Calculation of the electron structures and electronic spectra of 3-chloro- and 3-amino-1,2,4-triazole derivatives

3-Chloro- and 3-amino-1,2,4-triazole derivatives were subjected to a theoretical study by means of quantum-chemical calculation by the Pariser-Parr-Pople method. The experimentally observed electron transitions were assigned. The Cl atom and the NH₂ group in the 3 position of 1,2,4-triazole subject the electron system of the heteroring to substantial perturbation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 698–700, May, 1977.     

Acyl derivatives of 3-amino-1,2,4-triazole

Only 3-acylamino-1,2,4-triazoles were isolated in the acylation of 3-amino-1,2,4-triazole with acid chlorides that contain strong electron acceptor substituents. Acylation takes place in the 2 position when aliphatic and aromatic acid chlorides are used as the acylating agents. The action of methoxy- and ethoxyformyl chlorides leads to the formation of 1- and 2-alkoxycarbonyl-3-amino-1,2,4-triazoles. When N-acyl-3-amino-1,2,4-triazoles are heated, they undergo intermolecular trans-aminoacylation to 3-acylamino-1,2,4-triazoles, which exist in the solid phase in the form of amido and imido tautomers. Under the conditions of massspectroscopic analysis the percentage of the imido form increases as the electronacceptor capacity of the substituent increases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1414–1419, October, 1980.     

Vibrational spectra and structure of 1,2,4-triazole derivatives

The frequencies and forms of the normal vibrations of the anions of 1,2,4-triazole and 3-nitro-, 3-nitro-5-methyl-, and 3,5-dinitro-1,2,4-triazoles were calculated. The potential energy constants were calculated by solution of the reciprocal spectral problem, and the frequencies in the experimental spectra were assigned to the fundamental types of normal vibrations. It is shown that the nitro groups in the 3 and 5 positions in the anions of the triazoles are located in the plane of the triazole ring. The coordination of the metal in crystalline salts of nitrotriazoles was studied by the methods of vibrational spectroscopy, and an assumption is stated that the most probable position of the metal is near the oxygen atoms of the nitro group along the Me-O-N line. As a result of a theoretical analysis of the vibrational spectra of the anions it was ascertained that equalization of the lengths of the ring CN bonds does not occur during ionization of the covalent triazoles. Calculations by the MO LCAO SCF method are in agreement with the data from vibrational spectroscopy.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1423–1431, October, 1973.     

Vibrational spectra and structures of 1,2,4-triazole derivatives

The frequencies and forms of the normal vibrations of a number of azido derivatives of 1,2,4-triazole [3-bromo-5-azido-(I), 1-methyl-3razido-(II), and 3-azido-5-nitro-1,2,4-triazole (III)] were calculated. The inverse spectral problem for the parameters of the azido group was solved by the method of least squares. A similar method was used to calculate the potential energy constants of the triazole ring with the aid of data on the force fields of the previously investigated nitrotriazoles. It is shown that the introduction of electron-donor or electron-acceptor substituents in the triazole ring does not affect the force constants of the CN and NN bonds of the azido group. Transmission of the electronic effects in the ring as a function of the nature and position of the substituent was investigated.See [1] for communication V.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 839–842, June, 1977.     

Mass spectra of some 1,2,4-triazole derivatives

Fragmentation of various 1,2,4-triazole derivatives occurs by two predominant pathways involving the loss of RCN originating from both C₃ and C₅ positions. The resulting diazirinium radical cation was observed to lose a nitrogen atom to give a nitrilium ion whose substitution pattern was dependent upon the original substituents in the nucleus.     

Vibrational spectra and structure of 1,2,4-triazole derivatives

The frequencies and forms of the normal vibrations of 3-nitro-1,2,4-triazole, its 1-deuteroand 1-methyl derivatives, and 1-methyl-3-nitro-5-chloro(bromo)-1,2,4-triazole, which are classified as having C_S group symmetry, were calculated. The potential energy constants were refined by solution of the reciprocal spectral problem, and the frequencies in the experimental spectra were assigned to the principal types of vibrations.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 707–712, May, 1973.     

Vibrational spectra and structure of 1,2,4-triazole derivatives

From an analysis of the IR and Raman spectra and a calculation of the frequencies and forms of the normal vibrations of the nitrotriazoles, conclusions have been drawn on the structure of 3,5-dinitro-1,2,4-triazole and 1-methyl-3,5-dinitro-1,2,4-triazole. The nitro group in position 3 of the triazole ring is located in the plane of the molecule, and that in position 5 is rotated about the CN bond. The spatial nonequivalence of the nitro groups leads to the splitting of the absorption bands in the IR spectra that are characteristic for the anti- and synphase vibrations of the nitro groups.For Communication (II), see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1194–1198, September, 1973.     

Vibrational spectra and structures of 1,2,4-triazole derivatives

The vibrational spectra of 1,2,4-triazole and its 3-chloro and 3-bromo derivatives were calculated for the C_S point symmetry group. The potential energy constants were computed, and it is shown that the force field of the triazole ring has the additivity property; i.e., it remains practically constant when electron-acceptor groups such as chlorine and bromine are introduced into the 3 position. The force constants of interaction of the valence and angular coordinates of the ring have high values; this is a characteristic of the considerable rigidity of the triazole ring. The fundamental frequencies in the experimental spectra were assigned on the basis of an analysis of the calculated forms of the normal vibrations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1567–1570, November, 1972.     

