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1.
Polymers containing substituted 2-phenyl-benzoxazole side-chain groups: Synthesis and phase behavior
Roberto Centore Barbara Panunzi Antonio Roviello Augusto Sirigu Paola Villano 《Journal of polymer science. Part A, Polymer chemistry》1996,34(15):3203-3211
The synthesis of substituted 2-phenyl-benzoxazoles has been accomplished by ring closure of Schiff bases. The compounds have been used as precursors of acrylic derivatives displaying LC properties: Four comb-like homopolymers have been obtained by radical catalysis from the acrylic monomers. The polymers have been characterized by 1H-NMR, DSC, x-ray diffraction, viscometry, and polarizing microscopy. Three of the polymers exhibit liquid crystalline properties of smectic type. © 1996 John Wiley & Sons, Inc. 相似文献
2.
Villano SM Eyet N Lineberger WC Bierbaum VM 《Journal of the American Chemical Society》2008,130(23):7214-7215
The gas-phase reactivity of the CHCl*- anion has been investigated with a series of halomethanes (CCl4, CHCl3, CH2Cl2, and CH3Cl) using a FA-SIFT instrument. Results show that this anion primarily reacts via substitution and by proton transfer. In addition, the reactions of CHCl*- with CHCl3 and CH2Cl2 form minor amounts of Cl2*- and Cl-. The isotopic distribution of these two products is consistent with an insertion-elimination mechanism, where the anion inserts into a C-Cl bond to form an unstable intermediate, which eliminates either Cl2*- or Cl- and Cl*. Neutral and cationic carbenes are known to insert into single bonds; however, this is the first observation of such reactivity for carbene anions. 相似文献
3.
The synthesis of multifunctionalized β-ketoesters has been achieved by using molecular iodine as a catalyst under very mild conditions. The vinylogous addition of Chan’s diene 1 to carbonyl and carbonyl-related compounds (aldehydes, ketones, imines and acetals) occurred with high efficiencies and with complete γ-selectivity, giving a useful method for the synthesis of interesting libraries of different δ-functionalized β-ketoesters. 相似文献
4.
Arrigo Scettri Rosaria Villano Patrizia Manzo Maria Rosaria Acocella 《Central European Journal of Chemistry》2012,10(1):47-53
The first Mukaiyama-Michael vinylogous reaction of a dioxinone-derived silyl ether to nitroalkenes is reported. The conjugate
addition is performed in absence of any catalyst under solvent-free conditions, proceeding with satisfactory efficiency with
variously substituted nitroalkenes. 相似文献
5.
Rosaria Villano Maria Rosaria Acocella Antonio Massa Laura Palombi Arrigo Scettri 《Tetrahedron: Asymmetry》2006,17(24):3332-3334
Chiral δ-hydroxy-β-ketoesters are easily available through the enantioselective vinylogous aldol reaction of Chan’s diene promoted by a SiCl4/chiral phosphoramide catalytic system. The procedure is conveniently exploited for a very rapid approach to (+)-kavain, a natural bio-active -pyrone compound. 相似文献
6.
The competition between bimolecular nucleophilc substitution and base-induced elimination is investigated through kinetic isotope effect measurements for gas-phase reactions of RCl + ClO- (R = methyl, ethyl, isopropyl, and tert-butyl) utilizing a FA-SIFT instrument. The overall reaction rate constants and the kinetic isotope effect for the reaction of C2H5Cl + ClO- are compared to computational results. [Hu, W. P.; Truhlar, D. G. J. Am. Chem. Soc. 1996, 118, 860.] Experimental results show that as the degree of substitution in the neutral reactant increases the E2 channel becomes dominant. The systematic change in the overall kinetic isotope effects indicates that, for the reaction of ClO- with C2H5Cl, both the SN2 and E2 pathways do occur, as predicted by computation; however the experimental reaction rate constants and KIE deviate strongly from the computational result. 相似文献
7.
Rosaria Villano 《Tetrahedron letters》2007,48(5):891-895
Hydrogen-bonding activation of aromatic aldehydes by a TADDOL-derivative promotes the vinylogous aldol reaction of Chan’s diene in moderate efficiency and enantioselectivity. Electron-poor aromatic aldehydes show an enhanced reactivity and a competing asymmetric hetero-Diels-Alder reaction takes place in comparable (or higher) yields and enantiomeric excesses. 相似文献
8.
9.
P. Mormile P. Musto L. Petti G. Ragosta P. Villano 《Applied physics. B, Lasers and optics》2000,70(2):249-252
An electro-optical characterisation of a polymer-dispersed liquid crystal (PDLC) based on unsaturated polyester (UP) resin,
recently prepared in our laboratory, is presented. Transmittance and response times as a function of an electric field applied
to the sample, have been measured taking into account also the morphological aspects of various samples. The experimental
results confirm the theoretical data previously calculated on the base of the dimensions of the liquid-crystal droplets inside
the polymeric matrix. Our analysis on this new material suggests the possibility of employing such a PDLC to realise electro-optical
devices.
Received: 9 October 1998 / Revised version: 12 May 1999 / Published online: 21 January 2000 相似文献
10.
Takatoshi Ichino Dr. Stephanie M. Villano Dr. Adam J. Gianola Dr. Daniel J. Goebbert Dr. Luis Velarde Dr. Andrei Sanov Prof. Stephen J. Blanksby Dr. Xin Zhou Dr. David A. Hrovat Dr. Weston Thatcher Borden Prof. W. Carl Lineberger Prof. 《Angewandte Chemie (International ed. in English)》2009,48(45):8509-8511