Formic Acid → 5beta-Pregn-3-en-20-one

Participants

Reaction Steps

A mixture of 250 mg of progesterone, 7.5 g of zinc dust, 18.75 ml of methylene chloride and 6.25 ml of 90% formic acid was shaken at room temperature for 18 hours, whereupon it was worked up by the procedure described in Example 36. Concentration of a solution of the crude product in methylene chloride with intermittent addition of pentane gave 99.18 mg of 5β-pregn-3-en-20-one, mp 135°-136.5°, 139.5° C., nmr (CDCl3,δ) 5.5 (2, broadened dd; 3--H, 3--H, 4--H), 2.12 (3, S; 21--H) 0.96 (3, S; 19--H), 0.77 (trace, S; 19--H of 5α-isomer?) and 0.61 (3, S; 18--H) ppm.

Provenance & Evidence