反应详情

A solution of intermediate 4, 6-benzyloxy-2,5-dioxo-1,2,3,5-tetrahydro-imidazo[1,2-a]pyrimidine-7-carboxylic acid ethyl ester, (0.770 g, 2.34 mmol) in trifluoroacetic acid (20 ml) was stirred at 25° C. for 1 h. The solvent was then evaporated under reduced pressure and residual trifluoroacetic acid removed by azeotropic distillation with toluene in vacuo. Acetic acid (5 ml) was added and the mixture subjected to azeotropic distillation with toluene in vacuo to remove solvent and residual acid. Recrystallization of the solid residue from ethyl acetate gave 0.497 g (88% yield) of the title ester as white crystals; mp 265° C. (dec).

1. customThe solvent was then evaporated under reduced pressure and residual trifluoroacetic acid
2. customremoved by azeotropic distillation with toluene in vacuo
3. additionAcetic acid (5 ml) was added
4. distillationthe mixture subjected to azeotropic distillation with toluene in vacuo
5. customto remove solvent and residual acid
6. customRecrystallization of the solid residue from ethyl acetate