Water → N-(1-isobutyl-2-pyrrolidinylmethyl)-2-methyl-5-sulfamoyl-2,3-dihydrobenzofuran-7-carboxamide

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Reaction Steps

A suspension of 5.2 g of methyl 2-methyl-5-sulfamoyl-2,3-dihydrobenzofuran-7-carboxylate and 4.5 g of 1-isobutyl-2-aminomethylpyrrolidine in 20 ml of diethylene glycol is heated at 130°-140° C. and stirred for 18-19 hours. The reaction solution is cooled to room temperature and poured into 150-200 ml of water while stirring. Under ice-cooling crystals are deposited thoroughly and collected by suction filtration. The crude crystals are washed with cold water, dissolved in chloroform and separated on a column of silica gel (developing solvent: methanol/chloroform=1/9). Crystals obtained are recrystallized from about 35 ml of methanol to give crystals of N-(1-isobutyl-2-pyrrolidinylmethyl)-2-methyl-5-sulfamoyl-2,3-dihydrobenzofuran-7-carboxamide, m.p. 182°-184° C.

Provenance & Evidence