p-Toluenesulfonic acid → Balaglitazone

Participants

Reaction Conditions

Reaction Steps

A suspension of 5-[4-[(carboethoxy)methoxy]benzyl]thiazolidine-2,4-dione obtained by following a procedure described in any of Examples 16-22 (100 g, 0.32 M), N-methyl anthranilamide (58.7 g, 0.39 M) and p-toluenesulfonic acid (˜200 mg) was taken in a round bottom flask fitted with a mechanical stirrer, oil bath and Dean-Stark condenser. The reaction mixture was heated to reflux (Internal temperature 150-155° C., oil bath temperature 170-180° C.) for a period of 45-55 h while monitoring the reaction by TLC. After completion of the reaction, the reaction mass was cooled to 80° C. and methanol (700 ml) was added slowly through a dropping funnel. The reaction mass was allowed to attain room temperature while stirring and the solid thus obtained was filtered and washed with methanol (150 ml) and dried at 100-120° C. for 1 h to afford 5-[4-[[3-methyl-4-oxo-3,4-dihydroquinazolin-2-yl]methoxy]benzyl]thiazolidine-2,4-dione as a white solid (68 g, Y=53%, P=98%).

Provenance & Evidence