Benzyl Bromide → Benzyl 6,7-dichloro-4H-1-benzopyran-4-carboxylate

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Reaction Steps

A mixture of 6,7-dichloro-4H-1-benzopyran-4-carboxylic acid (16.8 gm), tetra (N-butyl)ammonium hydrogensulfate (23 gm), benzyl bromide (9.7 mL), saturated sodium bicarbonate (100 mL) and dichloromethane (100 mL) were stirred vigorously at room temperature for 14 hours, then diluted with dichloromethane, and the organic layer separated, washed with saturated sodium bicarbonate, water, brine, dried (MgSO4), filtered and evaporated. The residue was purified by column chromatography (2:1 dichloromethane/hexanes, SiO2) to afford the title compound (11.8 gm, Rf=0.3 (2:1 dichloromethane/hexanes, SiO2).

Provenance & Evidence