Hydrochloric Acid → 8-Ethoxycarbonylamino-5-hydroxy-3,4-dihydrocarbostyril

Participants

Reaction Steps

10.7 g of 8-amino-5-hydroxy-3,4-dihydrocarbostyril hydrochloride was dissolved in 200 ml of a 10% aqueous sodium hydroxide solution, 5.4 g of ethyl chlorocarbonate was added to the solution while stirring at room temperature followed by stirring for one hour at 30° C. After completion of the reaction, the reaction mixture was rendered acidic with hydrochloric acid under ice-cooling, the precipitated crystals were recovered by filtration, washed with water and dried. Recrystallization of the dried crystals from ethanol yielded 7.95 g of 8-ethoxycarbonylamino-5-hydroxy-3,4-dihydrocarbostyril as colorless needle crystals having a melting point of 283.8°-284.6° C.

Provenance & Evidence