pp i-iv March 2018
Article ID 0022 March 2018
In the present investigation, a series of bicyclic [2-(2,4-dimethylphenylthio)phenyl] aniline analogues were synthesized and characterized by IR,NMR(1H and 13) and mass spectra.All newly synthesized 15 compounds were inspected for their in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H37Ra in both active and dormant state using an established XTT ReductionMenadione assay (XRMA). The titled compounds exhibited minimum inhibitory concentration (MIC90) ranging from 0.05 to>30 (μg/mL). The potent four compounds were further evaluated in THP-1 infection model where they demonstrated significantantitubercular activity. All the ex vivo active were further evaluated for cytotoxic activity against THP-1, MCK-7 and HeLa cell lines in order to check selectivity index. All compounds were further screened against four different bacteria to assess their selectivity towards MTB. These derivatives could be considered as a precursor structure for further design of antituberculosis agent.
Article ID 0023 March 2018
A series of 3,6-dialkyl-[1,2,4] triazolo[3,4-b][1,3,4]thiadiazole (10) analogues were prepared through multistep synthesis and evaluated them for their antimicrobial and cytotoxic activities. Synthesis of target compounds was carried out using undecenoic acid as starting material, which is the renewable product of castor oil. The key step in the synthesis was formation of triazolo [3,4-b][1,3,4]thiadiazole using various free fatty acids in presence of POCl3. It was observed that the undecenyl based triazolothiadiazole with butyl (6a), hexyl (6b) and lauryl (6f) derivatives exhibited promising antimicrobial activity against the tested strains.Particularly, Compound 6a exhibited the most promising activity with MIC value 3.9 μg/mL against most of the tested strains. It also showed potent minimum bactericidal concentration activity with MIC value 7.8 μg/mL against the tested strains. Cytotoxicity data revealed that most of the tested compounds revealed cytotoxic activity, Compounds 6b, 6d, 6f, 6g, 6h and 6i against SKOV3, 6d, 6e, 6f, 6g, 6h, 6i and 6j against MCF-7 and 6c, 6d, 6e,6g, 6h, 6i and6j against B16–F10 cell lines exhibited significant activities with IC50 values ranged between 13.67 and 18.62 μM. Interestingly, all the compounds were non toxic against Chinese hamster ovary cell (CHO-K1) normal cell
Article ID 0024 March 2018
The imino nitrogen of p-methoxybenzylideneimidazolinone (pMBDI) was protonated using aqueous HClO4 and HCl acid and crystallized in monoclinic crystal system with P21/n space group. Interestingly, the protonated compounds are fluorescent in polar solvents but non-fluorescent in non-polar solvent as well as in the solid state. These results point to the existence of a non-radiative pathway involving the imidazole nitrogen in the quenching of excited states in these compounds.
Article ID 0025 March 2018
Besides the fact that direct synthesis of oxalate-based Mn(II) complexes did not succeed a lot due to the high insolubility of manganese oxalate (MnII(C2O4) · 2H2O), a new 2D polymeric Mn(II) salt has been synthesized by slow evaporation at room temperature and its structure has been determined by single-crystalX-ray diffraction. The structure was solved by direct methods and refined to conventional agreement indices. The crystal structure is built from anionic, two-dimensional, honeycomb networks formed by the oxalatebridged Mn(II) ions, interleaved by 2,6-diaminopyridinium cations that are entrapped between the layers. The interactions between adjacent layers result from the extended network of intermolecular hydrogen bonds created by the mentioned cations and water molecules. The complex has been fully characterized by single crystalX-ray diffraction, FT-IR and UV–Vis spectroscopy, Rietveld refinement, TGA–DSC analysis and magnetic susceptibility. The title compound exhibits antiferromagnetic coupling between Mn(II) centres
Article ID 0026 March 2018
In this work, we have synthesised and crystallographically characterized a mononuclear iron(II) complex, [Fe(phen)3](NO3)2 ·2H2O (1) (phen = 1,10-phenanthroline). Single crystal X-ray diffraction (SXRD) analysis revealed that 1 crystallizes in monoclinic system with P 1− space group. The lattice water molecules in 1 form a water-nitrate cluster, (H2O)2... (NO3)2 through strong H-bonding interaction mediated via iron(II) complex in a unique binding motif and provide additional stability to the compound in the solid state. This iron(II)complex is able to catalyze the cleavage of aromatic C-C linkage of 2,5-dihydroxybenzoic acid (Gentisic acid, GA) in oxygen environment. The iron(II) complex in the presence of two equivalent of triethylamine (Et3N) binds with GA stoichiometrically in acetonitrile medium at 25◦ C. Observation of GA-to-iron LMCT optical bands at 521 and 609 nm supports in situ generated iron-GA adduct in solution. This in situ generated iron-GA adduct reacts with molecular oxygen at the rate, kobs = 6.58×10−3 min−1 in acetonitrile and affords exclusively 2-oxo-4-hydroxy-hepta-3,5-dienedioic acid. The incorporation of both the oxygen atoms of molecular oxygen in the bio-mimicking activity of gentisate-1,2-dioxygenase by this iron(II)-phenanthroline complex remain arare example in scientific literature.
