Sulfuric Acid → 5-Ethylthio-7-phenyl-1,2,4-triazolo[4,3-c]pyrimidine dihydrogen sulfate hydrate

Reaction equation

[CH2:1]([S:3][C:4]1[N:9]2[CH:10]=[N:11][N:12]=[C:8]2[CH:7]=[C:6]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[N:5]=1)[CH3:2].[S:19](=[O:23])(=[O:22])([OH:21])[OH:20].C(OCC)C>C(O)C>[OH2:20].[S:19]([OH:23])([OH:22])(=[O:21])=[O:20].[CH2:1]([S:3][C:4]1[N:9]2[CH:10]=[N:11][N:12]=[C:8]2[CH:7]=[C:6]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[N:5]=1)[CH3:2]

Participants

Procedure

To a solution of 3.6 g of 5-ethylthio-7-phenyl-1,2,4-triazolo[4,3-c]pyrimidine in 100 ml of hot ethanol was added 1.4 g of concentrated sulfuric acid. The mixture was cooled, an equal volume of diethyl ether was added and the precipitate was collected by filtration. The precipitate was recrystallized from a mixture of methanol and diethyl ether to provide 5-ethylthio-7-phenyl-1,2,4-triazolo[4,3-c]pyrimidine dihydrogen sulfate hydrate, m.p. 213°-214° C. Analysis: Calculated for C13H12N4S.H2SO4 2/3 H2O: %C, 50.4; %H, 4.1; %N, 13.1; Found: %C, 50.4; %H, 4.4; %N, 13.1