Department of Chemistry, Nizam College, Hyderabad-500 001 Manuscript received 13 May 1988, accepted 23 August 1988 17-Oxo-5-androsten-3\(\beta\)-yl acetate (1a) and 3\(\beta\) -chloro-17-oxo-5-androstene (2a) on reaction with hydrazine hydrate in alcoholic solution gave 5-androsten-17-hydrazone­-3\(\beta\) -yl acetate (1b) and 3\(\beta\) -chloro-5-androsten-17-hydrazone (2b), respectively. The subsequent reaction of these 17-hydrazones (1b, 2b) with phenyl isocyanate in benzene solution afforded the corresponding 17-N-pbenylsemlcarbazone derivatives (1c, 2c), whose cyclisation with chloroacetic acid in the presence of anhydrous sodium acetate and acetic acid yielded 20,21-diazo-S-androsten-21-(N-phenyl-1',3'-ozszolin-4'-one)- 3\(\beta\) -yl acetate (3a) and 3\(\beta\) -chloro-20,21-diazo-5-androsten-21-(N-phenyl-1',3' f-oxazolin­4'-one) (4a), respectively.