A. N. Egorochkin

A new method of synthesizing mesoionic 1,2,4-triazole-3-thiones and their spectra

Mesoionic 1,2,4-triazole-3-thiones have been synthesized by the reaction of 1-acyl-1-arylhydrazines and 1-acyl-1-alkylhydrazines with isothiocyanates in the presence of triethylamine. The structure of the compounds obtained has been confirmed by a study of their UV, IR, PMR, and mass spectra.

PMR spectra of some mesoionic heterocycles

Conclusions1.In the PMR spectra of mesoionic azoles the deshielding effect of CF3CO2H as the solvent is related to the protonation of the azole molecule, while the deshielding effect of DMSO is related to the formation of the H5-DMSO bond.2.The effect of exo-and endocyclic groupings on the shielding of the proton in the 5 position of mesoionic azoles is explained mainly by mesomeric effects.

Study of charge-transfer complexes of mesoionic 1,3,4-oxa-, thia-, and triazoles by electronic absorption spectroscopy

1. n nThe spectra of the charge-transfer complexes of mesoionic 1,3,4-oxa, thia, and triazoles with various exocyclic groups and tetracyanoethylene have been obtained. n n n n n2. n nThe position of the charge-transfer band provides information on the relative donor capacity of the exocyclic groups.

Behavior of exocyclic selenone group in mesoionic 1,3,4-triazoles

1. n nThe exocyclic selenium atom is cleaved and the triazolium salt is formed when the mesoionic 1,3,4-triazoleselen-2-one is oxidized. n n n n n2. n nA new 1,3,4-triazoleselen-2-one dibromide system was synthesized and some of its properties were studied.

Mesoionic 1-amino-1,3,4-triazole-2-thiones and their azomethine derivatives

The reaction of triethylammonium salts of α-acyldithiocarbazic acids with sodium chloroacetate and hydrazine leads to the formation of mesoionic 1-amino-1,3,4-triazole-2-thiones, which react with aldehydes to give the corresponding azomethine derivatives.