Synthesis and structure of condensed biheterocycles on the basis of 3-amino-1,2,4-triazole

Abstract

The article is devoted to the development of preparatively convenient methods for the synthesis of new derivatives of 3-amino-1,2,4-triazole with the aim of constructing new condensed systems of industrially important substances. The synthesis of triazolopyrimidines, prepared by three-component condensation of 1,3-dicarbonyl compounds (anilide of acetoacetic acid and acetoacetic ether) with substituted aromatic aldehydes and 3-amino-1,2,4-triazole. It is shown that by melting at 120–140 ºC, in the absence of a solvent in equimolecular amounts of acetylacetyl anilide and acetoacetic ether with a mixture of 3-amino-1,2,4-triazole and substituted aromatic aldehydes (3-ethoxy-4-hydroxybenzaldehyde, salicylic aldehyde), leads to the 7-aryl-5- methyl-N-phenyl-4,7-dihydro-[1,2,4-triazolo][1,5-a]pyrimidine-6-carboxamides and ethyl 7-aryl-5-methyl- 4,7-dihydro-[1,2,4-triazolo][1,5-a]pyrimidin-6-carboxylate-titrate respectively. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy, as well as with the data of the twodimensional spectra of COSY (1H-1H) and HMQC (1H-13C). The values of chemical shifts, multiplicity and integrated intensity of the 1H and 13C signals in one-dimensional NMR spectra are determined. Homo- and heteronuclear interactions were established using spectra in the formats COSY (1H-1H) and HMQC (1H-13C), confirming the structure of the compounds under study.