反应详情

1.30 g (0.01 mole) of 5-amino-3-methylthio-1H-1,2,4-triazole are dissolved in 6 ml of acetic acid, then 1.88 g (0.01 mole) of ethyl 4-oxo-3,4,5,6-tetrahydro-2H-thiopyrane-3-carboxylate are added and the reaction mixture is boiled for 60 minutes. The precipitated product is filtered off from the hot solution and washed with i-propanol. The 1.6 g (63%) of 2-methylthio-5,6,8,9-tetrahydrothiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-one thus obtained are dissolved in 12 ml of hot 10% sodium hydroxide solution and after cooling down the precipitated 2-methylthio-5,6,8,9-tetrahydrothiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-one sodium salt is filtered off (melting point: higher than 350° C.), then dissolved in 30 ml of distilled water. Thereafter the solution is made highly acidic with the aid of acetic acid and the 2-methylthio-5,6,8,9-tetrahydrothiopyrano[4,3-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-one is precipitated again.

1. filtrationThe precipitated product is filtered off from the hot solution
2. washwashed with i-propanol