Hydrogen Bromide → 6-Chloro-7-hydroxy-3,4-dihydrocarbostyril

Participants

Reaction Steps

The thus-obtained 30 g of 6-chloro-7-methoxy-3,4-dihydrocarbostyril are dispersed in 300 ml of 47%-hydrobromic acid aqueous solution and heated for 4 hours under refluxing condition. After cooling of the reaction mixture, the insoluble matter is separated by filtration, washed with water and dried. Recrystallization from methanol-chloroform obtains 25 g of 6-chloro-7-hydroxy-3,4-dihydrocarbostyril in the form of colorless needle-like crystals with a melting point of 264°-266° C.

Provenance & Evidence