A one-pot multicomponent Biginelli reaction for the preparation of novel pyrimidinthione derivatives as antimicrobial agents

A convenient synthesis of pyrimidinthiones was carried out in presence of thiourea and easily available catalyst sulfamic acid ( 2a-t) . One-pot Biginelli reaction is very important due to the use of simple and readily available chemicals, less reaction time, economically friendly, and furnishing good yield. Structures of the synthesized compounds are characterized by spectral techniques like IR, ¹H-NMR, ¹³C-NMR, and LC–MS. Synthesized compounds were studied for their antimicrobial activity against several strains of bacteria (E. coli, P. aeruginosa, and S. aureus, S. pyogenes) and fungi (C. albicans, A. niger, and A. clavatus) using serial dilution method.     

Synthesis,biological evaluation,and molecular docking study of pyridine clubbed 1,3,4-oxadiazoles as potential antituberculars

A series of pyridine clubbed 1,3,4-oxadiazole derivatives were efficiently synthesized, characterized by standard spectral techniques and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H₃₇Ra and Mycobacterium bovis BCG in active and dormant state using an established methods. Compounds 5a, 5m, and 5t were identified as the most active compounds against MTB. Molecular docking was performed against MTB enoyl-ACP (CoA) reductase (FabI/ENR/InhA) enzyme to predict the binding modes and affinity. The theoretical predictions from molecular docking could establish a link between the observed biological activity and the binding affinity shedding light into specific bonded and non-bonded interactions influencing the activity. The active compounds were studied for cytotoxicity against three cell lines and were found to be non-cytotoxic. Specificity of these compounds was checked by screening them for their antibacterial activity against four bacterial strains.     

Study of mesomorphism dependence on molecular flexibility of an azoester series containing a napthyl unit

A novel azoester homologous series of liquid crystalline (LC) compounds: RO?C₆H₄-COO?C₁₀H₆-N:N-C₆H₄?OC₄H₉(n) without lateral substitution has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC substances with reference to tailed-end group. The novel homologous series consists of 13 homologs (C₁ to C₁₈) whose nematogenic and smectogenic mesomorphism commences enantiotropically from C₆ and C₁₂ members of the series, respectively. The C₁₂–C₁₈ homologs are smectogenic and C₆–C₁₈ are nematogenic, of which C₁₂–C₁₈ homologs are smectogenic plus nematogenic. The C₁–C₅ homologs are nonmesogenic. Transition temperatures and the textures of the homologs were determined and identified by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren and that of the smectic phase are of the type A or C. Transition curves Cr-M/I, Sm-N and N-I of a phase diagram behaved in normal manner except N-I transition temperature of C₁₀ homolog which deviated by 9°C–10°C from normal behavior. N-I transition curve exhibited odd-even effect. Analytical, spectral, and thermal data confirms the molecular structures of homologs. Thermal stability for smectic and nematic are 115.5°C and 138.5°C, respectively whose corresponding mesophaselengths are varied from 10.0°C to 16.0°C and 13.0°C to 24.0°C, respectively. Group efficiency order for smectic and nematic are derived from comparative study of structurally similar analogous series; as smectic: ?OC₄H₉ (n) > ?CH₃ > ?H; Nematic: ?H > ?OC₄H₉ (n) > ?CH₃     

Synthesis, characterization, DNA binding and cytotoxicity studies of moxifloxacinato complexes

Five metal complexes of the third-generation quinolone antibacterial agent moxifloxacin with Cu(II), Fe(III), Mn(II), Ni(II) and VO(II) have been synthesized and characterized by physicochemical and spectroscopic techniques. In these complexes, moxifloxacin acts as a bidentate deprotonated ligand bound to the metal through ketone and carboxylate oxygens. The interactions between the metal complexes and calf thymus DNA have been studied by UV?CVis, circular dichroism and cyclic voltammetry. Fluorescence competitive binding studies with ethidium bromide (EB) demonstrate the ability of the complexes to displace the EB bound to DNA. The cytotoxicities of the complexes have been evaluated on A549 cells by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. [Cu(MFL)₂(H₂O)₂] shows the highest anticancer potency. The apoptosis-inducing activity was assessed by acridine orange/ethidium bromide staining assay.     

Study of a new homologous series of liquid crystals: Isopropyl-p-(p/-n-alkoxy cinnamoyloxy) cinnamates

A new homologous series: isopropyl-p-[p^/-n-alkoxy cinnamoyloxy] cinnamates was synthesized and studied with a view to understanding and establishing the relation between liquid crystal property and molecular structure. Twelve homologues were synthesized. Methyl to butyl homologues are not liquid crystals, while pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tetradecyl, and hexadecyl derivatives are enantiotropic liquid crystal in nature with nematogenic character. Smectogenic character is totally absent. A phase diagram is obtained by plotting a graph of transition temperatures versus number of carbon atoms is n-alkyl chain of left n-alkoxy terminal end group. Solid-isotropic or solid-nematic transition curve rises steeply from methyl to propyl derivatives and falls to pentyl homologue through butyl homologue, and follows a zigzag path of rising and falling values as the series is ascended. Nematic–isotropic transition curve shows descending tendency as series is ascended in a normal manner with exhibition of odd-even effect. Smectic mesophase does not appear even in the monotropic condition. Phase transition temperatures are determined by hot stage polarizing microscope. Analytical data support the structure of molecules. Texture of nematic mesophase is of threaded type. Mesomorphic properties are compared with structurally similar homologous series.     

