The Acylation of 5-Amino-1H-1,2,4-triazoles. A 13C-NMR.-Study

Article abstract of DOI:10.1002/hlca.19830660233

The acylation of 3-substituted-5-amino-1H-1,2,4-triazoles (1) with methyl chloroformate or dimethylcarbamoyl chloride yielded mainly 1-acyl-5-amino-1,2,4-triazoles (2 and 3).Acylation of 3-methyl-, 3-methoxy- and 3-methylthio-5-amino-1H-1,2,4-triazole (1b, 1c and 1d) with methyl chloroformate gave up to 10percent of the 1-acyl-3-amino-1,2,4-triazoles.For the unsubstituted 5-amino-1,2,4-triazole (1a), a (1:1)-mixture of the 3- and 5-isomers 2a and 4 was obtained in dioxane in the presence of triethylamine.No 4-acylated product was detected in contrast to earlier reports.The structures of the reaction products were determined with the aid of proton coupled 13C-NMR. spectra using the corresponding N-methyl-1,2,4-triazoles as reference compounds.