反应详情

3α-Hydroxy-5α-pregnane-11,20-dione (2 g) was dissolved in glacial acetic acid (50 ml). Paraformaldehyde (1.2 g), morpholine (2 ml) and conc. hydrochloric acid (2 ml) were added and the stirred mixture heated between 105°-110° C for 4 hours. The excess acetic acid was removed in vacuo and the red oil obtained partitioned between 0.1 N hydrochloric acid and ethyl acetate. The aqueous layer was basified with saturated sodium bicarbonate solution and the emulsion formed extracted into ethyl acetate. The organic layer was washed with water, dried (Na2SO4) and evaporated to a yellow foam which was purified by preparative t.l.c. (ethyl acetate) to give title compound (550 mg) as a foam [α]D + 100° (c, 0.11).

1. temperaturethe stirred mixture heated between 105°-110° C for 4 hours
2. customThe excess acetic acid was removed in vacuo
3. customthe red oil obtained
4. custompartitioned between 0.1 N hydrochloric acid and ethyl acetate
5. customthe emulsion formed
6. extractionextracted into ethyl acetate
7. washThe organic layer was washed with water
8. dry with materialdried (Na2SO4)
9. customevaporated to a yellow foam which
10. customwas purified by preparative t.l.c