Synthesis, characterization, tautomerism and theoretical study of some new Schiff base derivatives

New Schiff base derivatives were prepared by the condensation of 5-chloro and 5-bromo salicylaldehyde with bis(o-aminophenol)ethers. Five bis(o-nitrophenol)ether compounds were synthesized using some ditosylate, 1,3-dibromopropane and 1,4-dibromobuthane with o-nitrophenol. These compounds were reduced to bis(o-aminophenol)ethers. The products have been characterized by elemental analysis, FTIR, 1H, 13C NMR, HETCOR and HMBC spectroscopic techniques. The tautomerisms of all of the Schiff bases compounds were determined in DMSO, CHCl3, C2H5OH and C6H12 solvents and in both acidic and basic media using the UV-vis spectrophotometric method. The heat of formation (ΔHf), enthalpy (ΔH), entropy (ΔS), Gibbs free energy (ΔGf and ΔG), stable isomers, conformations and tautomers of the synthesized compounds are calculated using the MOPAC2009 (PM6) program.     

Photochemically prepared polysulfone/poly(ethylene glycol) amphiphilic networks and their biomolecule adsorption properties

Polysulfone/poly(ethylene glycol) amphiphilic networks were prepared via in situ photo-induced free radical crosslinking polymerization. First, the hydrophobic polysulfone diacrylate (PSU-DA) oligomer was synthesized by condensation polymerization and subsequent esterification processes. Then, the obtained oligomer was co-crosslinked with the hydrophilic poly(ethylene glycol) diacrylate (PEG-DA) or poly(ethylene glycol) methyl ether acrylate (PEG-MA) at different feed ratios. In the case of PEG-MA, the resulting network possessed dangling pendant hydrophilic chains on the crosslinked surface. The structure and the morphology of the membranes were characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM). The enhancement of surface hydrophilicity was investigated by water contact angle measurements. The biomolecule adsorption properties of these networks were also studied. The biomolecules easily adsorbed on the surface of the hydrophobic polysulfone networks whereas dangling hydrophilic chains on the surface prevented the adsorption of the biomolecules.     

Reactivity Study of 2,4-Dinitrobuta-1,3-Dienes Towards Mono-, Poly-, and Persulfanyl Conjugated Dienes by Regiospecific Vinyl Group Activation

Abstract

Polyhalogenated nitrobuta-1,3-dienes are unique reagents in organic synthesis and have been employed in several well-known and recently developed areas of application. This study describes the scope and application of 1,1,3,4-tetrachloro-2,4-dinitrobuta-1,3-diene in organic synthesis as well as methods for the preparation of poly- and perfunctionalized 2,4-dinitrobuta-1,3-dienes, and characterization of all obtained compounds.     

SOME NEW S-, S,S- AND N,S-SUBSTITUTED 2-NITRODIENES AND BUTADIENYL-SUBSTITUTED PIPERAZINES

Nitrodiene 1 reacted with 2a, b and gave the novel compounds 3a, b, 4a, b, and 5a. Monosubstituted diene compound 3a gave the compounds 9a with morpholine, 11a with piperidine, and 13a with homopiperazine. Compound 3a gives the thioether compound 15 by the reaction with the dithiol (HS─(CH₂)₂─O─(CH₂)₂─SH) in ethanol containing sodium hydroxide.     

Synthesis of Dibutadienyl Piperazines, 1,1-Dithio and 1,4-Dithio Substituted Dienes from Nitrodienes

Nitrodiene 1a , 1b reacted with 1,4-dithiolbutan and gave the heterocyclic compounds 3a , 3b . 1b gave with 1,3-acetonedithiol the compound 5b . The nitrodiene compound 1b reacted with o-dithiolbenzene ( 6 ) and yielded the ketene dithioacetal ( 7b ). Heterocyclic compounds 11a , 11b , 12a , and 12b were prepared from the reactions of 9a with 2,2'-oxydiethanethiol. The compounds 9a , 9b were prepared from 2-nitropentachloro-1,3-butadiene and alkylthiols ( 8a , 8b ). Mono(thio) substituted diene compound 9b gave dibutadienyl piperazine 14b with piperazine in diethylether.     

Synthesis of Novel Thioethers and Sulfoxide Compounds

Abstract

Thiosubstituted butadiene and butenyne compounds were synthesized from the reactions of 1,1,3,3,4,4-hexachloro-1-butene or 1,1,2,4,4-pentachlorobuta-1,3-diene with different thiols in EtOH/H₂O solution of NaOH. Tris(thio)substituted butadiene compound was treated with potassium tert-butoxide to obtain tris(thio)substituted butatrienyl halide compound. The novel sulfoxide compounds were synthesized from the reactions of polyhalobutadiene compounds with aliphatic thiols in CHCl₃ with m-CPBA at 0°C. The structures of the novel compounds were characterized by micro analysis, FT-IR, ¹H-NMR, ¹³C-NMR, and MS.     

Synthesis of Some Novel S- and N,S-Substituted Chlorobutadienes

Abstract

Mono(thio)substituted nitrodienes were synthesized by reactions of 2-nitro-pentachloro-1,3-butadiene with some thiols [(tert-butylbenzyl)thio- and 2,3,5,6-tetra-fluorophenylthio-] either directly or in ethanol in the presence of sodium hydroxide. N,S-Substituted 1,3-butadienes were obtained from the reaction of the mono(thio)substituted nitrodienes with morpholine and some piperazine derivatives in dichloromethane. Also mono- and di(thio)substituted perchlorobutadienes were synthesized from the reactions of hexachloro-1,3-butadiene with o-aminothiophenol in ethanol in the presence of sodium hydroxide. The structures of the new compounds were characterized by microanalysis and spectroscopic data.     

Fixed points in intuitionistic fuzzy metric spaces

The purpose of this paper, using the idea of intuitionistic fuzzy set due to Atanassov [Atanassov K. Intuitionistic fuzzy sets. Fuzzy Sets Syst 1986;20:87–96], we define the notion of intuitionistic fuzzy metric spaces due to Kramosil and Michalek [Kramosil O, Michalek J. Fuzzy metric and statistical metric spaces. Kybernetika 1975;11:326–34]. Further the well-known fixed point theorems of Banach and Edelstein are extended to intuitionistic fuzzy metric spaces with the help of Grabiec [Grabiec M. Fixed points in fuzzy metric spaces. Fuzzy Sets Syst 1988;27:385–9].     

ON THE EXISTENCE OF PERIODIC SOLUTIONS TO A CERTAIN FOURTH-ORDER NONLINEAR DIFFERENTIAL EQUATION

In this paper, we consider a certain fourth-order nonlinear ordinary differential equation. Some sufficient conditions which guarantee the existence of at least one ω-periodic solution to the system are obtain.     

Global asymptotic stability and boundedness of certain multi‐delay functional differential equations of third order

In this paper, the authors give sufficient conditions for the boundedness and global asymptotic stability of solutions to certain nonlinear multi‐delay functional differential equations of the third order. The technique of proof involves defining an appropriate Lyapunov‐Krasovskii functional and applying LaSalle's invariance principle. An example is included to illustrate the results. Copyright © 2014 John Wiley & Sons, Ltd.