Microwave-assisted synthesis,antimicrobial, antiquorum-sensing and cytotoxic activities of a new series of isatin-β-thiocarbohydrazones

Abstract

New isatin-β-thiocarbohydrazone hybrids 4-17 were designed relied on isatin scaffold to generate various analogs with expected antimicrobial activity. The new hybrids were estimated for antibacterial effectiveness over S. aureus, B. cereus and E. coli, and antifungal efficacy over C. albicans and A. fumigatus. Compound 14 evinced the highest efficacy over A. fumigatus and C. albicans. In addition, 5 and 12 showed eminent efficacy toward A. fumigatus, where compounds 4, 7, 9, 11, 13, 15 and 16 exhibited moderate activity over the same fungus. Moreover, 6 and 9 displayed moderate activity over C. albicans. The new compounds were also estimated for antiquorum-sensing effectiveness against C. violacium, where compound 17 showed interesting activity. In vitro cytotoxicity assay of the new analogs was done over Hela and COS-7 cancer cell lines. All analogs have IC₅₀ values >50?μM toward both cell lines.     

Ferroelectric phase transition in Ga2Te3 single crystals

Measurements of the electrical conductivity and Hall effect were carried out in a wide temperature range (200-500 K) for Ga₂Te₃ crystals. The crystals were grown in single crystalline form by making a modification of the travelling heater method technique. The measurements revealed unusual observations in the electric conductivity and Hall mobility indicating the presence of some type of phase transitions at about 430 K. So, ferroelectric behavior was examined for confirming the presence of second-order (ferroelectric) phase transition. An energy gap of 1.21 eV and depth of the impurity center of 0.11 eV were found.     

Second-class currents in 0−→0+ and unique nuclear β transitions

The induced pseudotensor contribution to 0^? → 0⁺ and uniqueβ transitions has been analyzed starting from two possible forms of the nonrelativistic Hamiltonian. The role of mesonic corrections and mesonic second-class currents has been discussed     

Development of a differential pulse voltammetric method for the determination of Silymarin/Vitamin E acetate mixture in pharmaceuticals

Differential pulse voltammetric method was developed for determination of Silymarin (SMR)/Vitamin E acetate (VEA) mixture in pharmaceuticals. SMR and VE gave well-resolved diffusion-controlled anodic peaks at +756 and +444mV, respectively (versus Ag/AgCl) in Britton-Robinson buffer at pH 2.8. The solution conditions and instrumental parameters were optimized for their quantitative determination. The linear response was obtained in the range 0.1-4.0mgL(-1) with a detection limit of 0.03mgL(-1) for SMR and 0.05-4.0mgL(-1) with a detection limit of 0.01mgL(-1)for VEA.     

Development of a Novel Automatic Potentiometric System for Determination of Selenium and Its Application in Pharmaceutical Formulations and Anodic Slime

Poly(vinyl chloride) polymeric membrane sensors containing Sn(IV) phthalocyanine dichloride (SnPC) and Co(II) phthalocyanine (CoPC) as novel electroactive materials dispersed in o‐nitrophenyl octylether (o‐NPOE) as a plasticizer are examined potentiometrically with respect to their response toward selenite (SeO₃^2?) ions. Fast Nernstian response for SeO₃^2? ions over the concentration ranges 7.0×10^?6–1.0×10^?3 and 8.0×10^?6–1.0×10^?3 mol L^?l at pH 3.5–8.5 with lower detection limit of 5.0×10^?6 and 8.0×10^?6 mol L^?1 and calibration slopes of ?25.4 and ?29.7 mV decade^?1 are obtained with SnPC and CoPC based membrane sensors, respectively. The proposed sensors reveals by the modified separate solution method (MSSM) a good selectivity over different anions which differ significantly from the classical Hofmeister series. A segmented sandwich membrane method is used to determine complex formation constants of the ionophores in situe in the solvent polymeric sensing membranes. Membrane incorporating CoPC in a tubular flow detector is used in a two channels flow injection set up for continuous monitoring of selenite at a frequency of ca. 50 samples h^?1. Direct determination of selenium in pharmaceutical formulations and anodic slime gives results in good agreement with data obtained using standard ICP method.     

Real-time monitoring of protein complexes reveals their quaternary organization and dynamics

The dynamics of protein complexes are crucial for their function yet are challenging to study. Here, we present a nanoelectrospray (nESI) mass spectrometry (MS) approach capable of simultaneously providing structural and dynamical information for protein complexes. We investigate the properties of two small heat shock proteins (sHSPs) and find that these proteins exist as dodecamers composed of dimeric building blocks. Moreover, we show that these proteins exchange dimers on the timescale of minutes, with the rate of exchange being strongly temperature dependent. Because these proteins are expressed in the same cellular compartment, we anticipate that this dynamical behavior is crucial to their function in vivo. Furthermore, we propose that the approach used here is applicable to a range of nonequilibrium systems and is capable of providing both structural and dynamical information necessary for functional genomics.     

