Diethyl Oxalate → 8-methyl-4-oxo-7-(phenylmethoxy)-4H-1-benzopyran-2-carboxylic acid

Participants

Reaction Steps

A mixture of 1-[2-hydroxy-3-methyl-4-(phenylmethoxy)phenyl]-ethanone (0.098 mol) and ethanedioic acid, diethyl ester (0.11 mol) in toluene (100 ml) was added dropwise to a mixture of sodium methoxide (0.22 mol) in toluene (150 ml). The reaction mixture was stirred and refluxed for 2 hours. The solvent was evaporated. The residue was added to a mixture of acetic acid (150 ml) and hydrochloric acid (50 ml). The reaction mixture was stirred and refluxed for 1 hour. The mixture was poured out onto ice. The resulting precipitate was filtered off and dried (vacuum; 70° C.), yielding 29 g (95.4%) of 8-methyl-4-oxo-7-(phenylmethoxy)-4H-1-benzopyran-2-carboxylic acid (interm. 9).

Provenance & Evidence