Acetyl chloride → 7-bromo-3,4-dihydro-1H-2-benzopyran-1,3-dione

Participants

Reaction Steps

A oven-dried 10 mL round-bottomed flask containing a stirring bar was charged with 5-bromo-2-(carboxymethyl)benzoic acid (500 mg, 1.93 mmol). Freshly distilled acetyl chloride (5.0 ml) was added, the flask was fitted with a condenser and the reaction mixture was refluxed under an argon atmosphere for 16 h. The reaction was then cooled to room temperature and the excess acetyl chloride was removed in vacuo. The solid obtained was triturated with Et2O (5.0 mL), filtered and dried to give 7-bromoisochroman-1,3-dione as an off white solid (404.7 mg, 87%). Spectral data for this compound were consistent with those in the literature. M.p. 176-178° C. (lit.7 M.p. 171-173° C.); 1H NMR (400 MHz, DMSO-d6): δ=8.13 (s, 1H), 7.94 (d, J=8.2 Hz, 1H), 7.41 (d, J=8.2 Hz, 1H), 4.23 (s, 2H).

Provenance & Evidence