Intermediate for synthesizing new 7beta-substituted-4-aza-5alpha-cholestanone being 5alpha-reductase inhibitor

PURPOSE: To provide a new compd. useful for preventing and treating a 5α-reductase inhibitor, benign prostatic hypertrophy, acne, female hirsutism, male alopecia, androgenic hormone alopecia, prostatism and prostatic cancer. CONSTITUTION: A compd. represented by formula I (wherein Z is α-H or a β-substituent selected from alkyl and carboxyalkyl), for example, 7-methyl-5-oxo- A-nor-3,5-secocholestanic acid is designated and synthesized from a compd. represented by formula II through a compd. represented by formula III. COPYRIGHT: (C)1995,JPO