Synthesis
General method: 4-substituted benzenesulfonamides were dissolved in anhydrous dichloromethane and the solution was cooled to 0°C in an ice bath. Subsequently, trimethylamine was slowly added dropwise to the reaction system. The reaction temperature was maintained at 0 °C and after continuous stirring for 10 min, methyl chloroformate was added dropwise. Stirring of the reaction mixture was continued at 0°C for 30 minutes. The ice bath was removed and the reaction mixture was allowed to gradually warm up to room temperature over 2 hours. Upon completion of the reaction, the reaction mixture was diluted with dichloromethane and the organic phase was washed sequentially with 1 M aqueous hydrochloric acid, water and saturated brine. The organic layer was dried with anhydrous magnesium sulfate and subsequently concentrated under reduced pressure. The residue was purified by silica gel column chromatography to afford the target product, methyl 4-substituted (phenylsulfonyl)carbamate.
References
[1] Journal of the Chinese Chemical Society, 2007, vol. 54, # 3, p. 771 - 777
[2] Organic Process Research and Development, 2016, vol. 20, # 2, p. 440 - 445
[3] Tetrahedron Letters, 2016, vol. 57, # 13, p. 1476 - 1478
[4] Journal of Medicinal Chemistry, 2004, vol. 47, # 3, p. 627 - 643
[5] Journal of Medicinal Chemistry, 2017, vol. 60, # 3, p. 1126 - 1141
