Hydrochloric Acid → HCID 21463032, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-methyl-2-oxo-4-phenyl-2H-1-benzopyran-3-carboxylic acid ethyl ester [prepared by heating 2-hydroxy-5-methylbenzophenone and diethyl malonate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-en; melting point: 129°-131° C.; NMR (200 MHz, CDCl3) ppm: 0.96 (3H, t, J=7.2 Hz), 2.31 (3H, s), 4.07 (2H, q, J=7.2 Hz), 7.01 (1H, bs), 7.2-7.4 (4H, m), 7.5-7.6 (3H, m)] (10.0 g), acetic acid (100 ml). and hydrochloric acid (60 ml) was heated under reflux at 110° C. for 15 hours. After the solvent was distilled off, ethyl acetate was added to the residue. The mixture was washed with water and dried, after which the solvent was distilled off, to yield 6-methyl-2-oxo-4-phenyl-2H-1-benzopyran-3-carboxylic acid as colorless crystals (8.7 g).

Provenance & Evidence