General procedure for the synthesis of 3-chloro-5-methoxyphenol from 1-chloro-3,5-dimethoxybenzene (Scheme No. 4, K): 1-methyl-2-pyrrolidinone (75 mL) was added to sodium methanethiol (12.32 g, 173.80 mmol) followed by 1-chloro-3,5-dimethoxybenzene (20.00 g, 115.87 mmol). The reaction mixture was heated to 140°C and maintained for 2.5 hours, followed by stirring at room temperature overnight. Upon completion of the reaction, 1-methyl-2-pyrrolidinone was removed by distillation under reduced pressure. The residue was partitioned between ethyl acetate, water and 1N hydrochloric acid. The organic layer was sequentially washed twice with 1N hydrochloric acid and once with saturated aqueous sodium chloride solution and then dried with anhydrous magnesium sulfate. The organic solvent was removed by concentration under reduced pressure to give a pale yellow solid. The solid was purified by silica gel column chromatography (400 mL silica gel, dichloromethane as eluent). The purified fraction was collected and the solvent was removed under reduced pressure to give 3-chloro-5-methoxyphenol as a yellow solid (16.62 g, 90% yield).1H NMR (300 MHz, DMSO-d6) δ 6.43 (t, J = 2.0 Hz, 1H), 6.40 (t, J = 1.9 Hz, 1H), 6.28 (t, J = 2.1 Hz, 1H), 6.28 (t, J = 2.1 Hz, 1H) 3.71 (s, 3H); MS (APCI+) m/z 159 [M+1]; Rf = 2.04 min.
