Theoretical studies of the tautomerism in oxazolidine and thiazolidine heterocyclic systems

Tahmassebi, Daryoush

doi:10.1016/s0166-1280(03)00239-2

Cited by 29 publications

(18 citation statements)

References 20 publications

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“…The calculations predict that the oxo/thione form (R1) is 5.2 kcal mol -1 more stable than the oxo/thiol form R4. These results are in agreement with the previous results, [5][6][7][8]27,28 The protonated and deprotonated oxo/ thione forms P2b and D1 are thermodynamically more stable than the protonated and deprotonated oxo/thiol forms P4a and D3 by 2.5 and 4.6 kcal mol Our results show that the neutral oxo/thiol forms R4 and R5 are more stable other neutral enol/thione and enol/thiol forms; implying that the hydrogen atom during the 1,3-H transfer process prefers to migrate to heteroatom of the thiocarbonyl group (C2=S7) than that of the other heteroatom of the carbonyl group (C2=O6). These results can be explained in terms of the higher polarizability and consequently the size of the sulfur atom than of the oxygen atom.…”

Section: Relative Stabilitysupporting

confidence: 94%

“…Of particular interest is their ability to donate electrons toward metal ions, which makes them suitable as ligands in the complexation reaction for use in analytical chemistry as sensitive reagents for the analysis of heavy metals 3,4 . Recently, tautomerization of rhodanine family have been theoretically and experimentally studied [5][6][7][8] . These studies suggested that the dioxo, dithione, oxo/thione and thione/oxo derivatives are the predominant form.…”

Section: Introductionmentioning

confidence: 99%

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Tautomeric Study of Neutral, Protonated and Deprotonated Isorhodanine Based on High Level Density Functional Theory

Safi¹

2016

Orient. J. Chem

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High level Density Functional Theory (DFT) using B3LYP/6-311++G(2df,2p)//6-311+G(d,p) calculations on the relative stabilities and structures of the neutral, protonated and deprotonated isorhodanine tautomeric forms are reported in the gas phase and solution. Gas phase and solution B3LYP calculations predict that the oxo/thione tautomer is the most stable one in all cases. Comparison of the gas phase results, bond lengths, bond angles and relative energies, with those of the solution reveals very strong linear relationships. Results of the calculated proton affinities (PAs), molecular gas phase basicity (GBs) and deprotonation enthalpies (DH dep ) indicate that isorhodanine behaves as a sulfur base. The isomerization processes leading from the most stable species to the less stable ones are also investigated.

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Section: Relative Stabilitysupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Tautomeric Study of Neutral, Protonated and Deprotonated Isorhodanine Based on High Level Density Functional Theory

Safi¹

2016

Orient. J. Chem

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“…Also, understanding of the relative stabilities of heterocyclic tautomers and any subsequent conversions between tautomeric forms is very vital for both structural chemists and biologists 1,2 . Along this line, relative stabilities of various tautomeric structures of five-, six-and sevenmembered ring (dioxo, oxo/thio, oxo/seleno, dithio and diseleno combinations) were investigated using both theoretical and experimental tools [3][4][5][6][7][8][9][10][11][12] …”

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confidence: 99%

Theoretical Investigation of Tautomerism Stability of Hydantoin in the Gas Phase and in the Solution

Fares¹,

Safi²

2014

Orient. J. Chem

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Intramolecular 1,3-proton transfer of the keto-enol reactions of heterocyclic systems with several basic centers, O, N, S and Se atoms, are of great interest to medicinal and biochemical applications. Also, understanding of the relative stabilities of heterocyclic tautomers and any subsequent conversions between tautomeric forms is very vital for both structural chemists and biologists 1,2 . Along this line, relative stabilities of various tautomeric structures of five-, six-and sevenmembered ring (dioxo, oxo/thio, oxo/seleno, dithio and diseleno combinations) were investigated using both theoretical and experimental tools [3][4][5][6][7][8][9][10][11][12] ABSTRACTThe relative stability of the different tautomers of hydantoin has been studied through the use of DFT method. The structures and the vibrational frequencies of all stable tautomers and all the transitions states connecting between them have been calculated at the B3LYP/6-311+G(d,p) level of theory in the gas phase and selected solvents using IE-PCM model. Final energies have been obtained in single-point B3LYP/6-311++(3df,2p) calculations. The results show that the diketo tautomer T1 is more stable than the other tautomers. Variation of charge densities at bond critical points, dipole moments and NBO charges on atoms in the solvents were studied.

