Pyrolytic elimination of ethylene from ethoxyquinolines and ethoxyisoquinolines: a computational study.

This work reports a thermo-kinetic study on unimolecular thermal decomposition of some ethoxyquinolines and ethoxyisoquinolines derivatives (1-ethoxyisoquinoline (1-EisoQ), 2-ethoxyquinoline (2-EQ), 3-ethoxyquinoline (3-EQ), 3-ethoxyisoquinoline (3-EisoQ), 4-ethoxyquinoline (4-EQ), 4-ethoxyisoquinoline (4-EisoQ), 5-ethoxyquinoline (5-EQ), 5-ethoxyisoquinoline (5-EisoQ), 8-ethoxyquinoline (8-EQ) and 8-ethoxyisoquinoline (8-EisoQ)) using density functional theory DFT (BMK, MPW1B95, M06-2X) and ab initio complete basis set-quadratic Becke3 (CBS-QB3) calculations. In the course of the decomposition of the investigated systems, ethylene is eliminated with the production of either keto or enol tautomer. The six-membered transition state structure encountered in the path of keto formation is much lower in energy than the four-membered transition state required to give enol form.

Structures, Energetics, and Spectra of (NH) and (OH) Tautomers of 2-(2-Hydroxyphenyl)-1-azaazulene: A Density Functional Theory/Time-Dependent Density Functional Theory Study.

Tautomerization of 2-(2-hydroxyphenyl)-1-azaazulene () in the gas phase and ethanol has been studied using B3LYP, M06-2X, and ωB97XD density functional theory (DFT) with different basis sets. For more accurate data, energies were refined at CCSD(T)/6-311++G(2d,2p) in the gas phase. Nuclear magnetic resonance (NMR), aromaticity, Fukui functions, acidity, and basicity were also calculated and compared with experimental data.