反应详情

To a solution of 1-(3,4-dihydroxyphenyl)cyclopropanecarboxylic acid (4.5 g) in MeOH (30 mL) was added TsOH (0.25 g, 1.3 mmol). The stirring was continued at 50° C. overnight before the mixture was cooled to room temperature. The mixture was concentrated under vacuum and the residue was purified by column chromatography on silica gel (petroleum ether/ethyl acetate 3:1) to give 1-(3,4-dihydroxy-phenyl)-cyclopropanecarboxylic methyl ester (2.1 g). 1H NMR (DMSO 300 MHz) δ 8.81 (brs, 2H), 6.66 (d, J=2.1 Hz, 1H), 6.61 (d, J=8.1 Hz, 1H), 6.53 (dd, J=2.1, 8.1 Hz, 1H), 3.51 (s, 3H), 1.38-1.35 (m, 2H), 1.07-1.03 (m, 2H).

1. concentrationThe mixture was concentrated under vacuum
2. customthe residue was purified by column chromatography on silica gel (petroleum ether/ethyl acetate 3:1)