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141.
In a convenient one-pot sequence, treatment of bezoin and p-anisoin oximes with sodium hydride in dry THF in 1:2 molar ratio generates 1,5-dianion, which upon subsequent addition of diorganodichlorosilane yields 1,3,4,2-dioxazasilacyclohexene derivatives in good yields. In general, very often a salt elimination route is used for the synthesis of the title compounds. 相似文献
142.
The lithium enolate of (+)-camphor reacts with sulfur dioxide and 3-methyl-2-butenyl bromide to produce the β-keto-sulfone 3-(endo)-[3′-methyl-2′-butenyl-sulfonyl]-camphor 4. 相似文献
143.
Oxidation of chromanones (1a-i) and 2-spiro-chromanones (j-m) using [hydroxy(tosyloxy)iodo] benzene in refluxing acetonitrile as well as using ultrasound via dehydrogenation and 2,3-alkyl migration provides a convenient route for the synthesis of chromones (2a-i), tetrahydroxanthones (2j,k) and their higher homologues (21,m). The ultrasound also enhances substantially the rate of above transformations. 相似文献
144.
Reaction of aldoximes with iodobenzene dichloride leads to formation of corresponding nitrile oxides in good yields in a single pot reaction. 相似文献
145.
A simple, efficient, and diastereoselective synthesis of 5-methylene-dihydropyran-2,6-diones and 3-methylene-3,4-dihydropyran-2-ones from substrates afforded by the SN2 reaction between the acetyl derivatives of the Baylis–Hillman adducts and methylacetoacetate or acetylacetone or benzoyl acetone via saponification followed by P2O5-mediated cyclization is described. 相似文献
146.
Krishna Nand Singh 《合成通讯》2013,43(16):2651-2654
A safe and simple method of preparing organic carbamates has been achieved from amines and carbon dioxide using tetraethylammonium superoxide generated in situ. 相似文献
147.
Vinyl sulphides find a substantial application in organic synthesis.2 The synthetic utility of heter cyclic vinyl sulphides due to the ease in extension of heterocyclic ring3 should be more versatile, Here, we report the synthesis of isoquinolinyl vinyl sulphides from dihydrothiazolo [2, 3-a] isoquinolinium cations, depicting another use of heterocycles in organic synthesis.4 相似文献
148.
Mandeep Singh Bakshi 《Journal of Dispersion Science and Technology》2013,34(5):615-631
The conductances of sodium perfluorooctanoate (SPFO), sodium dodecylsulphate (SDS), dodecyltrimethylammonium bromide (DTAB), and tetradecyltrimethylammonium bromide (TTAB) in 18-crown-6 ether + water (CR+W), p-cyclodextrin + water (CY+W), and 1,10-phenanthroIine + water (Phen+W) mixtures with fixed 4 mM of each additive were determined over the temperature range of 5-55 °C. The conductivity plots for all the surfactants showed single break from which the critical micellization concentration (cmc) and degree of micelle ionization (x) were computed. From the pre and the post micellar slopes of the conductivity curves, the equivalent conductivities of the monomeric (Aass) and the micellar states (Amjc), respectively, were calculated and discussed with respect to the surfactant-additive complexation. It was observed that the micelle formation of all the ionic surfactants irrespective of the nature of their head groups were delayed in CYC+W in comparison to that in CR+W and Phen+W systems over the temperature range studied. The micelle formation of SPFO and SDS in CR+W and Phen+W systems showed stabilization of the respective micelles due to the adsorption of Na+-CR and Na+-Phen complexes at the micelle solution interface in comparison to that of DTAB and TTAB. 相似文献
149.
Rinki Bhadra Vidya Nand Singh Bodh Raj Mehta Pranayee Datta 《Journal of Dispersion Science and Technology》2013,34(9):1202-1207
ZnO nanocrystals are synthesized using the quenching method. The properties of the grown nanocrystals are studied using ultraviolet-vis spectroscopy, x-ray diffraction, photoluminescence, electron diffraction, energy dispersive x-ray spectroscopy, and high resolution transmission electron microscopy. Current-voltage characteristics of the prepared samples are studied for investigating the possible application of the samples as switch and memristor. 相似文献
150.
Yokraj Katre Minu Singh Ajaya Kumar Singh 《Journal of Dispersion Science and Technology》2013,34(6):903-912
The kinetics and mechanism of N-bromosuccinimide (NBS) oxidation of D-mannose in the absence and presence of cetyltrimethylammonium bromide (CTAB) in acidic media have been studied under the condition [D-mannose]T ? [NBS]T at 40°C. Under the kinetic conditions, both the slower uncatalyzed and faster catalyzed paths go on. Both the paths show the fractional and first order dependence on [D-mannose] and [NBS]T, respectively. The rate decreased with increase in acidity. Neither succinimide (NHS) nor Hg(II) influenced the reaction rate. Activation parameters of the reactions were determined by studying the reaction at different temperatures (30–50°C). The influence of salts on the reaction rate was also studied. CTAB accelerates the reactions and the observed effects have been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. In the reaction, approximately 1 mole of NBS oxidized one mole of D-mannose. A reaction scheme of the oxidation of D-mannose by NBS was found to be in consistent with the rate law and the reaction stoichiometry. 相似文献