Methanol → Androsta-4,16-dien-3-one

Participants

Reaction Steps

This synthesis is depicted in FIG. 1. Several methods are known for the conversion of testosterone into Androsta-4,16-dien-3-one (Brooksbank et al., Biochem. J. (1950) AZ:36). Alternatively, thermolysis (460°) of the methyl carbonate of testosterone gives Androsta-4,16-dien-3-one in 90% yield. 17B-MethoxyCarbonyioxy-androst-4-en-3-one (IV) was prepared from testosterone (III. Fluka) with methyl chloroformate/pyridine (a) in 76% yield (after recrystallization from MeOH). M.p. 140-°141°, [a]D =+95.4° (c=1.10) - IR. (CDCl3): 1740s, 1665s, 1450s, 1280s, - 1H-NMR. (360 MHz): 0.87 (s, 3 H); 1.20 (s, 3H); 3.77 (s, 3H); 4.53 (br. t, J 8, 1H); 5.75 (s, 1H). A solution of the methyl carbonate IV in toluene was pyrolyzed (b) as described for I. Recrystallization of the crude product from acetone at RT. gave pure ketone 4 in 90% yield. M.p. 127°-129.5°, (a)D +118.9° (C=1.32) ([3]: m.p. 131.5°-133.5° (hexane), [a]D16 =+123°±3.5° (C=1.03)). - IR. (CDCl3): 3050w, 1660s, 1615m. - 1H-NMR. (360 MHz): 0.82 (s, 3H); 1.22 (s, 3H); 5.70 (m, 1H); 5.73 (s, 1H); 5.84 (m, 1H).

Provenance & Evidence