Synthesis of steroidal extranucleo 1,3,4-oxadiazoles

Cholest-5en-3 beta-ol 1,3,3-ethylenedioxy-androst-4-en-17 beta-ol 2 and 17,17-ethylenedioxy-1,3,5(10)-estratrien-3 beta-ol 3 were converted into ethyl ester 1a, 2a and 3a by reaction with ethyl chloroacetate in the presence of potassium. The ethyl esters 1a, 2a and 3a on reaction with hydrazine gave hydrazides 1b, 2b and 3b, which on reaction with cyanogen bromide afforded 1,3,4-oxadiazoles 1c, 2c and 3c.