反应详情

A solution of sodium hydroxide (7.35g.) in water, (55 ml.) was stirred at -5° and bromine added slowly maintaining the temperature between -5° and 0°. Cold dioxan (45 ml.) was added and the pale yellow sodium hypobromite solution stirred at 0° until required. 3α-Hydroxy-16α-methyl-5α-pregnane-11, 20-dione (5.0g.) was dissolved in dioxan (200 ml.) and water (55 ml.). The hypobromite solution was added over 5 min. and the resulting mixture kept between 5° and 10° with stirring for 3 hr. Sodium sulphite heptahydrate (2.8g.) in water (15 ml.) was added and the solution refluxed for 15 min. The mixture was acidified and concentrated to incipient crystallisation before pouring into water (1 1.). Filtration afforded the title compound (3.85g.); m.p. 265°-268°.

1. temperaturemaintaining the temperature between -5° and 0°
2. customkept between 5° and 10°
3. temperaturethe solution refluxed for 15 min
4. concentrationconcentrated to incipient crystallisation
5. additionbefore pouring into water (1 1.)
6. filtrationFiltration