反应详情

0.51 g of methyl isocyanate and subsequently one drop of triethylamine are added at room temperature while stirring to a solution of 2.00 g of 3-(4-chloro-2-fluoro-5-hydroxyphenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione in 20 ml of methylene chloride. The reaction mixture is stirred for one hour and evaporated to dryness under reduced pressure. The residue is purified by chromatography on a silica gel column using diethyl ether-n-hexane (2:1) as the eluent. There is obtained 2-chloro-5-[3,6-dihydro-2,6-dioxo-3-methyl-4-trifluoromethyl-1(2H)-pyrimidinyl]-4-fluorophenyl methylcarbamate, 1H-NMR (CDCl3, 400 MHz): 7.33 ppm (d,1H), 7.24 ppm (d,1H), 6.34 ppm (s,1H), 5.21 ppm (q,1H), 3.54 ppm (d,3H), 2.88 ppm (d,3H).

1. customevaporated to dryness under reduced pressure
2. customThe residue is purified by chromatography on a silica gel column