Sodium borohydride → 5 Alpha-androst-16-en-3 beta-ol

関与物質

反応手順

This synthesis is depicted in FIG. 1. Ketone 1 (500 mg, 1.84 mmol) Was reduced with sodium borohydride (d, 75 mg, 2 mmol) in THF/MeOH 5:1 (18 ml) at RT (2 h). The crude product was chromatographed on silica gel (60 g) using toluene/ethyl acetate 2:1. After traces of the axial alcohol 2 (9 mg, 2%) were observed, the pure equatorial alcohol 3 (388 mg, 77%) was eluted. An analytical sample was recrystallized from MeOH/water. M.p. 124°-125°, [a]D =+14.2° (c=1.12) ([2]: m.p. 125°-127°, [a]D17 =+11.2° (c=0.76)). --IR. (CDCl3): 3620m, 3430w, 1590w. --1H-NMR. (360 Mhz): 0.77 (s, 3 H); 0.85 (s, 3 H); 3.60 t×t, J=11 and 5, 1 H); 5.70 (m, 1 H); 5.84 (m, 1 H).

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