反应详情

Five point six (5.6) grams of the thus obtained 2-amino-5-benzylthio-1,3,4-thiadiazole and 3.6 g of ethyl 3-hydroxy-2-methyl-2-propenoate were mixed with 7.5 g of polyphosphoric acid, and the mixture was stirred at 130°-150° C. for 45 minutes. After cooling, water was added to the reaction mixture, and the mixture was extracted with chloroform. The organic layer was washed with an aqueous sodium hydrogen carbonate solution and water respectively, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was recrystallized from ethanol. Thus 4.4 g of 2-benzylthio-6-methyl-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one was obtained. m.p. 130°-132° C. Yield 61%.

1. temperatureAfter cooling
2. extractionthe mixture was extracted with chloroform
3. washThe organic layer was washed with an aqueous sodium hydrogen carbonate solution and water respectively
4. dry with materialdried over anhydrous sodium sulfate
5. distillationThe solvent was distilled off
6. customthe residue was recrystallized from ethanol