99-76-3

3337-59-5

The general procedure for the synthesis of methyl 3,5-dichloro-4-hydroxybenzoate from methyl nipagin was as follows: 4-hydroxybenzoic acid (0.2 g; 1.3 mmol) was mixed with N-chlorosuccinimide (0.37 g; 2.76 mmol) in anhydrous dichloromethane (15 ml) at room temperature, followed by the addition of titanium tetrachloride (0.1 ml; 0.9 mmol) . The reaction mixture was stirred for 5 hours. After completion of the reaction, ice (about 10 g) was added and stirring was continued for 30 min at room temperature. The mixture was diluted with ethyl acetate to 100 ml. The organic phase was separated, washed sequentially with water (2 x 10 ml) and brine (10 ml), dried over anhydrous magnesium sulfate and filtered, and the filtrate was concentrated to dryness. The residue was purified by silica gel column chromatography (dichloromethane as eluent) to afford methyl 3,5-dichloro-4-hydroxybenzoate (0.19 g; 65% yield) as a colorless solid. The 1H-NMR (CDCl3) data were as follows: δ 7.96 (s, 2H), 6.18 (s, 1H), 3.89 (s, 3H).