Таутомерія 4-гідразинохіназолінів, коливальні спектри та комп'ютерне моделювання

Tetiana Yu Sergeieva,Sergiy I Kovalenko,Sergiy I Okovytyy,Olexiy Yu Voskoboynik,Jerzy Leszczynski

doi:10.15421/081303

Abstract

The tautomerism of 4-hydrazinoquinazoline and its derivatives was investigated. Geometry and thermodynamic parameters were computed theoretically using Gaussian 03 software. All calculations were performed at the MP2 level of theory using the standard 6-31G(d) basis. Energetics and relative stabilities of tautomers were compared and analyzed in a gas phase. The effect of solvents (1,4-dioxane, acetic acid, ethanol and water) on the tautomeric equlibria was evaluated using PCM. It was determined that solvents induced slight changes in the relative stability. In all cases 4-hydrazinoquinazoline exists predominantly as the amino form. The variation of dipole moments was studied. The anharmonic vibrational wavenumbers for unsubstituted 4-hydrazinoquinazoline were calculated at MP2/6-31G(d) level and compared with experimental data. The modes of IR spectra were assigned. The calculated herein wavenumbers and intensities of amino form are in good agreement with those observed experimentally.

Highlights

The most important route of organic chemistry is searching and synthesis of new compounds with promising properties for different areas
This paper presents the results of quantum-chemical investigation of tautomeric properties in various substituted 4-hydrazinoquinazolines
The geometry optimization and harmonic frequency calculations of the three equilibrium structures for amine/imine tautomerization of 4hydrazinoquinazolines (1-5 (a-c)) were performed employing 6-31G(d) [2] basis set at MP2 level [3] in a gas phase and taking into account solvent effects using PCM model

Summary

Introduction

The most important route of organic chemistry is searching and synthesis of new compounds with promising properties for different areas. TAUTOMERISM OF 4-HYDRAZINOQUINAZOLINES: VIBRATIONAL SPECTRA AND COMPUTATIONAL STUDY The anharmonic vibrational wavenumbers for unsubstituted 4-hydrazinoquinazoline were calculated at MP2/6-31G(d) level and compared with experimental data. The calculated wavenumbers and intensities of amino form are in good agreement with those observed experimentally.

Results

Conclusion