Hydrochloric Acid → 9-bromo-6-carbamoyl-5H-pyrido[4,3-b]indole-3-carboxylic acid

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Reaction Conditions

Reaction Steps

A suspension of crude ethyl 9-bromo-6-cyano-5H-pyrido[4,3-b]indole-3-carboxylate (0.78 g, 2.266 mmol) and sodium perborate tetrahydrate (1.395 g, 9.07 mmol) in ethanol-water (3:2, 99 mL) was heated at 100° C. for 3 h. The mixture was cooled to room temperature and the ethanol was removed under vacuum to give a suspension. The pH was adjusted to about 5-6 with 1 M aqueous HCl. The precipitate was collected by filtration, washed with water and air-dried to afford the desired product (0.60 g). The filtrate was concentrated under vacuum to provide additional desired product (70 mg, total of 88% yield). LCMS (M+H)+ m/z 334.0, 335.9.

Provenance & Evidence