Evaluation of Antifungal and Antioxidant Activity of Newly Synthesized 4‐Thiazolidinones

The antifungal and antioxidant activities of thirty newly synthesized 4‐thiazolidinone (TZON) derivatives were assessed against some fungal species including Candida albicans and Aspergillus niger. The introduction of different arylidene moieties at 5‐positions of the thiazolidinone ring successfully enhanced its biological activity. The structure–activity relationships revealed that 4‐thiazolidinone derivatives harboring dicarboxyethyl (at the 2‐ethenyl) and p‐nitrophenylhydrazyl arm (at the 5‐arylidine positions of the thiazolidinone ring) display considerable antifungal and antioxidant properties.     

Synthesis and Reaction of Some Indenopyridine and Thieno[2,3-b]Indeno[2,1-e]Pyridine Derivatives

Synthesis of indenopyridine-2-thione derivatives 6a-e via reaction of compound 1 with thioamides 2a-e in good yields. Several thieno[2,3-b]indeno[2,1-e]pyridine 9a-e have been synthesized. Some of them was used as a key intermediate in synthesis of 10-12. On the other hand, compound 1 reacted with various reagents to yield 16, 19, 21-24.     

Simplified Approach to the Uncatalyzed Knoevenagel Condensation and Michael Addition Reactions in Water using Microwave Irradiation

Use of microwave irradiation in the synthesis of arylidenemalononitrile and benzopyran derivatives in water without catalyst is a clean method with high yield.     

Novel Cyanoketene N,S‐Acetals and Pyrazole Derivatives using Potassium 2‐Cyanoethylene‐1‐thiolates

Novel ketene N,S‐acetals 3 were readily prepared by the reaction of cyanoacetamide or cyanothioacetamide with phenylisothiocyanate in the presence of potassium hydroxide, followed by alkylation of the produced salts with methyl iodide. The reaction of compounds 3 with hydrazines afforded different substituted pyrazoles 6.     

Corrosion inhibition of zinc in aqueous acidic media using a novel synthesized Schiff base – an experimental and theoretical study

Abstract

The kinetics of H₂ production during Zn corrosion in 0.5?M HCl without and with various additives of N,N'-bis-(1-hydroxyphenylimine)-2,5-thiophenedicarboxaldehyde (HPTD) was studied using gasometry and electrochemical techniques. The surface of the corroded Zn samples was investigated using SEM and Optical Profilometry. The rate of H₂ production (RHP) increased with the immersion time and temperature. Presence of HPTD mitigated RHP due to an adsorption process. The electrochemical impedance spectroscopy showed that HPTD had a good inhibitive effect. Polarization data proved that HPTD acted as a surface-active mixed-type inhibitor. Some thermodynamic parameters were deduced and discussed. Theoretical calculations were also conducted to corroborate the capability of HPTD to protect Zn surface from corrosion process.     

Synthesis,Characterization, and Antimicrobial Activity of Carboxymethyl Chitosan-Graft-Poly(N-acryloyl,N′-cyanoacetohydrazide) Copolymers

Carboxymethyl chitosan was grafted with N-acryloyl,N′-cyanoacetohydrazide in homogenous aqueous phase using potassium persulfate initiator. The maximum grafting yield achieved was 448% at 0.03 mol/L potassium persulfate, 0.75 mol/L N-acryloyl,N′-cyanoacetohydrazide, and 60°C within 2 h. The grafted copolymers showed better thermal stability than that of carboxymethyl chitosan. The samples with percent grafting values up to 98% were soluble in water, but a higher grafting extent resulted in insoluble copolymers. The grafted copolymers are nontoxic materials and showed an inhibition effect on both Escherichia coli and Staphylococcus aureus bacteria and Aspergillus flavus and Candida albicans fungi better than those of chitosan and carboxymethyl chitosan themselves.     

Substituted quinolinones. 18. 3-Acetyl-4-methylthioquinolin-2(1H)-one as useful synthon intermediate for synthesis of some new quinolinones

3-Acetyl-4-methylthioquinolin-2(1H)-one (3) has been prepared and its reactivity towards treatment with different reagents, dilute sulfuric acid, aqueous sodium hydroxide, and hydrogen peroxide, is described. The reactions of compound 3 with benzylamine, benzaldehyde, DMF-DMA, Vilsmeier-Haack reagent, 2-chloro-3-formyl-pyridopyrimidone and malononitrile have been carried out under convenient conditions. Compound 3 underwent heterocyclization reactions with some binucleophiles, hydrazine, hydroxylamine, urea, thiourea, semicarbazide, and thiosemicarbazide, furnishing some known five, six, and seven heterocyclic annellated quinolines. All the new compounds have been characterized using different spectral and analytical tools.     

Synthesis of some new pyrimidine derivatives and evaluation of their anticancer and antibacterial activities

Starting from the reaction of ethyl cyanoacetate with thiourea and the appropriate aldehydes, a series of new pyrimidine derivatives were prepared. Ten selected pyrimidine derivatives were subjected to a screening system for the investigation of their antitumor potency against liver (HEPG2) cell line. The antitumor activity results indicated that most of the selected pyrimidine derivatives showed moderate growth inhibition activity against the tested cell line, but with varying intensities in comparison to the known anticancer drugs: 5-fluorouracil and doxorubicin. Some of the synthesized compounds were also tested for their antimicrobial activity against bacteria as well as fungal isolates.     

Asymmetric aldol reactions catalyzed by the promiscuous aldo–ketoreductase enzyme

The promiscuous aldo–ketoreductase (AKR) enzyme is used as a sustainable biocatalyst for the first time to catalyze asymmetric aldol reactions in aqueous medium. The reactions between aromatic aldehydes and cyclic/acyclic ketones give the corresponding products in moderate yields and enantioselectivities in the presence of water. The influence of solvents, the mole ratio of substrates, and enzyme concentration are investigated. The mechanism of the AKR1A1-catalyzed aldol reaction is also discussed.     

Preparation and Characterization of Modified Cellulose Adsorbents with High Surface Area and High Adsorption Affinity for Hg(II)

Cellulose was modified via chlorination using phosphorous oxychloride followed by functionalization with amine and thiol moieties. The obtained modified cellulose samples were investigated by means of FTIR, TGA, TEM, and nitrogen-adsorption surface area (BET). The BET measurements showed a remarkable increase in the surface area of Cell-N-S (477.7 m²/g) and Cell-N (706 m²/g). The resins gave an uptake capacities of 38 and 7.2mmol/g for Cell-N-S and Cell-N, respectively toward Hg(II) from its solutions. These values are considered much better compared with other reported resins. Regeneration of the resins was achieved effectively using acidified thiourea.