反应详情

from 4-chloro-2-fluoro-5-isopropoxyphenylurea and ethyl acetoacetate using finely powdered Amberlyst®-15 (an organic, polymeric resin having free sulphonyl groups) as the catalyst there is obtained ethyl 3-[3-(4-chloro-2-fluoro-5-isopropoxyphenyl)ureido]crotonate, m.p. 142°-144° C. and from this intermediate in dimethylformamide with sodium hydride there is obtained 3-(4-chloro-2-fluoro-5-isopropoxyphenyl)-6 -methyl-2,4(1H,3H)-pyrimidinedione, m.p. 228°-230° C.;