An Unusual Formation of 5-Phenyltetrazole in Reaction of Phenylacetylene with Dimethylammonium Azide

Phenylacetylene reacts with dimethylammonium azide to give a mixture of 4-phenyl-1,2,3-triazole and 5-phenyltetrazole. Formation of 5-phenyltetrazole could be explained by 1,3-cycloaddition of azide to benzonitrile formed by decomposition of 4-phenyl-1,2,3-triazole

A Theoretical and Experimental Study of Dipole Moments of 3-Aminofurazans

Dipole moments of a series of 3-amino-5-R-furazans (R = H, NH2, OCH3, CH3, N3, COOH, COOCH3, NO2) have been determined experimentally and also calculated by means of HF ab initio (STO-3G, 3-21G, 4-31G, 6-31G, 6-31G**/4-31G, 6-31G** levels) and semiempirical (MNDO, AM1, PM3) quantum chemical methods. It was shown that semiempirical AM1 and PM3 methods provide generally good agreement with the experimental values of dipole moments. On the other hand, a satisfactory description of this aminofurazan property by ab initio method is observed only in the case of calculation levels with the electron correlation and the polarization function included. For these compounds amino-imino tautomeric equilibrium is strongly shifted towards the amino-form. 3-Aminofurazan-4-carboxylic acid and its methyl ester exist in dioxane or benzene solutions at least as a mixture of two different s-cis- and s-trans-conformers stabilized by conjugation and hydrogen bonding

Spectral and density functional studies on the absorbance and fluorescence spectra of 2-R-5-phenyl-1,3,4-oxadiazoles and their conjugate acids

Absorption and fluorescence spectra of 2-R-5-phenyl-1,3,4-oxadiazoles (R = H, methyl, tert-butyl, trifluoromethyl, amino, phenyl, benzyl) were studied experimentally and by time dependent density functional theory (TDDFT) methods. In acidic media a substantial red shift is observed due to the presence of conjugate acid forms. Two conjugate acid forms (3H and 4H) are possible for unsymmetrically substituted oxadiazoles. Relative basicities of the two basic centers of oxadiazole ring at the S-0 and S-1 geometries were calculated using the local density descriptors approach. Substituent effects were studied by analyzing the electron density distribution in the ground and excited states. Analyzing the absorption spectra and local descriptors results, we predict 4H forms to be the dominant acid forms. Calculated emission peaks of 4H forms agree well with experimental observations. An abnormal red shift in the case of the 3H forms is attributed to the increased stabilization of the N-H bond in the 3H forms compared to the 4H forms

5-Vinyl-1H-tetrazole

Highly purified 5-vinyl-1H-tetrazole was synthesized, which is in great demand in modern medicine and industry as a monomer for obtaining nitrogen-rich macromolecular compounds and a reagent for the complete synthesis of biological compounds. The molecular structure was studied experimentally with sequential X-ray diffraction analysis and theoretically with ab initio quantum chemical calculations. The data from differential scanning calorimetry, nuclear magnetic resonance (1H, 13C, 1H-15N, HMBC), high-resolution mass spectrometry and vibrational spectroscopy were analyzed. The results are useful for evaluating the possibility of extending the polymerization of 5-vinyl-1H-tetrazole to synthesize polymers with predictable molecular weight and thermodynamic parameters