The general procedure for the synthesis of 2-bromo-4,5-dimethoxyphenol from 3,4-dimethoxyphenol was as follows: 4-bromoanisole (200.8 mg, 1.09 mmol, 1.0 eq.) was dissolved in acetonitrile (2 mL) at room temperature, followed by addition of N-chlorosuccinimide (NCS) (158.3 mg, 1.19 mmol, 1.1 eq.) , a slightly turbid mixture was obtained. Next, chlorotrimethylsilane (TMSCl) (14 μL, 0.11 mmol, 0.1 eq.) was added dropwise to the reaction mixture. Within a few minutes, the reaction mixture was transformed into a clarified pale yellow solution. Stirring of the reaction mixture was continued at room temperature for 1 h, after which it was diluted with hexane. The two-phase mixture was concentrated on a rotary evaporator to give a crude white solid-oil mixture. This mixture was dissolved in hexane, filtered through a short silica gel column and eluted with 5-10% ethyl acetate-hexane solution. Concentration of the clarified filtrate afforded a mixture of 4-bromo-2-chloro-1-methoxybenzene (2a-Cl) and 2,4-dichloro-1-methoxybenzene (2a-diCl) in a yield of 237.0 mg (based on NMR analysis of a ratio of 2a-Cl to 2a-diCl of 7.1:1.0, with 88% yield of 2a-Cl and 11% yield of 2a-diCl ), and the product was a light yellow solid.
