Phosphorus oxybromide → 1-Bromo-4-hydroxy-7-phenylsulfanyl-isoquinoline-3-carboxylic acid

Participants

Reaction Steps

1,4-Dihydroxy-7-phenylsulfanyl-isoquinoline-3-carboxylic acid butyl ester (Example A-63 d) Compound A) (29.0 g) and phosphorous oxybromide (67.5 g) in 600 ml anhydrous acetonitrile was stirred at reflux for 4 hours. After cooling the reaction mixture was concentrated and saturated sodium bicarbonate solution and ethyl acetate were added to the residue and stirred overnight. Precipitate that formed between layers was collected and washed with water to give the title compound (10.2 g). MS-(+)-ion M+1=376.0, 378.1.

Provenance & Evidence