Quantum chemical studies of pyrimidin-4-ones Part 6. On peculiarities of the reactions with nitrating agents of some carboxylic acids of the thieno[2,3-d]pyrimidin-4-one series and their esters

详细信息    查看全文

• 作者：M. Kh. Mamarakhmonov ; L. I. Belen’kii ; N. D. Chuvylkin…
• 关键词：Key words2 ; 3 ; and 5 ; substituted 6 ; carboxylic acids and ethyl esters of thieno[2 ; 3 ; d]pyrimidin ; 4 ; ones ; nitration reactions ; quantum chemical calculations ; Hartree—Fock method ; DFT/B3LYP/3 ; 21G method ; IEFPCM approximation
• 刊名：Russian Chemical Bulletin
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：65
• 期：3
• 页码：654-657
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry/Food Science, general; Organic Chemistry; Inorganic Chemistry;
• 出版者：Springer US
• ISSN：1573-9171
• 卷排序：65

文摘

Quantum chemical calculations of the energies, electronic structures, and molecular geometries of 5-methyl-, 2,5-dimethyl-, 3,5-dimethyl-, and 2,3,5-trimethyl-4-oxothieno[2,3-d]pyrimidine-6-carboxylic acids; 5-methyland 3,5-dimethyl-2,4-dioxothieno[2,3-d]pyrimidine6-carboxylic acids; 5-methyland 3,5-dimethyl-4-oxo-2-thiothieno[2,3-d]pyrimidine-6-carboxylic acids; and their ethyl esters were performed in terms of the HF and DFT (B3LYP) approximations in the 3-21G basis set. The reactions routes with nitrating agents were examined, and the factors governing the direction of the reactions, the probability of their occurrence were determined. Selective ipso-substitution of the 5-methyl group by the nitro group at the C(5) atom of the thiophene fragment is hindered for all compounds studied. The reasons for the unfavorable ipso-substitution were discussed taking into account effects of solvents and substituents in positions 2, 3, and 6 of 6-carboxyand 6-ethoxycarbonyl-substituted thieno[2,3-d]pyrimidin-4-ones.