Hydrochloric Acid → 1-Chloro-4-hydroxyisoquinoline-3-carboxylic acid

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Reaction Steps

A mixture of 9.23 g of 1-chloro-4-hydroxy-isoquinoline-3-carboxylic acid butyl ester (33 mmol), 90 ml of 2.5N aqueous sodium hydroxide solution, water (20 ml) and ethanol (110 ml) was refluxed with stirring for 2 h. Then the pH of the mixture was adjusted to 2 by the addition of concentrated aqueous hydrochloric acid. During the addition, the temperature of the mixture was kept at 20° C. by cooling with an ice bath. Stirring was then continued for 1 h before the solid component was separated by vacuum filtration. The filter cake was washed with water and dried in vacuo at 85° C. to give a white powder. 6.64 g of the title compound were obtained; MS-(+)-ion: M+1=224.1 amu.

Provenance & Evidence