Intramolecular Aldol Condensation of a - Oxo Ketene Dibenzylthioacetals: A Facile Route to Substituted Thiophenes

A new method for the synthesis of substituted thiophenes was through intramolecular aldol condensation of α-oxo ketene dibenzylthioacetals.All products were confirmed with IR,1H NMR and elemental analysis.     

SYNTHESIS AND CHARACTERIZATION OF POLY(ARYL ETHER KETONE)FROM 4-(3-PHENYL-4-HYDROXYPHENYL)PHTHALAZINONE

A novel soluble poly(aryl ether ketone) was prepared by the reaction of 4-(3-phenyl-4-hydr-oxyphenyl)phthalazinone with 4,4'-difluorobenzophenone. The polymer was characterized by DSC, TGA andX-ray diffraction.     

Synthesis and Effect of Cation Binding on Photophysical Properties of 1,8-Anthraceno-18-Crown-5

ThesystemsconsistingofafluorophorelinkedtoacrownethermoietyareeXtensivelyinvestigated'-'.Sincedrasticchangesintheirphotophysicalpropertiescanbeobservedbycomplexationwithion,theycanbeusedforionicdetection"'.Recentreportsfocusonazamacrocyclicderivativeswithfluorophores"',inwhichthefluorophoreandcrownethermoietywerelinkedvianitrogenatom.Thepresenceofabasicnitrogenatomwhichiseasytobeprotonatedleadstoelthancementoffluorescencequantumyield""'.Wereplacedthenitrogenatomofthecrownbyoxygenwhichisexpect…     

Eco-friendly polyethylene glycol-400: a rapid and efficient recyclable reaction medium for the synthesis of thiazole derivatives

Abstract

An efficient and convenient procedure for the synthesis of thiazole derivatives from α-haloketone, thiourea and substituted acetophenones using polyethylene glycol-400 as a green and recyclable solvent is described. Significant rate enhancement and improved yields have been observed.     

Water mediated synthesis of various [1,3]oxazine compounds using alum as a catalyst

Abstract

A simple, efficient, and practical procedure for the synthesis of various substituted 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e][1,3]oxazines and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazines using KAl(SO₄)₂ 12H₂O (alum) as a non-toxic, reusable, inexpensive, and easily available catalyst is described using water as a solvent. These improved reaction conditions allow the preparation of a wide variety of substituted [1,3]oxazines in high yields and purity under mild reaction conditions.     

Synthesis,thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

A series of poly(benzylidene‐ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6‐bis(4‐hydroxy‐3‐methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT‐IR, ¹H NMR, and ¹³C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self‐extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd‐even effect has been observed. Hot‐stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene‐ether)esters revealed that α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Crown ether complexes of tin(II) trifluoromethanesulfonate

The treatment of tin(II) trifluoromethanesulfonate with three differently-sized crown ethers [12]crown-4, [15]crown-5 and [18]crown-6 results in the formation of tin complexes that exhibit dramatically different structural features. The compounds are investigated using experimental techniques and density functional theory calculations.     

Fatty acid amide hydrolase inhibitors. 2. Novel synthesis of sterically hindered azabenzhydryl ethers and an improved synthesis of VER-156084

We report an improved synthesis of the fatty acid amide hydrolase (FAAH) inhibitor VER-156084. The key step is a novel, environmentally benign etherification to form an unusual, highly hindered azabenzhydryl ether. The method is applied to a variety of primary and secondary alcohols.     

Ammonium Ion Optical Sensor Formation and Characterization of a Self‐Assembled Thiazole Containing Dibenzo‐18‐Crown‐6 Monolayer toward Developing Ammonium Ion‐Sensing Interface

Abstract

This letter demonstrates a selective NH₄ ⁺ detection using a synthesized thiazole benzo crownether ethylamine‐lipoic acid conjugate (1) monolayer. A self‐assembled monolayer (SAM) of 1 was formed on Au surface and well characterized by atomic‐force microscopy, Fourier transform infrared reflection absorption spectroscopy and cyclic voltammetry (CV). A good selectivity for NH₄ ⁺ sensing was observed in a range of 1.0×10^?1 to 1.0×10^?6 M by surface plasmon resonance.