反应详情

A mixture of 5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-1(2H)-pyrimidinyl]-1, 2-benzisothiazole-3-carboxaldehyde(0.500 g, 0.00141 mol), 2,4-dimethyl-2,4-pentanediol (0.260 g, 0.00183 mol), p-toluenesulfonic acid (0.0100 g, 0.000071 mol) and toluene is stirred overnight at reflux with azeotropic removal of water. The mixture is cooled to room temperature, diluted with diethyl ether and ethyl acetate and washed with two prortions of water and brine. The organic layer is dried and concentrated in vacuo to a brown oil, which is chromatographed on silica gel with ethyl acetate-hexanes to afford the title compound as a white solid (0.200 g, 31.4%, mp 88-92° C.) which is characterized by NMR spectral analysis.

1. washwashed with two prortions of water and brine
2. customThe organic layer is dried
3. concentrationconcentrated in vacuo to a brown oil, which
4. customis chromatographed on silica gel with ethyl acetate-hexanes