反应详情

2.44 g of N-[4 -(β-<2-methoxy-5-methyl-benzamido>-ethyl)-benzenesulfonyl]-N'-cyclopentyl-methyl-thio-urea (I) were dissolved together with 1.03 g of dicyclohexylcarbodiimide in 20 ml of hot dioxane. The whole was allowed to cool and to stand for several days. Thereupon, the N,N'-dicyclohexyl-thiourea that had formed (melting point 176° - 178° C) was filtered off with suction. The filtrate which contained the N-[4-(β-<2-methoxy-5-methyl-benzamido>ethyl)-benzenesulfonyl]-N'-cyclopentyl-methyl-carbodiimide (II) in dissolved state, was combined with about 5 ml of water. The whole was shortly heated on a water bath and concentrated. The residue was dissolved in a mixture of toluene, ether and dilute aqueous ammonia, while shaking. The aqueous phase was separated. The toluene/ether phase was extracted again with dilute ammonia. The aqueous extracts were united and acidified. There was obtained a precipitate, constituting the N-[4-(β-<2-methoxy-5-methyl-benzamido>-ethyl)-benzenesulfonyl]-N'-cyclopentylmethylurea (III). After recrystallization from methanol, the sulfonylurea was found to melt at 148° - 150° C.

1. temperatureto cool
2. waitto stand for several days