Article ID 0027 March 2018
The catalytic active-phase of reduced Mo species plays a vital role in non-oxidative methane dehydroaromatization (MDA) reaction. Pretreatment effect of one of the gases containing N2, H2 and (90 vol%) CH4 + H2 over 15% Mo-loaded HZSM-5 catalyst has been investigated in the present work. Various spectroscopic investigations viz., XRD, TPR, TPO, XPS, etc., show that the pretreatment of 15% Mo-HZSM-5 catalyst with (90 vol%) CH4 + H2 gas stream exclusively leads to the formation of MoOxCyHzwhich acts as precursor moieties for the formation of highly active metastable fcc (α-MoC1-x) and MoOxCy phases during the induction period. Comparatively, H2 and N2-pretreated catalysts showed major formation of hcp (β-Mo2C) species that are found to be a less-active phase inMDA reaction. The active fcc (α-MoC1-x) phases are immuneto inert coking and assist primary ethylene products formed on carbonized Mo associated Brønsted acid sites to travel in the zeolite channels which is further aromatized over Brønsted acid sites deep inside the channels.XPS analysis of the catalyst shows that α-MoC1-x and β-Mo2C are major catalytic phases that are covered with graphitic carbon and amorphous carbon present on the surface. The active phases α-MoC1-x and MoOxCy,associated with Brønsted acid sites along with the vacant Brønsted acid sites in catalyst pretreated with (90 vol%) CH4 + H2 mixture are responsible for high activity in methane conversion (∼13%), excellent aromatic selectivity (38%), and high stability of the catalyst
Article ID 0028 March 2018
The first total synthesis of Sannanine has been accomplished with an overall 30% yield in a concise manner. The key strategies involve Friedländer quinoline synthesis, demethylation, in situ oxidation and amination process
Article ID 0029 March 2018
Water-mediated, effective, long-range interaction between two hydrophobic surfaces immersed in water is of great importance in natural phenomena.We perform themolecular dynamics simulations to investigate the effect of temperature on the attractive force between two graphene-like hydrophobic surfaces in SPC/Ewater. We systematically calculate the force between two hydrophobic surfaces at different inter-wall separations (d) and subsequently determine the correlation lengths at different temperatures. A significant change in the strength of the attractive hydrophobic force is observed with the variation of temperature. The correlation length of effective hydrophobic force increases on lowering the temperature. We also examine the temperature effects on the behavior of confined water molecules by computing the density and orientational profiles. The analyses of these profiles suggest that the layering of water molecules induced by surfaces decreases with increase in temperature of the system. Critical dewetting distance (dc), where drying transition phenomenon occurs, shifts to the lower value of d upon cooling.
Article ID 0030 March 2018
The Ag-O2 interaction, which is at the center-stage of Ag-catalyzed partial oxidation reactions, is studied with NAP-UPS up to 0.2 mbar O2 pressure between 295 and 550 K. Three temperature regimes were identified for distinct Ag-O2 interaction, which are (a) 295–390 K, where mainly dissociative chemisorption of O2 happens, (b) 390–450 K, where diffusion of O-atoms into the sub-surfaces of Ag is prominent, and (c) >450 K, where metastable oxide forms on polycrystalline Ag surfaces. The work function (WF) of Ag changed from4.95 (<=390 K) to 5.30 eV (390–450 K), and then to 5.7 eV (>=450K) at 0.1mbar O2 pressure. Oxygen population in the sub-surfaces imparts crucial modifications to Ag at 390–450 K; it makes the surface to be electron-deficient that relates to the change in the WF of Ag and facilitates the formation of space charge layer on Ag surface. Oxygen adsorbed on such modified Ag-surfaces is electrophilic in nature, and this appears at a higher binding energy in core level XPS than the chemisorbed oxygen on metallic Ag. This is supported by angle-dependent NAP-XPS studies. The subsurface population of oxygen in Ag no longer persists at >410K when the O2 supply is removed. A high ratio of antibonding/bonding O 2p bands suggests the unique silver-oxygen interaction under the measurement conditions.
Article ID 0031 March 2018
A one-pot protocol involving nitrile-derived amidoxime of 1,5-benzodiazepine to synthesize its novel pyrimidine derivatives using DMAD and DABCO catalyst under microwave conditions has been described. The antibacterial activity of the synthesized compounds was examined against Gram-positive S. aureus and Gram-negative E. coli using broth micro-dilution assay. Low IC50 values for the synthesized compounds indicated their potential as antibacterial agents. Further, field emission scanning electron microscopic study and cell membrane leakage study ascertained that the test compounds have ability to cause cell lysis via bacterial cell membrane rupture and disintegration. In addition, molecular docking studies suggested that test compounds may act through bacterial DHFR inhibition
Volume 132, 2019
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