Kinetics and mechanism of the oxidation of substituted benzaldehydes by benzyltrimethylammonium chlorobromate

The oxidation of 35 monosubstituted benzaldehydes by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both benzaldehyde and BTMACB. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of benzyltrimethylammonium chloride or potassium bromide on the reaction rate. The oxidation of [(2)H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes were correlated in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes was correlated with the tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect, whereas the oxidation of ortho-and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of eta suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric hindrance by the ortho substituents.     

One‐pot solvent and catalyst‐free synthesis of functionalized 1,8‐naphthyridines and quinolines by microwave irradiation

A series of functionalized, aryl substituted naphthyridines and quinolines has been synthesized by microwave‐assisted one‐pot two‐component synthesis under solvent‐free conditions in good yields by the reaction of a variety of aryl or heteroaryl amines and aryl vinyl ketones. A combinatorial type approach for a one‐step microwave reaction has been developed where a ring‐closing condensation is followed by a spontaneous aromatization to afford the functionalized aryl substituted 1,8‐naphthyridines and quinolines.     

Sensitivity analysis of the newsvendor model

Quality of decisions in inventory management models depends on the accuracy of parameter estimates used for decision making. In many situations, error in decision making is unavoidable. In such cases, sensitivity analysis is necessary for better implementation of the model. Though the newsvendor model is one of the most researched inventory models, little is known about its robustness. In this paper, we perform sensitivity analysis of the classical newsvendor model. Conditions for symmetry/skewness of cost deviation (i.e., deviation of expected demand–supply mismatch cost from its minimum) have been identified. These conditions are closely linked with symmetry/skewness of the demand density function. A lower bound of cost deviation is established for symmetric unimodal demand distributions. Based on demonstrations of the lower bound, we found the newsvendor model to be sensitive to sub-optimal ordering decisions, more sensitive than the economic order quantity model. Order quantity deviation (i.e., deviation of order quantity from its optimum) is explored briefly. We found the magnitude of order quantity deviation to be comparable with that of parameter estimation error. Mean demand is identified as the most influential parameter in deciding order quantity deviation.     

A scheme to observe universal breathing mode and Berezinskii–Kosterlitz–Thouless phase transition in a two-dimensional photon gas

A system of two-dimensional photon gas has recently been realized experimentally. We show that this setup can be used to observe a universal breathing mode of photon gas and a modification in the experimental setup would open up a possibility of observing the Berezinskii–Kosterlitz–Thouless (BKT) phase transition in such a system. Furthermore, the universal jump in the superfluid density of light in the output channel can be used as an unambiguous signature for the experimental verification of the BKT transition.     

An in vitro and in vivo study of a novel zinc complex, zinc N-(2-hydroxyacetophenone)glycinate to overcome multidrug resistance in cancer

Multiple drug resistance (MDR) remains a major clinical challenge for cancer treatment. P-glycoprotein is the major contributor and they exceed their role in the chemotherapy resistance of most of the malignancies. Attempts in several preclinical and clinical studies to reverse the MDR phenomenon by using MDR modulators have not yet generated promising results. In the present study, a co-ordination complex of zinc viz., Zn N-(2-hydroxyacetophenone)glycinate (ZnNG) has been synthesized, characterized and its antitumour activity was tested in vitro against drug sensitive and resistant human T-lymphoblastic leukemic cell lines (CCRF/CEM and CEM/ADR5000 respectively) and in vivo against Ehrlich ascites carcinoma (EAC) implanted in female Swiss albino mice. To evaluate the cytotoxic potential of ZnNG, we used sensitive CCRF/CEM and drug resistant CEM/ADR 5000 cell lines in vitro. Moreover, ZnNG also has the potential ability to reverse the multidrug resistance phenotype in drug resistant CEM/ADR 5000 cell line and induces apoptosis in combination with vinblastine. ZnNG remarkably increases the life span of Swiss albino mice bearing sensitive and doxorubicin resistant subline of EAC in presence and in absence of doxorubicin. In addition, intraperitoneal application of ZnNG in mice does not show any systemic toxicity in preliminary trials in normal mice. To conclude, a novel metal chelate of zinc viz., ZnNG, may be a promising therapeutic agent against sensitive as well as drug resistant cancers.     

Quasinormal modes of a charged spherical black hole with scalar hair for scalar and Dirac perturbations

The quasinormal modes of charged and uncharged massive scalar fields and also of charged Dirac fields against the background of a charged spherical black hole endowed with a scalar hair have been investigated. Special emphasis has been given to the case where negative scalar charge dominates over the electric charge of the black hole which mimics an Einstein-Rosen bridge. Except for the complete monotonic behaviour of the damping (imaginary part of the quasinormal frequency) against the charge of the black hole as opposed to the existence of a peak for the pure Reissner-Nordström case, the qualitative behaviour does not appreciably change due to the presence of scalar hair.     

Pd-Catalyzed Regioselective Domino C−C Bond Formation to Access N-Fused Benzimidazo-Indolo-Isoquinoline Heterocycles

Regioselective synthesis of N-fused benzimidazo-indolo-isoquinoline heterocycles via Pd-catalyzed domino coupling reaction of 1-(1-methyl-1H-indol-2-yl)-1H-benzimidazoles and aryl halides was developed. This one pot methodology proceeded via a five-member carbopalladacycle intermediate and provided direct and facile route to access structurally complex polyheterocycles in moderate to good yields. These unique hybrid molecules resembled structural similarity with naturally isolated alkaloids. Notably, the present domino process occurred through activation of three C−H bonds and the simultaneous formation of two new C−C bonds in one-shot. These molecules exhibited strong solid and solution phase fluorescence and their emission spectra in both the medium are reported here.