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

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Reaction Steps

A mixture of 5.0 g. of 5-benzyloxy-2,2-dimethyl-7-(1,1-dimethylheptyl)-3,4-dihydro-2H-benzopyran-4-carboxylic acid (prepared by the method of Example 88, Part A), 500 mg. 5% palladium-on-carbon catalyst and 150 ml. ethyl acetate is hydrogenated for 18 hours by the procedure of Example 86. After removal of catalyst and evaporation of solvent 4.25 g. of foam is obtained. Purification by silica gel chromatography, eluting with 2:1 hexane/ethyl ether affords 1.84 g. of product, M.P. 147°-148° C.

Provenance & Evidence