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Copolymers of linear and aromatic polysulfide blocks are synthesized using interfacial polymerization of dichloro-xylene-based aromatic and ethylene-dichloride-based non-aromatic organic monomers. Synthesized copolymers consist of poly(ethylene sulfide) as well as ploy (xylene sulfide) blocks. Fascinating properties of linear and aromatic polysulfide species are gathered in the structure of synthesized polysulfide copolymers. Ethylene dichloride and α,α′-dichloro-p-xylene are used as the non-aromatic and aromatic organic monomers, respectively. To investigate the influences of sulfur contents in the backbone of the polymer on the thermal stability of synthesized copolymers, poly(ethylene-xylene disulfide) (PEXDS), poly(ethylene-xylene trisulfide) (PEXTRS) and poly(ethylene-xylene tetrasulfide) (PEXTS) copolymers are synthesized using, respectively, sodium disulfide, sodium trisulfide and sodium tetrasulfide, as aqueous monomers. Compared to both linear and nonlinear homopolymers, synthesized copolymers exhibit improved thermal stability. Moreover, the thermal degradation temperatures of synthesized copolymers improve by decreasing the number of sulfur atoms in the backbone of copolymers. These results reveal that thermal degradation of polysulfide copolymers can be tailored by controlling the polysulfide chain’s sulfur contents. Structural characteristics of synthesized polysulfide copolymers are also investigated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A molecular imprinting polymer (MIP) based on free-radical polymerization was prepared with allyl glycidyl ether/iminodiacetic acid as functional monomers and copper ion-atenolol as the template. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and scanning electron microscopy. The MIP of agglomerated micro-particles with multipores was used for solid phase extraction (SPE). The imprinted polymer sorbent was selective for the template. The profile of atenolol uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. In addition, the equilibrium adsorption data of atenolol by MIP were analyzed by isotherm models. The MIP–SPE was the most feasible technique for the extraction of atenolol up to 89.9% in the human plasma, up to 96.0% in human urine, and up to 95.3% in tablets where the recoveries were achieved. [ABSTRACT FROM PUBLISHER]

Indene and isoindene and their heteroanalogs (N,O,S) were inspected in the gas phase and three solvents (heptane, acetonitrile, and water) and in the presence of water as an explicit solvent from point of views of thermodynamic, NBO and NMR studies. These compounds can be considered in two classes: benzo[b] and benzo[c] isomers. The calculations were performed by the Gaussian 03 program at the B3LYP\6-311++G** level of theory. In all cases and conditions, the absolute values of Gibbs free energies for benzo[c] isomers are smaller than the benzo[b] isomers, and also for each isomer, the absolute values of these energies increase with increasing value of the dielectric constant. Also, in all conditions, indole and isoindole have the maximum values for resonance energy of LP(X) → π* and the maximum diatropic ring currents due to their aromaticity. [ABSTRACT FROM AUTHOR]

Ab initio density functional theory (DFT) calculations have been performed on the 3,3-sigmatropic rearrangements of 3-(vinyloxy)prop-1-ene (Claisen) and allyl vinyl sulfide (thio-Claisen) in the gas phase. The barrier height of the Claisen rearrangement calculated at the B3LYP/6-311G** level of theory was in good agreement with the corresponding experimental value. Optimized transition states at the B3LYP/6-311G** level were used for calculating of nucleus independent chemical shift (NICS) and also natural bond orbital (NBO) analysis at the same level. Our results indicate that aromaticities of the transition states are controlled by the out-of-plane component and that the strongest aromatic character is for the chair-like transition state of the thio-Claisen rearrangement. Analysis of donor-acceptor (bonding and antibonding) interactions suggests that the aromatic character of TS structure in the allyl vinyl sulfide reaction (the thio-Claisen rearrangement) is more than the 3-(vinyloxy)prop-1-ene reaction (the Claisen rearrangement). The NBO results show that in these rearrangements, activation energies are controlled by resonance energies. GRAPHICAL ABSTRACT[image omitted] [ABSTRACT FROM AUTHOR]

Reaction of 1-(2,2-dimethyl-propionyl)-3-{4-[3-(2,2-dimethyl-propionyl)thioureido]phenyl}thiourea or 1-(2,2-dimethyl-propionyl)-3-{5-[3-(2,2-dimethyl-propionyl)thioureido]naphthalen-1-yl}thiourea with dialkyl acetylenedicarboxylates in CH2Cl2 leads to alkyl (2-(2,2-dimethyl-propionylimino)-3-{4-[-(,2-dimethyl-propionylimino)-5-alkoxycarbonylmethylene-4-oxo-thiazolidin-3-yl]-phenyl}-4- oxo-thiazolidin-5-ylidene)acetates or alkyl (2-(2,2-dimethyl-propionylimino)-3-{5-[2-(2,2-dimethyl-propionylimino)-5-alkoxycarbonylmethylene-4-oxo-thiazolidin-3-yl]naphthalen-1-yl}-4-oxo-thiazo lidin-5-ylidene)acetates in good yields. [ABSTRACT FROM AUTHOR]

A convenient method for the synthesis of N-substituted-N'-arylcarbonylthioureas under solvent-free conditions has been developed. Ammonium thiocyanate and acid chlorides were mixed, and stirred at room temperature without a solvent, to give the corresponding isothiocyanates, which reacted smoothly with arylamines to produce the aryl(alkyl)carbonylthioureas in good yields. Unusually large values of 5JFH=12.2-15.1 Hz are observed for 1-(2-fluorobenzoyl)-thiourea derivatives, which provide information about the Ar-C-N-H torsions in these compounds. [ABSTRACT FROM AUTHOR]