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11.
Khafizova L. O. Ibragimov A. G. Yalalova D. F. Borisova A. L. Khalilov L. M. Dzhemilev U. M. 《Russian Chemical Bulletin》2003,52(9):2012-2016
A method for the synthesis of secondary and tertiary alcohols was developed. The method is based on cycloalumination of olefins with trialkylalanes in the presence of Zr-containing catalysts followed by the CuCl-catalyzed in situ reaction of the corresponding aluminacyclopentanes with aldehydes or ketones. 相似文献
12.
[formula: see text] The appended sugars in macrolide antibiotics are indispensable to the biological activities of these important drugs. In an effort to generate a set of novel macrolide derivatives, we have created a new analogue of methymycin and neomethymycin, antibiotics produced by Streptomyces venezuelae. This analogue 15 carrying a different sugar, D-quinovose, instead of D-desosamine, was constructed by taking advantage of targeted gene deletion combined with a specific pathway-independent C-3 reduction capability of the wild type S. venezuelae. 相似文献
13.
Sessler JL Roznyatovskiy V Pantos GD Borisova NE Reshetova MD Lynch VM Khrustalev VN Ustynyuk YA 《Organic letters》2005,7(23):5277-5280
[reaction: see text] Two easy-to-synthesize polypyrrolic 2,5-diamidothiophene Schiff base macrocycles are reported, along with their anion binding properties as determined via UV-vis spectroscopic titrations carried out in dichloroethane. There is a striking difference between the interactions with anions of the two macrocycles, a finding ascribed to differences in their rigidity. For example, the more flexible dipyrromethane-derived macrocycle displays a 1.2:1 hydrogen sulfate versus nitrate selectivity, while its more rigid bipyrrole-derived congener shows a 7.4:1 selectivity in favor to hydrogen sulfate. 相似文献
14.
A sensitive method of Co(II) determination by adsorptive stripping voltammetry is presented. The method exploits the enhancement of cobalt peak current observed in the system Co(II)-nioxime-cetyltrimethylammonium bromide-piperazine-N,N′-bis(2-ethanesulfonic acid). The calibration plot for an accumulation time of 60 s is linear from 5 × 10−11 to 3 × 10−9 mol L−1. The relative standard deviation is 3.8% for Co(II) determination at concentration 1 × 10−9 mol L−1. The detection limit is 1.7 × 10−11 mol L−1. The validation of the method is performed by the analyses of certified reference materials and comparing the result of Co(II) determination in river water sample by the proposed method with those obtained by ET AAS. The main advantage of this new system is the micro-trace Co(II) determination by adsorptive stripping voltammetry, as compared to those described before, a low concentration of the supporting electrolyte used, and so commercially available reagents without additional purification can be used. 相似文献
15.
A. V. Borisov V. K. Belsky V. K. Osmanov G. N. Borisova Zh. V. Matsulevich 《Chemistry of Heterocyclic Compounds》2006,42(10):1346-1351
Reaction of perfluoro-1-ethyl-2-methyl-1-propenyliminochloromethanesulfenyl chloride with 1-allyl-2-methoxybenzene in methylene
chloride and nitromethane gives as the main products β-and β-chloro sulfides plus derivative of 2,3-dihydrobenzofuran. The
reaction in nitromethane in the presence of lithium perchlorate gave a product of addition of sulfur-containing electrophiles
to the double bond-a derivative of 1,3-thiazolidin-2-one-in preference to the cycloaddition product.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1558–1564, October, 2006. 相似文献
16.
N. S. Prostakov A. V. Varlamov T. N. Borisova 《Chemistry of Heterocyclic Compounds》1984,20(5):519-521
The catalytic dehydrocyclization of 3-isopropyl-2,6-diphenylpyridine proceeds in two directions: conversion to 10-methyl-3-phenyl-4-azaphenanthrene and conversion to 9,9-dimethyl-4-azafluorene. C(9)-Unsubstituted 4-azafluorenes were obtained in the dehydrocyclization of pyridine bases that contain a phenyl group in the position and an n-propyl group in the position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 648–650, May, 1984. 相似文献
17.
Wójcik A Naumov S Marciniak B Hermann R Brede O 《The journal of physical chemistry. B》2005,109(31):15135-15144
Addition and elimination interaction of thiyl radicals with the C5-C6 double bond in pyrimidines was studied by the pulse radiolysis technique in aqueous solution with the use of different monitoring systems. For this purpose, p-thiocresol, cysteamine hydrochloride, and mercaptoethanol were used. The rate constants of addition and elimination of thiyl radicals were determined by applying the modified version of ACUCHEM (computer program for modeling complex reaction systems). Aliphatic thiyl radicals add to the pyrimidine C5-C6 double bond with k = 1.0-3.0 x 10(7) dm3 mol(-1) s(-1), whereas elimination takes place with k = 0.7-2.0 x 10(5) s(-1). Quantum chemical calculations at the B3LYP/6-31G(d)/PCM level show that the addition should occur at the C6 position of the pyrimidine ring and that the energy of interaction between thiyl radicals and the pyrimidine double bond C5-C6 is low. 相似文献
18.
M. V. Koroleva L. V. Borisova A. K. Chibisov 《Theoretical and Experimental Chemistry》1987,23(3):339-342
Photoreduction reactions of Re(VII) in the presence of an electron donor — diphenylamine (DPA) and hydroquinone (HQ) in concentrated hydrochloric acid solutions — were studied using the pulse photolysis method. The short-lived complex of rhenium(VI) ReOCL5 undergoes one-electron oxidation reactions with both DPA to form a cation-radical DPA+. and with HQ to form a semiquinone radical. The decay of the cation-radicals DPA+. proceeds by a second order reaction with the formation of a stable product (max=590 nm)Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 3, pp. 365–368, May–June, 1987. 相似文献
19.
Sek S Tolak A Misicka A Palys B Bilewicz R 《The journal of physical chemistry. B》2005,109(39):18433-18438
Polyalanine derivatives containing cysteamine linker R-(Ala)14NH-(CH2)2-SH, where R is ferrocenecarbonyl or hydrogen, were synthesized and then used to form self-assembled monolayers on gold. The tilt angles and the packing density of the molecules within monolayer assemblies were determined by FTIR spectroscopy and scanning tunneling microscopy, respectively. Electrochemical properties of monolayer-modified electrodes were studied using cyclic voltammetry and impedance spectroscopy. Measurements of electron-transfer rates using electrochemical techniques and scanning tunneling spectroscopy revealed asymmetry dependent on the applied voltage. It is suggested that the observed electron-transfer behavior is connected with the electric field generated by the molecular dipole of the polyalanine helix. 相似文献
20.
L. G. Voskressensky T. N. Borisova L. N. Kulikova A. V. Varlamov 《Chemistry of Heterocyclic Compounds》2007,43(7):913-918
The interaction of 7-trifluoroacetyltetrahydropyrrolo[1,2-c]pyrimidine with acetylenedicarboxylic ester (DMAD) and ethyl propiolate
in acetonitrile and alcohols has been studied. It was established that DMAD splits pyrrolopyrimidine at the aminal fragment
in acetonitrile and methanol with the formation of 1-H-and 2-(N-dimethoxycarbonylvinyl-N-methyl)aminoethyl-1-methoxymethyl-3-methyl-5-trifluoroacetylpyrroles.
In acetonitrile ethyl propiolate splits pyrrolopyrimidine both at the aminal fragment and at the C(3)-N(2) bond (Hofmann reaction), but in ethanol only at the C(3)-N(2) bond with the formation of 2-propenylpyrroles.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1082–1087, July, 2007. 相似文献