XVI), 4,5- (XXI-XXIII) and 3,4- (XXX, XXXIII, XXXIV) were prepared by stepwise transposition of the 5,6-double bond. The route to 4,5-unsaturated steroids involves hypobromous acid addition (XVIXVIII) followed by reductive removal of bromine and dehydration (XIXXXI), Transposition of the 4,5-double bond to the 3,4-position is based on the conversion of the 4,5-olefin into 4β-alcohol (XXIIIXXVII) and pyrolysis of its benzoate (XXVIIIXXX).