Ethanol → Bromo-4-oxo-3,4-dihydro-phthalazine-6-carboxylic acid ethyl ester

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Reaction Steps

Concentrated sulfuric acid (40 ml) was added to a stirred solution of 1-bromo-4-oxo-3,4-dihydro-phthalazine-6-carboxylic acid (85 g, 0.32 mol) in EtOH (500 ml) and the mixture was heated to reflux for 48 hours. After this time, the reaction mixture was cooled and the resulting precipitate was filtered. The precipitate was partitioned between EtOAc (1 L) and saturated NaHCO3 (500 ml), the organic layer was separated and washed with water (500 ml) before being dried (MgSO4), filtered and concentrated under vacuum to give the title compound (30 g, 31% yield) as a white solid. Tr=1.23 min, m/z (ES+) (M+H)+ 297 & 299

Provenance & Evidence