Isopropenyl acetate → 1,17-Diacetoxy-3-methoxyestra-1,3,5(10),16-tetraene

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Reaction Steps

A solution of 1-acetoxy-3-methoxyestra-1,3,5(10)-trien-17-one (8.84 g, 26 mM), isopropenyl acetate (132 g, 1320 mM) and p-toluenesulfonic acid monohydrate (1.34 g, 7 mM) is heated at 120° in a distilling flask equipped with a 5 inch Vigreaux column to insure slow distillation. After heating at 120° for 16 hrs, 5 ml of distillate is collected. The temperature is increased to 140° and after 45 mins an additional 60 ml of isopropenyl acetate is collected. The residue is poured into 750 ml of ether and the ether solution is extracted with saturated NaHCO3 solution and H2O. The ether extract is dried over MgSO4 and evaporated in vacuo to give a residue containing the enol acetate and recovered starting material as the major components. The residue is chromatographed on 300 g of neutral silica gel and the column is eluted with 0.5% acetone:petroleum ether to give 1,17-diacetoxy-3 -methoxyestra-1,3,5(10),16-tetraene, yield 6.1 g (61%); m.p. 118° (petroleum ether).

Provenance & Evidence