Acetone → 1-(2-Chlorophenyl)-2-hydroxy-2-methylpropane-1-sulfonamide

Participants

Reaction Steps

Under inert gas, 1.51 g of C-(2-chlorophenyl)-N-(2,4-dimethoxybenzyl)methanesulfonamide were initially charged in 30 ml of THF, and then, at a temperature of −78° C., 6.09 ml of a 1.6 N methyllithium solution in diethyl ether were added dropwise and the mixture was stirred at constant temperature for 10 minutes. Subsequently, 1.83 ml of acetone were added. After stirring for 10 minutes, the reaction solution was admixed with 2 ml of trifluoroacetic acid and the solvent was removed under reduced pressure. The residue was dissolved in ethyl acetate, and the solution was washed with saturated aqueous sodium hydrogencarbonate solution and water, dried over MgSO4 and concentrated by rotary evaporation. The residue was dissolved in 20 ml of dichloromethane, and 3 ml of trifluoroacetic acid were added. After stirring at room temperature for 2 hours, the reaction solution was concentrated by rotary evaporation and the residue was taken up in a mixture of water and dichloromethane. The solid which precipitates out was analyzed by LCMS and 1H NMR and subsequently discarded, since no product was present. Another solid precipitated out of the filtrate, which was identified by LCMS as product-containing (512 mg). Since further product was present in both phases of the filtrate, the aqueous phase was extracted with dichloromethane, the combined organic phases were concentrated by rotary evaporation and the residue was purified by means of normal phase chromatography using a Flashmaster with an n-heptane/ethyl acetate gradient. The product-containing fractions were combined and concentrated by rotary evaporation (707 mg). This gave the product with a molecular weight of 263.7 g/mol (C10H14ClNO3S); MS (ESI): m/e=283 (M+H2O+H+).

Provenance & Evidence