Acetic Acid → 2-methylthio-5,6,7,9-tetrahydrothiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-one

Reaction equation

[NH2:1][C:2]1[NH:6][N:5]=[C:4]([S:7][CH3:8])[N:3]=1.O=[C:10]1[CH:15]([C:16](OCC)=O)[CH2:14][CH2:13][S:12][CH2:11]1.C(O)(=[O:23])C>>[CH3:8][S:7][C:4]1[N:3]=[C:2]2[N:1]=[C:14]3[C:13](=[O:23])[S:12][CH2:11][CH:10]=[C:15]3[CH2:16][N:6]2[N:5]=1

Participants

Reactant 3

HCID 176Acetic Acid

HCID 784713-(Methylthio)-1,2,4-triazol-5-amine

HCID 15049900Ethyl 3-oxothiane-4-carboxylate

Product 1

HCID 199886062-methylthio-5,6,7,9-tetrahydrothiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-oneYield 62.9%

Procedure

0.976 g (0.0075 mole) of 5-amino-3-methylthio-1H-1,2,4-triazole are dissolved in 6 ml of acetic acid, then 1.368 g (0.075 mole) of ethyl 3-oxo-3,4,5,6-tetrahydro-2H-thiopyrane-4-carboxylate are added and the reaction mixture is boiled for 30 minutes. The precipitated product is filtered off from the hot solution, washed with water and recrystallized from dimethylformamide. Thus 1.2 g (62.9%) of 2-methylthio-5,6,7,9-tetrahydrothiopyrano[3,4-d]-1,2,4-triazolo[1,5-a]pyrimidine-5(10H)-one are obtained which melt at 294°-297° C.