Citric Acid → Estradiol sulfamate

Participants

Reaction Conditions

Reaction Steps

To a cold (2-5° C.) suspension of moist 17-Oxoestra-1,3,5(10)-trien-3-yl sulfamate (171.7 mmol, from procedure I) in ethanol (450 ml), a solution of sodium borohydride (156.23 mmol) in water (94 ml) was added at 2-5° C. within a period of 20 minutes. The resulting mixture was stirred at 2-5° C. for another 20 hours. A solution of citric acid (495.86 mmol) in water (668 ml) was then added at this temperature within a period of 15 minutes to adjust the pH to 3. Water (668 ml) was added. The resulting crystalline solid was filtered and washed three times with water (500 ml). The wet crystals were suspended in acetone (2010 ml) and the resulting suspension was heated under reflux until complete dissolution. Removal of acetone (1700 ml) by destination resulted in a suspension, which was cooled to ambient temperature and filtered. The crystalline solid was washed with cold acetone (50 ml) and dried in vacuum. Yield: 45.06 g white crystals, purity (HPLC): 99.61%.

Provenance & Evidence