As a kind of substrate competition type 5α reductase inhibitor,finasteride is a promising medicine used in the clinical treatment of benign prostatic hyperplasia (BPH).In this paper,a new route for the synthesis of finasteride from pregnenolone was proposed.Thus,pregnenolone was converted to finasteride in 10 steps,i.e.,ammoniumation,methoxylation,Oppenauer oxidation,hydrolyzation,cleavage of Δ 4 double bond by oxidation,ring closure by ammonia,hydrogenation of Δ 5 double bond,esterification with methanol,dehydrogenation of 1,2 position in A ring and Bodroux reaction.In this route,expensive reagent 2,2 dipyridyl disulfide commonly used in previous literature was avoided.All of the desired compounds were characterized by MS or/and NMR.The overall yield of finasteride was 13.67% based on pregnenolone.
