Die Acylierung von 5‐Amino‐1 H‐1, 2, 4‐triazolen. Eine 13C‐NMR.‐Studie

Abstract

The Acylation of 5‐Amino‐1 H‐1,2,4‐triazoles. A 13C‐NMR. StudyThe acylation of 3‐substituted‐5‐amino‐1 H‐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‐1 H‐1,2,4‐triazole (1b, 1c and 1d) with methyl chloroformate gave up to 10% 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.