Water → Ethyl 2-chloro-5-[3-(2-ethoxycarbonyl-1-cyclopenten-1-yl)ureido]-benzoate

Participants

Reaction Steps

48.4 g of ethyl 2-chloro-5-ureido-benzoate and 31.2 g of ethyl cyclopentanone-2-carboxylate are heated at reflux temperature for 6 hours in 500 ml of benzene and 2 g of toluene-4-sulphonic acid monohydrate. The water formed is removed by means of a water separator. The reaction mixture is subsequently evaporated to dryness. the residue is dissolved in 700 ml of diethyl ether and the solution is filtered. The filtrate is evaporated to dryness and the residue is purified by chromatography on 1.5 kg of silica gel using diethyl ether/n-hexane (1:2) as the eluent. Ethyl 2-chloro-5-[3-(2-ethoxycarbonyl-1-cyclopenten-1-yl)-ureido]-benzoate is obtained as colourless crystals. The product is recrystallized from diethyl ether/n-hexane, m.p. 110°-112° C.

Provenance & Evidence