M. Mamarakhmonov, L. I. Belen´kii, N. D. Chuvylkin
Nov 19, 2015
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Journal
Russian Chemical Bulletin
Abstract
Quantum chemical calculations of energies, electronic structures, and molecular geometries of 3,5,6-trimethylthieno[2,3-d]pyrimidin-4-one (1), tricyclic 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-substituted 5,6-dimethylthieno[2,3-d]pyrimidin-4-ones (2—4), carboxylic acids 5—8 resulting from oxidation of compounds 1—4 at the methyl group in position 5 of thienopyrimidine, methyl esters of these acids (9—12), and products of ipso-nitration of esters (13—16) were performed in terms of the HF and DFT (B3LYP) approximations with the 3-21G basis set. Also, calculations for mixed anhydrides of nitric acid and carboxylic acids 17—20 were carried out. The possible causes of differences in the behaviors of 3-unsubstituted and 3-substituted thieno[2,3-d]pyrimidin-4-ones were discussed.