Recyclization of Pyrimidinium Salt – A Method for the Synthesis of Derivatives of Nitrogen-Containing Heterocycles

By recyclization of 1,4,6-trimethyl-2-ethoxycarbonylmethylpyrimidinium iodide under the action of ethylhydrazine and 4,6-dimethylpyrimidinyl-2-acetic acid hydrazide, 1-ethyl-3-ethoxycarbonylmethyl-5-methyl-1,2,4-triazole and 5,7-dimethyl-3-ethoxycarbonyl-2-(4,6-dimethyl-yrimidinyl-2)methylpyrazolol1,5-alpyrimidine were synthesized, respectively. Alkylation of 1-ethyl-3-ethoxycarbonylmethyl-5-methyl-1,2,4-triazole with various alkyl iodides yielded the corresponding N-alkyltriazolium salts, and reactions of triazolylacetic acid esters yielded their hydrazides. Based on the nuclear Overhauser effect (NOE), it was clearly demonstrated that alkylation occurs at the N-4 nitrogen atom of the triazole ring.