A theoretical study of annular tautomerism of pyrrolotetrazoles in the gas phase

作者：Zubarev Vadim Yu; Trifonov Rostislav E; Ostrovskii Vladimir A^*; Moderhack Dietrich

来源：Chemistry of Heterocyclic Compounds, 2015, 51(3): 246-249.

DOI：10.1007/s10593-015-1692-7

• pyrrolotetrazoles
• aromaticity
• HF and DFT calculations
• tautomerism
• total energies

[GRAPHICS]
The structure and tautomerism of pyrrolotetrazoles have been studied with quantum-chemical methods (HF/6-31G** and DFT B3LYP/ANO-S) in the gas phase. According to the calculations of the total energies of various prototropic forms of these heterocyclic systems (1H-, 3H-, 5H- and 7H-tautomers), it was shown that for unsubstituted pyrrolotetrazole and its derivatives containing methyl substituents at the carbon atom(s), the most stable form is the 5H-tautomer where aromaticity of the tetrazole fragment is maintained. On the contrary, for pyrrolotetrazoles with electron-withdrawing substituents (CN or Cl), the most stable form is the 1H-tautomer, where the pyrrole fragment is aromatic. This effect may be determined by the differences of the relative electron accepting of the heterocyclic half-rings.

• 出版日期2015-3
• 单位河北医科大学