Potassium Hydroxide → Dihydro-2H-pyran-4,4(3H)-dicarboxylic acid

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Reaction Steps

6M potassium hydroxide solution (10 mL, 60 mmol) was added to an ice-cooled solution of tetrahydropyran-4,4-dicarboxylic acid diethyl ester (5 g, 21.7 mmol) in ethanol (40 mL) and heated at reflux overnight. The volatiles were evaporated, the residue diluted with water and acidified with conc. hydrochloric acid. The mixture was allowed to stand overnight then extracted with ether (3×25 mL). The combined ether layers were washed with brine, dried over sodium sulfate, and concentrated in vacuo to afford tetrahydro-pyran-4,4-dicarboxylic acid (2.3 g, 61%) as a white solid.

Provenance & Evidence