Synthesis and antimycobacterial screening of new 4-(4-(1-benzyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-3-yl)quinoline derivatives

A new series of 4-(4-(1-benzyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-3-yl)quinoline ( 6a-t ) have been synthesized by a click reaction of 4-(4-ethynyl-1-phenyl-1H-pyrazol-3-yl)quinoline ( 4a-d ) with a substituted benzyl azide ( 5a-e ). The starting alkyne derivatives 4a-d are obtained from Bestmann-Ohira reaction of 1-phenyl-3-(quinolin-4-yl)-1H-pyrazole-4-carbaldehyde and dimethyl(1-diazo-2-oxopropyl)phosphonate. The newly synthesized compounds are screened against M. tuberculosis H37Ra dormant and active, Escherichia coli, Pseudomonas fluorescence, Staphylococcus aureus and Bacillus subtilis strains at 30 μg/mL concentration. Most of the screened compounds showed good to moderate antibacterial activity against S. aureus, B. subtilis, and Mycobacterium tuberculosis H37Ra strains. The synthesized derivatives of quinolinyl-pyrazole-4-carbaldehyde and quinolinyl-pyrazole-4-ethyne reportd good to moderate activity against both strains of M. tuberculosis H37Ra. Ten derivatives of quinolinyl-pyrazole presented good activity against B. subtilis. These results suggested that further optimization and development of quinolinyl-pyrazolyl-1,2,3-triazole moeity could serve as lead compounds for antimycobacterial activity.     

Ultrasound assisted,synthesis of N-(7-(R)-2-oxa-8-azabicyclo[4.2.0]octan-8-yl)isonicotinamide derivatives and their biological evaluation

In this study, new series of azetidine derivatives were synthesized ( 4a-n ) from isoniazide ( 1 ), Aromatic aldehydes ( 2a-n ), dihydropyran ( 3 ) using SnCl₂ catalyst, via one pot multicomponent reaction/cycloaddition reaction. The synthesized azetidine derivatives were characterized by IR, ¹H NMR and ¹³C NMR and have been screened for antimicrobial, antituberculosis and anti-inflammatory activities. In relation to Staphylococcus aureus (ATCC 25923) promising antibacterial activity was shown, compounds 4e and 4k , followed by compounds 4h , 4n , 4f , 4g and 4l . The synthesized azetidine derivatives, 4a , 4e , 4j and 4m (with zone 12 mm) displayed antituberculosis activity. But its lower potential than, the standard streptomycin (with zone 18 mm). Further 4d compound alone displayed similar activity.     

Simple efficient synthesis of 4‐aminoquinazoline via amidine of N‐arylamidoxime

Preparation of 4‐amino‐2‐aryl quinazolines by reduction of N‐(2‐cyanoaryl) amidoximes via amidines using SnCl₂ in ethanol. J. Heterocyclic Chem., (2011).     

Efficient nanocoax‐based solar cells

The power conversion efficiency of most thin film solar cells is compromised by competing optical and electronic constraints, wherein a cell must be thick enough to collect light yet thin enough to efficiently extract current. Here, we introduce a nanoscale solar architecture inspired by a well‐known radio technology concept, the coaxial cable, that naturally resolves this “thick–thin” conundrum. Optically thick and elec‐ tronically thin amorphous silicon “nanocoax” cells are in the range of 8% efficiency, higher than any nanostructured thin film solar cell to date. Moreover, the thin nature of the cells reduces the Staebler–Wronski light‐induced degradation effect, a major problem with conventional solar cells of this type. This nanocoax represents a new platform for low cost, high efficiency solar power. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Diffraction characteristics of optical vortex passing through an aperture-iris diaphragm

The diffraction of an optical vortex through an iris diaphragm which is a close approximation to a circular aperture has been investigated. The results are compared with those obtained from the diffraction of a Gaussian beam through the same aperture. In our findings the diffraction of an optical vortex and a Gaussian beam produce ball bearing sort of structure of darkness and brightness. The singularity of the vortex beam is found to be consistent even after the diffraction through the aperture. The presence of singularity at the centre of diffraction pattern of an optical vortex has been confirmed by interferometry. There is a good agreement between the experimental and numerical results. We propose that these results may find various applications in optical trapping experiments.     

