Acetic Acid → (3beta,5alpha)-3-(Acetyloxy)pregn-16-en-20-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 1 (50 g, 120.0 mmol), (CH3CO)2O (150 mL), and C5H5N (10 mL) was boiled for 1 h, cooled to 100° C., stirred, treated with TiCl4 (2.5 g, 13.16 mmol) in (CH3CO)2O (2.5 mL), boiled an additional 2 h, cooled to 40° C., treated gradually with CH3COONa (10 g) dissolved in water (25 mL), stirred 20 min, cooled to room temperature, poured into CH3COCH3 (220 mL) and CH3COOH (220 mL), oxidized by addition of CrO3 (15 g) in water (7.5 mL) at 15-18° C., stirred an additional hour, treated with isopropanol (7.5 mL), gradually heated to distill off acetone and reach a temperature of 115-117° C., boiled for 1.5 h, cooled to room temperature, and treated with water (425 mL). The resulting precipitate was filtered off, washed with water, and recrystallized from methanol:acetone (3:1) to afford 2 (29 g, 69.5%), mp 158-162° C., lit. mp 158-162° C. [2].

Provenance & Evidence