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Статьи с участием сотрудников и пользователей РЦ

1) Applied Magnetic Resonance 2014

M. Popova, D. Michel

«Behavior of Sodium Lauroyl Sarcosinate in Solution and Binary Mixtures by Means NMR»

Applied Magnetic Resonance 2014, 45, 353-364

DOI 10.1007/s00723-014-0531-9

Measurements of the 1H and 13C chemical shifts as well as 1H spin–lattice relaxation times of sodium lauroyl sarcosinate (SLAS) in aqueous solutions and mixed binary systems with co-surfactants were carried out at various concentrations. It will be shown that changes in the chemical shifts for the N–CH2 groups in SLAS with increasing surfactant concentration can be used to estimate the ratio pcis /ptrans of cis- and trans-isomers. The relative fraction p trans of molecules in trans-configurations increases the most in a narrow concentration range 0.007–0.034 mol/l, i.e., at the transition from the monomeric state to the micelle. The ratio pcis /ptrans asymptotically decreases with increasing concentration, reaching a constant value at concentrations significantly above the critical micelle concentration. Thus, the ratio can be related to the process of micellization. If micellization takes place, the cis-isomer starts to transform into trans-isomer because the trans-isomer is more favorable in micelles. Because of the smaller cross section of the polar group region, the trans-conformation can be more easily incorporated into the micelle. In summary, the occurrence of micellar aggregates at low SLAS concentration in mixed systems can be clearly inferred from the nuclear magnetic resonance spectra.

2) Eur. J. Org. Chem. 2014

P. R. Golubev, A. S. Pankova, M. A. Kuznetsov

“Transition-Metal-Free Approach to 4-Ethynylpyrimidines via Alkenynones”

Eur. J. Org. Chem. 2014, 3614-3621

DOI: 10.1002/ejoc.201402045

A practical approach to the synthesis of 4-ethynylpyrimidines by the condensation of arylamidines with 2-aryl-1-ethoxy-5-(trimethylsilyl)pent-1-en-4-yn-3-ones has been developed. As these latter ketones are easily accessible from bis(trimethylsilyl)acetylene and arylacetyl chlorides, the regioselective condensation reported herein provides a facile access to both TMS-protected and unprotected 4-ethynylpyrimidines in yields of up to 85%.

3) Tetrahedron Lett. 2014

J. Malinina, T.Q. Tran, A.V. Stepakov, V.V. Gurzhiy, G.L. Starova, R.R. Kostikov, A.P. Molchanov

«[3+2] Cycloaddition reactions of arylallenes with C-(N-arylcarbamoyl)- and C,C-bis(methoxycarbonyl)nitrones and subsequent rearrangements»

Tetrahedron Lett. 2014, 55, 3663-3666

DOI: 10.1016/j.tetlet.2014.04.107

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The first example of 1,3-dipolar cycloaddition reactions of nitrones with arylallenes is described. C-Carbamoylnitrones react with the C1single bondC2 double bond of arylallenes affording the corresponding 4-methyleneisoxazolidines in good yields. N-Aryl-C,C-bis(methoxycarbonyl)nitrones usually gave rearranged products: mixtures of 4,5-dihydro-4-oxo-1H-benzo[b]azepine-2,2(3H)dicarboxylates and 4-oxo-1,5-diarylpyrrolidine-2,2-dicarboxylates.

4) Chem. Hetercycl. Compd. 2014

V.V. Sokolov, A.Yu. Ivanov, M.S. Avdontseva, A.A. Zolotarev

«Stereochemistry and NMR Spectra of Some Tricyclic Condensed Thiazolidine Derivatives with a Bridgehead Nitrogen Atom»

Chem. Hetercycl. Compd. 2014, 50, 550-556

DOI: 10.1007/s10593-014-1506-3

The configuration of a series of tricyclic condensed thiazolidines with a bridgehead nitrogen atom, for which erroneous data had been published, was determined by X-ray structural analysis and NMR spectroscopy.

5) Chem. Commun. 2014

V.A. Rassadin, E. Nicolas, Y. Six

«Ti(OiPr)4/nBuLi: an attractive reagent system for [2+2+2] cyclotrimerisation reactions»

Chem. Commun. 2014, Advance Article

DOI: 10.1039/C4CC02698E

A convenient method for the [2+2+2] cyclotrimerisation of alkynes using Ti(OiPr)4/nBuLi is presented. Homotrimerisation of arylacetylenes proceeds within minutes with excellent regioselectivity. Moreover, the intermolecular construction of ABB heterotrimers can be achieved selectively from two different alkynes with similar electronic properties. The method is also suitable for the synthesis of pyridines.