Tautomerism and the spectroscopic properties of some 4,6-disubstituted pyrimedines

Berndt, M.; Ingwer, M.; Kwiatkowski, Józef S.

doi:10.1016/0022-2860(73)85268-8

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…Short and Thompson based on IR spectroscopy data suggested that in the solid state, it is in the lactam–lactim and dilactam forms (Figure , 2a , 2b , 2c , 2d ). Based on nuclear magnetic resonance (NMR) and UV spectroscopy data, a number of Russian and Australian researchers also tended to prefer the existence of form 2a in solutions in organic solvents. − Although this form dominates the solution, a small amount of dilactam ( 2c ) , is allowed. Khromov–Borisov based on NMR spectroscopy data and Katritzky based on basicity measurements suggested that zwitterionic forms (Figures and , 2e , 4a – d ) are important in aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Study of the Basicity of 4,6-Dihydroxypyrimidine Derivatives

Yudin

Kushtaev

et al. 2021

ACS Omega

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The protonation of a number of 4,6-dihydroxypyrimidine derivatives is studied, and the features of the electronic spectra of free bases and protonated forms are considered. It is shown that the alkyl substituents in position 2 increase the basicity of the compound, and the nitro group in position 5 leads to its decrease. In an acid medium (0.1−99.5% H 2 SO 4 ), 4,6dihydroxypyrimidine, 6-hydroxy-2-methylpyrimidine-4(3H)-one, and 6-hydroxy-2-ethylpyrimidine-4(3H)-one have two protonation stages, barbituric acid is protonated in three stages, and 6-hydroxy-2-methyl-5-nitropyrimidine-4(3H)-one and 6-hydroxy-2-ethyl-5-nitropyrimidine-4(3H)-one form a monocation.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic Study of the Basicity of 4,6-Dihydroxypyrimidine Derivatives

Yudin

Kushtaev

et al. 2021

ACS Omega

View full text Add to dashboard Cite

show abstract

“…Soon after acquiring habilitation, he focused his attention on studies of the spectroscopic properties of those molecular systems for which the phenomenon of tautomerism occurs, and since then he became interested in the tautomerism problem throughout his later career. First of all, he performed at that time self consistent field molecular orbital configuration interaction (SCF MO CI) calculations for N‐heterocyclic compounds substituted by the NH 2 group 9, derivatives of pyrazines 10, pyrimidines 11, pyridinealdoximes, and acetamidopyridines 12.…”

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confidence: 99%