Salem A. Basaif

Synthesis and spectral characterization of novel 1,3,4-oxadiazole and 1,2,4-triazole derivatives: Synthesis for potential pharmacological activities

Oxadiazole derivatives ( 3a , b ) and ( 4a , b ) were obtained in a good yield by the reaction of the benzylidene derivatives ( 2a , b ) with acetic anhydride and yellow mercuric oxide respectively. Cyclodesulfurization of the thiosemicarbazide derivatives ( 5a-c ) with yellow mercuric oxide afforded the oxadiazoles ( 7a-c ). On the other hand, reaction of ( 5a-c ) with sodium hydroxide gave the triazoles ( 6a-c ). The structures of the isolated products were fully determined by spectral methods.

Synthesis of a new β-naphthothiazole monomethine cyanine dye for the detection of DNA in aqueous solution

Novel monomethine cyanine dye (MC) derived from beta-naphthothiazole and benzothiazole has been prepared and characterized by (1)H and (13)C NMR, FTIR, ESIMS, elemental analyses, absorption and fluorescence spectroscopy. The dye was conveniently synthesized by the condensation of two sulfate heterocyclic quaternary salts. The interaction between calf thymus DNA (ct-DNA) in tris(hydroxymethyl)aminomethane-HCl (Tris-HCl) aqueous buffer solution and MC has been studied with spectral fluorescence method. The binding constant value has been determined by fluorescence titration of MC with ct-DNA concentrations. The result obtained is consistent with an intercalative binding interaction between MC and ct-DNA. Compared with ethidium bromide (EB), MC showed a huge fluorescence enhancement upon mixing with ct-DNA.

Synthesis and biological evaluation of some novel urea and thiourea derivatives of isoxazolo[4,5-d]pyridazine and structurally related thiazolo[4,5-d]pyridazine as antimicrobial agents

This study reports the synthesis of some novel isoxazolo[4,5-d]pyridazines and structurally related thiazolo[4,5-d]pyridazines, and their biological evaluation as antimicrobial agents. The proposed compounds were designed to contain pharmacophores such as urea, thiourea, sulfonylurea (thiourea) and some derived functionalities that are believed to contribute to the anticipated biological activities. The results revealed that 25 compounds displayed broad spectrum of antibacterial activity, with greater inhibitory effect on the growth of the tested Gram positive strains compared to Gram negative ones. Moreover, 14 compounds were able to produce appreciable growth inhibitory activity against Candida albicans fungus when compared to Clotrimazole. Most of the tested isoxazolo[4,5-d]pyridazines displayed better antimicrobial profile than their corresponding thiazolo[4,5-d]pyridazine congeners. Four compounds namely, p-(3,7-dimethyl-4-oxo-4H-isoxazolo [4,5-d]pyridazine-5-yl)benzenesulfonylthioureas (11c–d), 3-substituted-2-[p-(3,7-dimethyl-4-oxo-4H-isoxazolo[4,5-d]pyridazine-5-yl)-benzene-sufonylimino]-4-oxothiazolidines (13d) and p-(2,7-dimethyl-4-oxo-4H-thiazolo[4,5-d]pyridazin-5-yl)benzenesulfonylthiourea (24c) were found to be most active antimicrobial members in present study.

Synthesis and characterization of some hydroxypyridone derivatives and their evaluation as antimicrobial agents

The synthesis, in vitro antimicrobial activities of some novel hydroxy pyridines supported with various pharmacophores is described. Twenty-six out of the tested 58 compounds exhibited variable inhibitory effects on the growth of the tested Gram positive and Gram negative bacteria. The tested compounds revealed better activity against the Gram positive rather than the Gram negative strains. The synthesized hydroxypyridones have shown very significant inhibitory effect against Staphylococcus aureus and Bacillus subtilis. Twelve compounds namely; 5d, 5f, 6a, 6b, 8b, 18b, 18c, 19c, 21d, 22b, 22d and 23d were able to produce appreciable growth inhibitory activity against Candida albicans when compared to Clotrimazole. Among these, 22d proved to be the most potent antifungal agent.

An electro-optical and electron injection study of benzothiazole-based squaraine dyes as efficient dye-sensitized solar cell materials: a first principles study

AbstractSquaraine dyes have attracted significant attention in many areas of daily life from biomedical imaging to semiconducting materials. Moreover, these dyes are used as photoactive materials in the field of solar cells. In the present study, we investigated the structural, electronic, photophysical, and charge transport properties of six benzothiazole-based squaraine dyes (Cis-SQ1–Cis-SQ3 and Trans-SQ1–Trans-SQ3). The effect of electron donating (−OCH3) and electron withdrawing (−COOH) groups was investigated intensively. Ground state geometry and frequency calculations were performed by applying density functional theory (DFT) at B3LYP/6-31G** level of theory. Absorption spectra were computed in chloroform at the time-dependent DFT/B3LYP/6-31G** level of theory. The driving force of electron injection (ΔGinject), relative driving force of electron injection (ΔGrinject), electronic coupling constants (|VRP|) and light harvesting efficiency (LHE) of all six compounds were calculated and compared with previously studied sensitizers. The ΔGinject, ΔGrinject and |VRP| of all six compounds revealed that these sensitizers would be efficient dye-sensitized solar cell materials. Cis/Trans-SQ3 exhibited superior LHE as compared to other derivatives. The Cis/Trans geometric effect was studied and discussed with regard to electro-optical and charge transport properties. Graphical AbstractBenzothiazole-based squarainedyes as efficient dye-sensitized solar cell materials

4-(3-Methyl-5-phenyl-1H-pyrazol-1-yl)benzene­sulfonamide

With respect to the planar five-membered ring of the title compound, C16H15N3O2S, the phenyl ring is aligned at 47.0 (1)° and the phenylene ring at 37.6 (1)°. The amino group has the N atom in a pyramidal geometry; the group is a hydrogen-bond donor to the sulfonyl O atom of one molecule and to the pyrazole N atom of another molecule, resulting in the formation of a layer parallel to the bc plane.

Synthesis of N 1 -Substituted, N 3 -[ P -(3-Ethoxy-Carbonyl-4,5-Dihydronaphtho[1,2- c ]Pyrazol-2-YL)Benzenesulfonyl]Urea and Thiourea Derivatives. Class of Cyclooxygenase-2 Inhibitors

Several urea and thiourea derivatives ( 2a-f ) were prepared by the reaction of dihydronaphthopyrazolylbenzenesulfonamide ( 1 ) with the corresponding isocyanates and isothiocyanates, respectively. The benzenesulfonylthioureas ( 2d , e ) were cyclized with ethyl bromoacetate, ethyl g -bromopropionate and f -bromoacetophenones to give the corresponding 4-oxothiazolidine ( 3a , b ), 4-oxo-5,6-dihydrothiazine ( 4a , b ) and thiazoline derivatives ( 5a-d ) respectively.