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“…The rhodanine group in dye compositions acts as an electron density acceptor. Rhodanine also forms strong colored coordination compounds with many heavy metal ions such as Pd 2+ , Pt 2+ [8], Ag + , Au + [9], Cu + [10], Ni 2+ , Co 2+ [11], Cu 2+ , Hg 2+ , Au 3+ , and Ru 3+ [12] what is used for their spectrophotometric determination.Rhodanine may exist in ketone, enol, and thioenol tautomeric forms [13][14][15][16][17] due to the presence of ketone and thioketone functional groups in a molecule and an active hydrogen atom of the NH bond (with dissociation constant K d = 10 -8 in water [13,14]). The enol and thioenol tautomers can each form two rotamers, while a total of eleven tautomers and rotamers exist taking account of the possible dissociation of rhodanine at the methylene group CH bond [17].…”

mentioning

confidence: 99%

Theoretical study of the dimerization of rhodanine in various tautomeric forms

Baryshnikov

Минаев

Минаева

et al. 2012

Chem Heterocycl Comp

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The density functional theory (DFT) was used to calculate the relative stability of rhodanine dimers and the energy of intermolecular interaction in them. Analysis of the electron density showed hydrogen bonding in the dimers. The energies of individual hydrogen bonds were determined for the symmetrical dimers. The polarizable continuum model was used to calculate the solvation (hydration) energies of the structures studied. The effect of dimerization on the position of infrared absorption bands was demonstrated.Rhodanine (2-thioxothiazolidin-4-one) and its derivatives, which are common reagents in analytical and coordination chemistry, attract special interest in medicine, biochemistry, and photochemistry. Rhodanine derivatives modified at the methylene group (ylidenerhodanines) possess antibacterial [1], antifungal [2-4], antidiabetic [5], and anticancer activity [6]. This accounts for the use of rhodanine in the pharmaceutical industry [5].Free rhodanine is used for the synthesis of indoline, triphenylamine, and phenothiazine sensitizing dyes for solar cells [7]. The rhodanine group in dye compositions acts as an electron density acceptor. Rhodanine also forms strong colored coordination compounds with many heavy metal ions such as Pd 2+ , Pt 2+ [8], Ag + , Au + [9], Cu + [10], Ni 2+ , Co 2+ [11], Cu 2+ , Hg 2+ , Au 3+ , and Ru 3+ [12] what is used for their spectrophotometric determination.Rhodanine may exist in ketone, enol, and thioenol tautomeric forms [13][14][15][16][17] due to the presence of ketone and thioketone functional groups in a molecule and an active hydrogen atom of the NH bond (with dissociation constant K d = 10 -8 in water [13,14]). The enol and thioenol tautomers can each form two rotamers, while a total of eleven tautomers and rotamers exist taking account of the possible dissociation of rhodanine at the methylene group CH bond [17]. Thus, we might expect the existence of a wide variety of dimeric complexes, which may be formed in crystals, solutions, and the gas phase.Loncharich et al. [13] have carried out an X-ray diffraction structural analysis and experimentally identified some of the dimers predicted in our earlier work. This offered the prospect of identifying other dimeric complexes.In the present work, we present the results of quantum-chemical modelling for various rhodanine dimers. These data contribute to a general understanding of the dimerization behavior and may be useful for developing the chemistry of rhodanines and ylidenerhodanines as well as for methods of infrared spectral

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Theoretical studies of the tautomerism in oxazolidine and thiazolidine heterocyclic systems

Cited by 29 publications

References 20 publications

Tautomeric Study of Neutral, Protonated and Deprotonated Isorhodanine Based on High Level Density Functional Theory

Tautomeric Study of Neutral, Protonated and Deprotonated Isorhodanine Based on High Level Density Functional Theory

Theoretical Investigation of Tautomerism Stability of Hydantoin in the Gas Phase and in the Solution

Theoretical study of the dimerization of rhodanine in various tautomeric forms

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