Dissociation constants of some derivatives of 5-amino isophthalic acid in mixed solvents

The dissociation constants of some derivatives of 5-amino isophthalic acid have been measured by Calvin Bjerrum pH titration method in DMF-water and DMSO-water (60: 40 v/v) systems at 308.15 K. It is observed that dissociation constant depends on the solvent and substituents group present in the compound.     

Dietary agents in cancer prevention: an immunological perspective(†)

Skin cancer is the most common form of cancer diagnosed in the United States. Exposure to solar ultraviolet (UV) radiations is believed to be the primary cause for skin cancer. Excessive UV radiation can lead to genetic mutations and damage in the skin's cellular DNA that in turn can lead to skin cancer. Lately, chemoprevention by administering naturally occurring non-toxic dietary compounds has proven to be a potential strategy to prevent the occurrence of tumors. Attention has been drawn toward several natural dietary agents such as resveratrol, one of the major components found in grapes, red wines, berries and peanuts, proanthocyanidins from grape seeds, (-)-epigallocatechin-3-gallate from green tea, etc. However, the effect these dietary agents have on the immune system and the immunological mechanisms involved therein are still being explored. In this review, we shall focus on the role of key chemopreventive agents on various immune cells and discuss their potential as antitumor agents with an immunological perspective.     

Synthesis and antimicrobial activity of tetrazolo[1,5-a]quinoline-4-carbonitrile derivatives

Abstract  

A series of new tetrazolo[1,5-a]quinoline-4-carbonitrile derivatives were synthesized for the first time via tetrazolo[1,5-a]quinoline derivatives. Elemental analysis, IR, ¹H NMR, ¹³C NMR, and mass spectral data were used to elucidate the structures of all newly synthesized compounds. In vitro antimicrobial activities of synthesized compounds were investigated against Gram-positive Bacillus subtilis, Gram-negative Escherichia coli, and two fungi, Candida albicans and Aspergillus niger, in comparison with standard drugs. Some of the tested compounds showed significant antimicrobial activity.     

Analgesic and anti-inflammatory activities of the sesquiterpene fraction from Annona reticulata L. bark

The sesquiterpene fraction of Annona reticulata bark was studied by GC/MS. Three major components were identified: copaene (35.40%), patchoulane (13.49%) and 1H-cycloprop(e)azulene (22.77%). The fraction was also screened for its analgesic and anti-inflammatory activities. The sesquiterpene fraction at doses 12.5 and 25?mg?kg?1 and the unsaponified petroleum ether extract at a dose of 50?mg?kg?1 exhibited significant central as well as peripheral analgesic and anti-inflammatory activities. These activities were comparable with the standard drugs used in the respective experiments.     

Synthesis and characterization of Cu2ZnSnS4 thin films by SILAR method

Semiconducting Cu₂ZnSnS₄ (CZTS) material has been receiving a great technological interest in the photovoltaic industry because of its low-cost non-toxic constituents, ideal direct band gap as a absorber layer and high absorption coefficient. CZTS thin films have been successfully deposited onto the fluorine-doped tin oxide/glass (glass/FTO) substrates coated glass substrates using successive ionic layer adsorption and reaction (SILAR) method and investigated for photoelectrochemical conversion (PEC) of light into electricity. The best solar cell sample showed an open-circuit voltage of 390 mV, a short-circuit current density of 636.9 μA/cm², a fill factor of 0.62 and an efficiency of 0.396% under irradiation of 30 mW/cm². Preliminary results obtained for solar cells fabricated with this material are promising.