Electrochemical Characterization of Carbon Solidlike Paste Electrode Assembled Using Different Carbon Nanoparticles

Solid like carbon paste electrodes (SCPEs) are built using different carbon materials namely carbon black N110, N220, N375, N772 and acetylene black. The electrochemical behavior of these electrodes and the influence of carbon black/paraffin ratio were studied and the results were discussed and compared to other electrodes prepared with graphite, mesoporous carbon and nanopowder carbon. Cyclic voltammetry, amperometry and electrochemical impedance spectroscopy were employed for their electrochemical and analytical characterizations. Amperometric measurements using N110, N220, N375 SCPEs with solid paraffin, showed a linear response of benzoquinone concentration with a detection limit of 75, 32 and 171 nM respectively.     

Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl-4H-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity

A novel group of 6-iodoquinazolin-4(3H)-one derivatives was prepared. The reaction of the benzoxazinone 3 with various nitrogen nucleophiles such as formamide and hydrazine hydrate and also the reaction of the isopropylquinazolinone 4 with hydrazonyl chloride have been shown to proceed with a high degree of regioselectivity at C(2). Spiro heterocycles have been found to play fundamental roles in biological processes and have exhibited diversified biological activity and pharmacological and therapeutical properties; thus reaction of acetohydrazides 10a–c afforded the spiro compounds 11a–c. The acetohydrazide derivative 7 reacted with carbon electrophiles such as acetylacetone, ethyl acetoacetate, acid chlorides, and benzaldehyde to give some interesting heterocyclic compounds 12–16, respectively. The structures of all the synthesized compounds were inferred by infrared, ¹H NMR, and mass spectra as well as elemental analyses. The antimicrobial activities of some of the synthesized products were preliminarily evaluated.     

6-Iodo-2-isopropyl-4H-3,1-benzoxazin-4-one as building block in heterocyclic synthesis

As a part of ongoing studies in the synthesis of a variety of heterocycles of biological importance, we report here an efficient and convenient method for the synthesis of novel compounds from 6-iodo-2-isopropyl-4H-3,1-benzoxazin-4-one 1 as building block. The reaction of benzoxazinone 1 with various reagents such as diethylmalonate, sodium azide, and phosphorus pentasulfide yielded the compounds 2–5. The behavior of benzothiazin-4-thione 5 toward formamide and hydrazine hydrate was investigated, forming the compounds 6 and 7. The reaction of quinazolinone derivative 8 with β-D-glucose pentaacetate, ethyl 2-methyl-5-((1S,2R,3R)-1,2,3,4-tetrahydroxybutyl)furan-3-carboxylate, epichlorohydrin and benzenesulphonyl chloride afforded quinazolinone derivatives 9, 10, 12, and 13 respectively. The reaction of quinazolinone derivative 10 with acetic anhydride resulted in formation of the acylated compound 11. The behavior of quinazolinylacetohydrazide derivative 14 toward carbon electrophiles^[16 El-Hashash, M. A.; El-Naggar, A. M.; El-Bordany, E. A.; Marzouk, M. I.; Nawar, T. M. S. Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl4H-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity. Synth. Commun. 2016, 46(14), 1230–1241.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]^] has been investigated by its reaction with ethyl benzoylacetate, potassium thiocyanate, and phenyl isothiocyanate, affording the quinazolinone derivatives 15, 16, and 18, respectively. Treatment of compound 16 with sodium hydroxide followed by hydrochloric acid yielded the mercapto-triazole derivative 17. The structures of the newly synthesized compounds were confirmed by elemental analysis, infrared (IR), ¹H NMR, ¹³C NMR, and mass spectra. The antimicrobial activities of some of the synthesized compounds were preliminarily evaluated.     

Itaconamide derivatives as organic stabilizers for poly(vinyl chloride) against photodegradation

Itaconamide derivatives have been prepared and investigated as photo-stabilizers for rigid PVC. We investigated their stabilizing efficiencies by testing the weight loss (%) with the amount of formed gel. The results indicated a reasonable stabilizing efficiency of these derivatives compared with commercial UV absorber; phenyl salicylate. The extent of discoloration of the photodegraded polymer was also improved in the presence of the prepared compounds. Rheological properties were studied to investigate the flow behavior with providing a vision into the mechanical behavior for the tested materials. Employing the evaluated photostabilizers reflects the reduction in the extent of cross-linking of the polymer. This implies preserving the mechanical properties of PVC. A radical mechanism is proposed to account for the stabilizing action of the investigated materials. The prepared itaconamide derivatives provide appropriate photostability and mechanical properties for a durable poly(vinyl chloride).