ChemInform Abstract: HETERO‐AROMATIC CATIONS PART 18, PK(R)+ AND NMR‐SPECTRA OF SOME 2‐, 3‐ AND 4‐ARYLDERIVATIVES OF 1‐THIANAPHTHALENIUM PERCHLORATE

Degani, Iacopo; Fochi, Rita; Spunta, Giuseppe

doi:10.1002/chin.197445102

Cited by 10 publications

(20 citation statements)

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“…Table 2 gives the calculated values of the hydride ion, hydrogen atom, and proton affinities and also the ionization potentials of the named molecular systems. The results of the calculations show that the experimental "hydride" mobility series S > O ≈ Se [47][48][49] does not contradict the ionization potentials (IP) of molecules 1-6 or the hydrogen atom affinity (HAA) of the radicals formed by removal of the hydrogen atom at position 4 of the heterocycle from the initial systems 1-6.…”

Section: Subjects Of Investigationmentioning

confidence: 94%

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Quantum-Chemical Study of “Hydride” Mobility in the Molecules of Chalcogenopyrans

Pankratov

Drevko

2005

Chem Heterocycl Compd

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An approach is proposed for the quantum-chemical investigation of "hydride ion" transfer based on analysis of the similarity of the order of variation in the ionization potentials, enthalpies, and free energies of affinity to the hydride ion, the hydrogen atom, and the proton in the substrate molecules and also the derivatives of their cations, radicals, and ions to the experimentally established "hydride" series. It was established that the experimental "hydride" mobility series of six chalcogenopyrans based on "semicyclic" 1,5-diketones agrees with the quantum-chemically calculated ionization potentials of the molecules and with the affinity of the respective radicals to the hydrogen atom participating in the transfer. It was found that direct removal of a hydride ion and initial deprotonation of the substrates followed by the removal of two electrons are unlikely. "Hydride" shift mechanisms, in which the first stage is transfer of an electron or hydrogen atom from the chalcogenopyran molecules, are feasible.Reactions including stages that can formally be represented as hydride-ion transfer are of great significance in chemistry [1]. Examples include the transformations of 1,5-dicarbonyl compounds and chalcogenopyrans in a mixture of chalcogenopyrylium salts and chalcogenocyclohexanes or chalcogenopyrylium salts and other reduced products [2]. The following mechanisms of "hydride" transfer have been discussed for a wide range of chemical compounds [1]:1. Direct abstraction of a hydride ion (-H -). 2. Successive ejection of an electron, a proton, and another electron (-e -, -H + , -e -). 3. Removal of an electron and a hydrogen atom (-e -, -H · ). 4. Transfer of a hydrogen atom and an electron (-H · , -e -). 5. Deprotonation followed by the transfer of two electrons (-H + , -e -, -e -). The mechanism of the "minus electron, minus electron, minus proton" type (-e -, -e -, -H + ) should not be realized since the formation of the dication-radical is unlikely.However, in our opinion, there also exists a mechanism not examined in the present paper, involving initial protonation of the heterocycle and a final stage with release of H 2 [3] or another electrically neutral molecule [4]. The possible protonation of a heterocycle at a chalcogen atom was demonstrated conclusively in the papers of Lambert and others [5]. __________________________________________________________________________________________ 1 N.

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Section: Subjects Of Investigationmentioning

confidence: 94%

“…It was established as a result of the investigations [47,48], in which the "heteroaromatic cationchalcogenopyran" equilibrium was examined, and the construction of comparative reactivity series that thiopyrans are more liable to eliminate a "hydride ion" than the oxygen and selenium analogs. …”

Section: Subjects Of Investigationmentioning

confidence: 99%

Quantum-Chemical Study of “Hydride” Mobility in the Molecules of Chalcogenopyrans

Pankratov

Drevko

2005

Chem Heterocycl Compd

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“…Yield: 30%; mp 50-51°C (lit. 12 5.14. 10-Methoxy-6H- [1]benzothiopyrano [4,3-b]quinolin-9-ol (9a) Na (0.32 mol) was dissolved in 200 mL EtOH, followed by addition of compounds 4 (0.02 mol) and 7a (0.02 mol).…”

Section: -Methyl-34-dihydro-2h-1-benzothiopyran-4-one (7f)mentioning

confidence: 98%

Synthesis and in vitro anti-hepatitis B virus activity of 6H-[1]benzothiopyrano[4,3-b]quinolin-9-ols

Wei

Liu

et al. 2009

Bioorganic & Medicinal Chemistry

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“…Dans le cas du soufre, nous constatons que le rendement en thio-1 coumarine par oxydation par Mn02 [3] …”

Section: Oxydatiotz Des Produits D'hydrolyse Des Perchlorates De unclassified

“…[3] et d'examiner I'oxydation des produits d'hydrolyse des perchlorates de chromylium, thio et sklenochromylium. Dans le cas du sklenium, en particulier, nous allons voir s'il est possible d'eviter 1e retrecissement du cycle pour aboutir a des skleno-1 coumarines.…”

Section: Introductionunclassified

Oxydation sélective de thio‐1 et séléno‐1 chromènes. obtention de thio‐1 et séléno‐1 coumarines, de formyl‐2 benzo(b) thiophènes, de formyl‐2 benzo(b) sélénophènes et d'autres isomères

Ruwet¹,

Meessen²,

Renson³

1969

Bulletin des Soc Chimique

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A. RUWET, J. MEESSEN et M. RENSONThe thio-l and seleno-l coumarins are now obtained by cyclization of the appropriated cinnamic acids [l]. We find a second general method by the selective oxidation of thio-l and seleno-1 chromens 121. This reaction leads to several products but we find how to favour the formation of the wished compounds by the choice of the oxidant, of the solvent and of the temperature. We describe the ways giving good yields of thio-1 coumarins, seleno-1 coumarins, formyl-2 benzo(b) thiophenes, formyl-2 benzo(b) selenophenes and other substances.

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ChemInform Abstract: HETERO‐AROMATIC CATIONS PART 18, PK(R)+ AND NMR‐SPECTRA OF SOME 2‐, 3‐ AND 4‐ARYLDERIVATIVES OF 1‐THIANAPHTHALENIUM PERCHLORATE

Cited by 10 publications

References 0 publications

Quantum-Chemical Study of “Hydride” Mobility in the Molecules of Chalcogenopyrans

Quantum-Chemical Study of “Hydride” Mobility in the Molecules of Chalcogenopyrans

Synthesis and in vitro anti-hepatitis B virus activity of 6H-[1]benzothiopyrano[4,3-b]quinolin-9-ols

Oxydation sélective de thio‐1 et séléno‐1 chromènes. obtention de thio‐1 et séléno‐1 coumarines, de formyl‐2 benzo(b) thiophènes, de formyl‐2 benzo(b) sélénophènes et d'autres isomères

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