Water → 17beta-Carboxy-6-t-butoxycarbonyl-6-azaandrost-4-en-3-one

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Reaction Steps

A solution of 17β-carbomethoxy-6-t-butoxycarbonyl-6-azaandrost-4-en-3-one (15.4 g, 36 mmol), from part E, in dioxane (150 mL) and water (100 mL) is treated with LiOH.H2O (3.31 g, 79 mmol) and stirred overnight in a water bath. The reaction is poured into saturated aqueous NaHSO4 (150 mL), extracted with methylene chloride (3×100 mL), extracts washed with saturated aqueous NaCl, dried over MgSO4 and concentrated to a volume of 100 mL. At this point crystals begin to form and 2:1 hexanes/ethyl acetate (50 mL) is added, the mixture triturated, cooled to room temperature and 17β-carboxy-6-t-butoxycarbonyl-6-azaandrost-4-en-3-one collected as a fluffy white powder; yield: 9.44 g (63%); m.p. 215°-216° C. Anal. Calcd. for C24H35NO5.1/4H2O; C, 68.30; H, 8.48; N, 3.32. Found: C, 68.45; H, 8.41; N, 3.28.

Provenance & Evidence