Phthalic Anhydride → 2-(3-Bromophenyl)-1H-isoindole-1,3(2H)-dione

Participants

Reaction Steps

A stirring slurry of 3-bromoaniline (3.00 g, 17.44 mmol), phthalic anhydride (2.58 g, 17.44 mmol), and toluene (45 ml) was heated under reflux, using a Dean-Stark apparatus, at 140° C. (oil bath temperature) for 24 h. After cooling to ambient temperature, the solution was concentrated by rotary evaporation. The resulting off-white solid was purified by column chromatography on silica gel (150 g, Merck 70-230 mesh) eluting with CHCl3-acetone (9:1, v/v) to collect unreacted 3-bromoaniline (Rf 0.61) and phthalic anhydride (Rf 0.43). Elution with CHCl3-methanol (9:1, v/v) gave the product (Rf 0.38). Selected fractions containing the product were combined and concentrated by rotary evaporation to give 1.53 g of an off-white to light-beige solid. Impure fractions were combined and concentrated by rotary evaporation. The resulting white solid was dissolved in a mixture of CHCl3, acetone, and methanol and re-chromatographed on silica gel (150 g). Elution with CHCl3 removed impurities; the product was then eluted with CHCl3-acetone (4:1, v/v). Selected fractions were combined, concentrated by rotary evaporation, and vacuum dried for 16 h to give 1.41 g of an off-white to light-beige solid, mp 176-179° C., bringing the total yield to 2.94 g (55.8%).

Provenance & Evidence