Sodium Hydroxide → DR 3438

Participants

Reaction Steps

In 1.2 l of ethanol was suspended 132 g of ethyl {[5-chloro-3-(2-methylphenyl)-4-oxo-4H-1-benzopyran-7-yl]oxy}acetate, and 0.53 l of a 1N sodium hydroxide aqueous solution was slowly added dropwise to the suspension at room temperature, followed by stirring at room temperature for 3 hours. The insoluble material was removed by filtration, and the filtrate was acidified with hydrochloric acid while ice-cooling and stirring. The stirring was continued at room temperature overnight. The precipitated crystals were collected by filtration, washed with water, and dried to obtain 105 g of the entitled compound having a melting point of 191° to 192° C.

Provenance & Evidence