High scale parity invariance as a solution to the SUSY CP problem and an explanation of small ε′/ε

It is shown that if the supersymmetric Standard Model (MSSM) emerges as the low energy limit of a high scale left-right symmetric gauge structure, the number of uncontrollable CP violating phases of MSSM are drastically reduced. In particular it guarantees the vanishing of the dangerous phases that were at the root of the so called SUSY CP problem. Such a symmetric gauge structure is independently motivated by the smallness of neutrino masses that arise via seesaw mechanism automatic in the theory. The minimal version of this theory also provides an explanation of the smallness of ε′/ε as a consequence of the high scale parity invariance. This talk is based on work done in collaboration with K S Babu and B Dutta.     

FAR-RED INDUCED, LONG-LIVED AFTERGLOW FROM PHOTOSYNTHETIC CELLS. SIZE OF AFTERGLOW UNIT AND PATHS OF ENERGY ACCUMULATION AND DISSIPATION

Abstract— –Small amounts of N -methyl phenazonium methosulphate (PMS) added to a suspension of Chlorella pyrenoidosa accelerate the emission of the long-lived far-red induced afterglow without greatly changing the amount of light emitted. The effect is noticeable in dilute suspensions at a PMS concentration of 10^-9 M. The concept of afterglow unit is introduced and defined as that part of the sample in which the rate of energy reemission can be controlled by a single molecule of PMS. The number of chlorophyll molecules per afterglow unit is about 10⁵. It is possible that the afterglow unit is identical to the thylakoid.
The rate constant for the final first order decay phase of afterglow at room temperature is about 0.7 min^-1 without PMS and about 3 times larger for a unit with one PMS molecule.
Diuron (DCMU) lowers the rate of afterglow decay. Desaspidin on the other hand decreases the amount of light emitted without affecting the decay rate. Carbonylcyanide- m -chlorophenyl hydrazone (CCCP) decreases the afterglow over the whole time-range and increases the decay rate. A kinetic model is developed to account for the results.     

A new process of multicomponent Povarov reaction–aerobic dehydrogenation: synthesis of polysubstituted quinolines

A new domino process of three-component Povarov reaction and aerobic dehydrogenation was developed toward the synthesis of polysubstituted quinolines. 2,4-Disubstituted-8-nitroquinolines, which are important precursors for the synthesis of antimalarial primaquine drug-like molecules, were prepared conveniently by this method in moderate to good yields. Brönsted acid (HClO₄)-modified montmorillonite was found to be a crucial catalyst in promoting the procedure.     

Synthesis,spectral, thermal and crystallographic investigations on oxovanadium(IV) and manganese(III) complexes derived from heterocyclic β-diketone and 2-amino ethanol

Novel mononuclear oxovanadium(IV) and manganese(III) complexes [VO(L¹)₂·H₂O] (1); [VO(L²)₂·H₂O] (2); [VO(L³)₂·H₂O] (3); [Mn(L¹)₂]ClO₄·H₂O (4); [Mn(L²)₂] ClO₄·H₂O (5); [Mn(L³)₂]ClO₄·H₂O (6) were prepared by condensation of 1 mol of VOSO₄·5H₂O or Mn(OAc)₃· 2H₂O with 2 mol of ligand HL¹, HL² or HL³ (where HL¹ = 4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2- phenyl-2,4-dihydro-pyrazol-3-one; HL²=4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2-p-tolyl-2,4-dihydro-pyrazol-3-one; HL³=4-{4-[(2-hydroxy-ethyl-amino)-methyl]-3-methyl-5-oxo-4,5-dihydropyrazol-1-yl} benzene sulfonic acid). The resulting complexes were characterized by elemental analyses, molar conductance, magnetic and decomposition temperature measurements, electron spin resonance, FAB mass, IR and electronic spectral studies. From TGA, DTA and DSC, the thermal behaviour and degradation kinetic were studied. Electronic spectra and magnetic susceptibility measurements indicate distorted octahedral stereochemistry of oxovanadium(IV) complexes and regular octahedral stereochemistry of manganese(III) complexes. Hamiltonian and bonding parameters found from ESR spectra indicate the metal ligand bonding is partial covalent. The X-ray single crystal determination of one of the representative ligand was carried out which suggests existence of amine-one tautomeric form in the solid state. The ¹H-NMR spectra support the existence of imine-ol form in solution state. The LC-MS studies sustain the¹H-NMR result. The electronic structure of the same representative ligand was optimized using 6-311G basis set at HF level ab initio studies to predict the coordinating atoms of the ligand.