Ethylene Glycol → 5-Benzyloxy-2,2-dimethyl-7-(1,1-dimethylheptyl)-3,4-dihydro-2H-benzopyran-4-carboxylic acid

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Reaction Steps

A mixture of 2.0 g 5-benzyloxy-4-cyano-2,2-dimethyl-7-(1,1-dimethylheptyl)-3,4-dihydro-2H-benzopyran, 20 g potassium hydroxide and 100 ml ethylene glycol are heated under nitrogen at reflux for 18 hours and cooled to ambient temperature. The mixture is acidified to pH 3 with concentrated hydrochloride acid, extracted with ethyl acetate and the extracts dried (MgSO4). Evaporation of solvent gives an oil which is taken up in ethyl ether, washed with water, brine, dried (MgSO4) and the solvent evaporated to give 2.09 g of crude solid. The crude was purified by chromatography on silica gel, eluting with ethyl ether/hexane. The combined product fractions are combined and solvent evaporated to afford 1.69 g of product, m.p. 137°-138° C.

Provenance & Evidence