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91.
Jinesh M. Kuthanapillil A. Nijamudheen Nayana Joseph Praveen Prakash E. Suresh Ayan Datta K.V. Radhakrishnan 《Tetrahedron》2013
A detailed investigation on the effect of solvent polarity, temperature, and microwave irradiation on periselectivity in cycloaddition reactions of pentafulvenes with 3-oxidopyrylium betaine is described. The base catalyzed generation of 3-oxidopyrylium betaine in CHCl3 resulted in the exclusive formation of [6+3] adducts. With increase in solvent polarity and temperature, mixtures of [6+3] and [3+2] adducts were formed, where as under microwave irradiation, [3+2] adducts were formed exclusively. The experimental results have been rationalized on the basis of theoretical calculations. 相似文献
92.
Synthesis,spectroscopic evaluation,molecular modelling,thermal study and biological evaluation of manganese(II) complexes derived from bidentate N,O and N,S donor Schiff base ligands
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Manganese(II) complexes having the general composition Mn(L)2X2 (where L = 3‐bromoacetophenone semicarbazone, 3‐bromoacetophenone thiosemicarbazone, 1‐tetralone semicarbazone, 1‐tetralone thiosemicarbazone, flavanone semicarbazone or flavanone thiosemicarbazone and X = Cl? or ½SO42?) were synthesized. All the complexes were characterized using elemental analyses, molar conductance and magnetic moment measurements, and mass, 1H NMR, infrared, electron paramagnetic resonance and electronic spectral studies. The molar conductance of the complexes in dimethylsulfoxide lies in the range 10–20 Ω?1 cm2 mol?1 indicating their non‐electrolytic nature. All the complexes show magnetic moments corresponding to five unpaired electrons. The possible geometries of the complexes were assigned on the basis of electron paramagnetic resonance, electronic and infrared spectral studies. Some of the synthesized ligands and their complexes were screened for their antifungal activities against fungi Macrophomina phaseolina, Botrytis cinerea and Phoma glomerata using the food poison technique and their antibacterial activities against Xanthomonas campestris pv. campestris and Ralstonia solanacearum using the paper disc diffusion method. They showed appreciable activities. 相似文献
93.
Vicinal proton couplings in cyclopropane have been calculated using Dirac-Van Vleck and variational methods in valence bond formalism. The couplings may be considered as taking place along a path comprising either three or four intervening bonds. Inclusion of all exchange integrals in the appropriate fragment models leads to a satisfactory ratio of Jcis/Jtrans . In this respect valence bond results appear to be superior to those obtained using a molecular orbital approach. The present valence bond results on couplings in cyclopropane are not affected by the choice of models for bonding in cyclopropane, namely the Coulson-Moffitt model or the Walsh model. 相似文献
94.
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96.
Condensation of uracil derivatives (1,3,4) with acetone in the presence of triethylamine gave pyranopyrimidines (2,5,6). 相似文献
97.
B. H. Doreswamy Chandra K. Mantelingu M. A. Sridhar M. Mahendra 《Research on Chemical Intermediates》2014,40(8):2659-2665
The isolation of stable carbenes of the Arduengo and Wanzlick type has prompted us to look for stable nitrenium ions of the related structural type 1-Hydroxy-3-methyl benzotriazolium trifluromethane sulfonate. Nitrenium ions are azocations with structure and survive long enough under in vitro conditions to bind with biological nucleophiles, i.e. DNA bases, and play an important role in carcinogenic processes involving the metabolism of aromatic amines. The title compound (C15H16F3N6O5S) was isolated and crystallized in the monoclinic space group Cc with cell parameters a = 19.866(1) Å, b = 13.128(9) Å, c = 7.673(5) Å, and Z = 4. The structure has both intra- and intermolecular hydrogen bonds. 相似文献
98.
G.K. Surya Prakash Laxman Gurung Philipp Christoph SchmidFang Wang Tisa Elizabeth ThomasChiradeep Panja Thomas MathewGeorge A. Olah 《Tetrahedron letters》2014
Nitroso compounds are versatile reagents in synthetic organic chemistry. Herein, we disclose a feasible protocol for the ipso-nitrosation of aryl boronic acids using chlorotrimethylsilane–sodium nitrite unison as nitrosation reagent system. 相似文献
99.
100.
Samadhan S. Nagane Sachin S. Kuhire Uday A. Jadhav Sushilkumar A. Dhanmane Prakash P. Wadgaonkar 《Journal of polymer science. Part A, Polymer chemistry》2019,57(5):630-640
A bisphenol bearing pendant maleimide group, namely, N‐maleimidoethyl‐3, 3‐bis(4‐hydroxyphenyl)‐1‐isobenzopyrrolidone (PPH‐MA) was synthesized starting from phenolphthalein. Aromatic (co)polyesters bearing pendant maleimide groups were synthesized from PPH‐MA and aromatic diacid chlorides, namely, isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), and 50:50 mol % mixture of IPC and TPC by low temperature solution polycondensation technique. Copolyesters were also synthesized by polycondensation of different molar proportions of PPH‐MA and bisphenol A with IPC. Inherent viscosities and number‐average molecular weights of aromatic (co)polyesters were in the range of 0.52–0.97 dL/g and 20,200–32,800 g/mol, respectively indicating formation of medium to reasonably high‐molecular‐weight polymers. 13C NMR spectral analysis of copolyesters revealed the formation of random copolymers. The 10% weight loss temperature of (co)polyesters was found in the range 470–484 °C, indicating their good thermal stability. A selected aromatic polyester bearing pendant maleimide groups was chemically modified via thiol‐maleimide Michael addition reaction with two representative thiol compounds, namely, 4‐chlorothiophenol and 1‐adamantanethiol to yield post‐modified polymers in a quantitative manner. Additionally, it was demonstrated that polyester containing pendant maleimide groups could be used to form insoluble crosslinked gel in the presence of a multifunctional thiol crosslinker. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 630–640 相似文献