Reaction of arylidene derivatives of Meldrum's acid with 3-amino-1,2,4-triazole

The condensation of arylidene derivatives of Meldrum's acid with 3-amino-1,2,4-triazole in nitrobenzene leads to 4,5,6,7-tetrahydro-1,2,4-triazolo [1,5-a]pyrimidin-5-ones. In DMF the reaction proceeds with the formation of arylsubstituted N-(2H-1,2,4-triazol-3-yl)-3-(2H-1,2,4-triazol-3-ylamino)propionamides. Ukrainian Research Institute for the Pharmacotherapy of Endocrine Diseases, Kharkov 310002. Kharkov State University, Kharkov 310077, Ukraine     

Synthesis of 3-Azido-5-amino-1,2,4-triazole

3-Azido-5-amino-1,2,4-triazole was obtained from 3,5-diamino-1,2,4-triazole in two ways: by partial diazotization-substitution directly in the substrate or at its primarily nitrosation, and also with the use of direct or indirect protection of an amino group with subsequent conversion into azido compound followed by deprotection.     

Synthesis and photochemical degradation of N-arylmethyl derivatives of the herbicide 3-amino-1,2,4-triazole

Reaction of an arylmethyl halide with 3-amino-1,2,4-triazole ( 1 ) allows the preparation of the three N-aryl-methyl derivatives of 1 bearing the substituent on the heterocyclic nitrogen atoms. In basic medium (methoxide anion in DMF or methanol, or in benzene by phase transfer catalysis), the isomers 3 and 5 substituted at N-1 and N-2 respectively are obtained, while the isomer 4 is isolated from neutral medium (DMF). The isomers 3 and 4 may be also prepared by cyclization of appropriate formylguanidinium derivatives. 3-Arylmethylamino-1,2,4-triazoles 2 may be obtained through reaction of 3-chloro-1,2,4-triazole ( 6 ) with arylmethylamines. Photolysis of the N-arylmethyl-3-amino-1,2,4-triazoles 2-5 in methanol or water-methanol mixture, induces homolytic and heterolytic cleavage of the arylmethyl-C-N bond giving rise to 3-amino-1,2,4-triazole ( 1 ). Thus, compounds 2-5 with arylmethyl groups able to absorb solar light may be considered as potential photoactivatable herbicides.     

Thermoanalytical study of the pesticide 3-amino-1,2,4-triazole

Thermoanalytical study of the pesticide 3-amino-1,2,4-triazole (ATA) has been carried out, using simultaneous DTA-TG in nitrogen flow, in order to know its thermal behaviour and stability. These techniques have been further complemented using evolved gas analysis and mass spectroscopy (EGA-MS). Two different stages of ATA decomposition were observed: after the first decomposition step, a mixture of compounds is obtained, according to MS data, being the principal component a compound of molecular weight 126. It is formed by a first order reaction mechanism, according to the kinetic study, withE _a=124±8 kJ·mol^?1. The second decomposition step takes place about 735°C, with evolution of HCN and NH₃, being the final weight loss 96%.     

Structure and properties of 3-amino-1-vinyl-1,2,4-triazole

The reaction of acetylene with 3-amino-1,2,4-triazole forms two isomeric 3-amino-N-vinyl-1,2,4-triazoles. Their structures have been studied by PMR and IR spectroscopy and dipole moments. The high activity of the new vinyl compounds of the azole series in the addition of electrophilic reagents, in polymerization, and in complex formation has been shown.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1566–1569, November, 1973.     

N-Amination of 3-amino-1,2,4-triazole with hydroxylamine-O-sulfonic acid: Synthesis of 1,5-diamino-1,2,4-triazole

N-Amination of the 3(5)-amino-1,2,4-triazolide anion with hydroxylamine-O-sulfonic acid is studied. This method provided an access to the previously unknown 1,5-diamino-1,2,4-triazole.     

A novel N-N bond cleavage reaction of 4-amino-1,2,4-triazole derivatives

5-Substituted-4-amino-3-thiol-1, 2, 4-triazoles (1a- b) react with orthonitrochloro- benzene or para-nitrochlorobenzene to give N-N bond cleavage products 2a-d, one structure of which (2b) has been unambiguously confirmed by an X-ray structural analysis.     

Electronic absorption spectra of 2-amino-6-nitro-, 4-amino-3-bromo-and 5-amino-2-bromotoluenes

A new technique—photoacoustic spectroscopy—has been used for the first time to record the u.v.-vis spectra of three substituted toluenes, namely 2-amino-6-nitrotoluene, 4-amino-3-bromotoluene and 5-amino-2-bromotoluene. The π-π* electronic transitions analogous to the benzene first primary and secondary transitions could be detected from the PAS spectra in comparison with the u.v. solution and vapour spectra recorded by conventional methods. Detection of singlet → triplet absorptions from the PAS spectra, with significant intensity, is considered to be an important feature which transitions are in general either not observed or observed with only very weak intensity, in solution or vapour, by conventional methods. The analysis shows that a few excited state combinations observed in the u.v. PAS spectra of the molecules presently studied are well comparable with such combinations in ground state observed in the near i.r. PAS spectra.