Acetic Anhydride → 3-hydroxy-3-cyano-3,4-dihydro-2H-1,5-benzodioxepin

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Reaction Steps

A solution of 13.5 g. (208 millimoles) of potassium cyanide in 27 ml. of water is added dropwise to a mixture of 18.7 g. (114 millimoles) of 3-oxo-3,4-dihydro-2H-1,5-benzodioxepin and 21.2 g. (208 millimoles) of acetic anhydride with stirring and cooling. The mixture is stirred at ambient temperature overnight and then is made alkaline with 10% sodium carbonate solution. The product in the form of an oil is extracted with diethyl ether, treated with charcoal and dried over calcium sulfate. Evaporation of the solvent gives a solid that is recrystallized from carbon tetrachloride to give 3-hydroxy-3-cyano-3,4-dihydro-2H-1,5-benzodioxepin as plates, m.p. 108.5°-110° C.

Provenance & Evidence