反应详情

7.00 g of 4-chloro-2-fluoro-5-isopropoxyphenylurea and 4.44 g of ethyl cyclopentanone-2-carboxylate are heated at reflux temperature for 1.5 hours with 0.3 g of toluene-4-sulphonic acid monohydrate in 150 ml of benzene. The water which forms is removed with a water separator. The reaction mixture is subsequently evaporated to dryness and the residue is purified by chromatography on a silica gel column using methylene chloride as the eluent and recrystallized from diethyl ether/n-hexane. There is obtained ethyl 2-[3-(4-chloro-2-fluoro-5 -isopropoxyphenyl)-ureido]-1-cyclopentenecarboxylate, m.p. 166°-169° C.

1. customThe water which forms is removed with a water separator
2. customThe reaction mixture is subsequently evaporated to dryness
3. customthe residue is purified by chromatography on a silica gel column
4. customrecrystallized from diethyl ether/n-hexane