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Mamleev, A. Kh.; Gunderova, L. N.; Galeev, R. V.; Shapkin, A. A.

doi:10.1023/a:1022812921496

Cited by 4 publications

(4 citation statements)

References 9 publications

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“…In particular the great possibilities should be mentioned of the industrial application of cyclic acetals in the production of isoprene, 1,3-diols, and a number of drugs [1], and also in the synthesis of other six-membered 1,3,2-heterocyclic compounds [8], aminoalcohols and their derivatives [9]. The microwave spectroscopic studies established the geometrical characteristics of the most stable conformers of 2-methyl- [10], 4-methyl- [11], and 5-methyl-1,3-dioxanes [12]. The recent stereochemical studies actively utilized the quantum-chemical methods.…”

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confidence: 99%

Comparative conformational analysis of 1,3-dioxane and 1,3-dithiane

Кузнецов

2010

Russ J Org Chem

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It was shown by ab initio quantum-chemical approximations HF/6-31G(d) and MP2/6-31G(d)// HF/6-31G(d) that the conformational isomerization of 1,3-dioxane and 1,3-dithiane proceeded along common routes. The potential energy surface of both compounds contains six minima including the chair invertomers and enantiomeric fl exible forms. They are separated by several potential barriers. It was established by molecular dynamics method that the fl exible conformers at heating and keeping at 295-300 K transformed into each other and in the chair conformer.The interest to the structural investigation of 1,3-dioxanes and 1,3-dithianes originates from the features of their structure, their application in the industrial and fi ne organic synthesis, and also their promising physiologically active properties [1][2][3][4][5][6][7][8][9]. In particular the great possibilities should be mentioned of the industrial application of cyclic acetals in the production of isoprene, 1,3-diols, and a number of drugs [1], and also in the synthesis of other six-membered 1,3,2-heterocyclic compounds [8], aminoalcohols and their derivatives [9]. The microwave spectroscopic studies established the geometrical characteristics of the most stable conformers of 2-methyl-[10], 4-methyl- [11], and 5-methyl-1,3-dioxanes [12]. The recent stereochemical studies actively utilized the quantum-chemical methods. Thus in the framework of nonempirical approximations the minima on the potential energy suface (PES) were thoroughly studied for 1,3-dioxane [13] and 1,3-dithiane [14]. In the latter study also some transition states were investigated on the route of the conformational isomerization chairtwist and twist-twist. However up till now the general picture of the conformational transformations of the studied heterocyclic systems is absent in the literature. We formerly by the computer simulation established the main routes of the conformational isomerization both of the proper 1,3-dioxane [15] and its 2-methyl [16], 4-methyl [17], 4-phenyl [18], 4-trifl uoro methyl [19], 5-methyl [20], 5-isopropyl [21], and 2,5-dimethyl analogs [22]. This study concerns the comparative characteristic of the conformational isomerization of the molecules 1,3-dioxane (I) and 1,3-dithiane (II) by the use of ab initio approximations HF/6-31G(d) and МР2/6-31G(d)// HF/6-31G(d) calculated with HyperChem software [23]. O O I S S II According to 1 Н NMR data the molecules of the studied compounds at the room temperature undergo fast interconversion of the ring [2, 3, 24]. X X X X C inv CWe established that the PES of formals (I) and (II) contained six minima: invertomers of the chair and of fl exible forms. The routes of the conformational isomerization chair-chair (C-C inv) are identical in both compounds and suggest the interconversions by four independent routes through the conformers of flexible forms 2,5-twist-(2,5-Т) and 1,4-twist (1,4-Т). The

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confidence: 99%

Comparative conformational analysis of 1,3-dioxane and 1,3-dithiane

Кузнецов

2010

Russ J Org Chem

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“…The pseudorotation of 1,3-dioxolane has been already studied by some authors. For what concerns experimental studies, results obtained from an electron diffraction investigation and from microwave − and far-infrared , spectra are available in the literature. The calculation of the 2D-PES has been performed and published by Cremer et al , …”

Section: Computational Results: 2d-pes Calculationsmentioning

confidence: 99%

Potential-Energy Surfaces for Ring-Puckering Motions of Flexible Cyclic Molecules through Cremer–Pople Coordinates: Computation, Analysis, and Fitting

Paoloni

Rampino

Barone

2019

J. Chem. Theory Comput.

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Ring-puckering motion in 12 flexible cyclic molecules is investigated by calculation and analysis of two-dimensional potential-energy surfaces (PESs) using the so-called ring-puckering coordinates proposed by Cremer and Pople. The PESs are calculated by means of density-functional theory using a B2PLYP-D3BJ exchange− correlation functional with a maug-cc-pVTZ basis set, and results are compared to the available experimental and theoretical data. Special care is devoted to the aspect of symmetry in such two-dimensional PESs, which are here reported for the first time also for molecules whose planar form has symmetry lower than D 5h or C 2v . The issue of PES fitting and that of solving the nuclear dynamics using ring-puckering coordinates are also addressed. Analytical formulations of the computed PESs using suitable functional forms with a limited set of parameters are provided.

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“…Some limitations of the model employed in this work can be readily identified taking into account the alternative approaches mentioned in the Introduction. When the computed potential energy barriers are extremely small (which is not the case of the molecules investigated in this work), SAMs can affect the final results of the 1D problem even qualitatively (in the case of 1,3-dioxolane molecule this aspect was taken into account in ref ; see refs and for a comparison with experimental results). In this case, the effects of SAMs on the calculated solutions of the nuclear problem cannot be safely neglected.…”

Section: Accuracy Limitations and Possible Improvements Of The Modelmentioning

confidence: 97%

Interplay of Rotational and Pseudorotational Motions in Flexible Cyclic Molecules

Paoloni

Maris

2021

J. Phys. Chem. A

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Solutions to the time-independent nuclear Schrödinger equation associated with the pseudorotational motion of three flexible cyclic molecules are presented and discussed. Structural relaxations related to the pseudorotational motion are described as functions of a pseudorotation angle ϕ which is formulated according to the definition of ring-puckering coordinates originally proposed by Cremer and Pople ( J. Am. Chem. Soc. 1975 97 1354 1358 ). In order to take into account the interplay between pseudorotational and rotational motions, the rovibrational Hamiltonian matrices are formulated for the rotational quantum numbers J = 0 and J = 1. The rovibrational Hamiltonian matrices are constructed and diagonalized using a Python program developed by the authors. Suitable algorithms for (i) the construction of one-dimensional cuts of potential energy surfaces along the pseudorotation angle ϕ and (ii) the assignment of the vibrorotational wave functions (which are needed for the automatic calculation of rotational transition energies J = 0 → J = 1) are described and discussed.

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Cited by 4 publications

References 9 publications

Comparative conformational analysis of 1,3-dioxane and 1,3-dithiane

Comparative conformational analysis of 1,3-dioxane and 1,3-dithiane

Potential-Energy Surfaces for Ring-Puckering Motions of Flexible Cyclic Molecules through Cremer–Pople Coordinates: Computation, Analysis, and Fitting

Interplay of Rotational and Pseudorotational Motions in Flexible Cyclic Molecules

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