反应详情

A solution of 4-chloro-2-ethoxy-5-methanesulfonylbenzoic acid (2.5 g, 9.0 mmol) in tetrahydrofuran was cooled to 5° C. and treated with excess diazomethane in ether solution (prepared from N-methyl-N-nitroso-p-toluenesulfonamide, Aldrich) and stirred for 10 min. Solvent and excess diazomethane was removed by rotary evaporation. The resulting residue was dissolved in dichloromethane and filtered through a plug of silica gel and evaporated. The solids were triturated with ether/hexane to give 4-chloro-2-ethoxy-5-methanesulfonyl-benzoic acid methyl ester (2.1 g, colorless solids).

1. customSolvent and excess diazomethane was removed by rotary evaporation
2. dissolutionThe resulting residue was dissolved in dichloromethane
3. filtrationfiltered through a plug of silica gel
4. customevaporated
5. customThe solids were triturated with ether/hexane