• Vijay Kumar

      Articles written in Journal of Chemical Sciences

    • Melting of ice cubes under controlled conditions

      R Pratap Singh Vijay Kumar Upadhyay

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      Weight variations with time during the melting of suspended ice cubes under controlled conditions at various temperatures ranging from 10–45°C have been experimentally studied. The melting data have been used to determine certain parameters leading to the calculation of complete melting time, thickness of the water film on ice surface and the temperature at the interface of air and water films.

    • Controlled release of 5-flurouracil from biomedical polyurethanes

      Reddy Seetharamareddy Harisha Kallappa Mahadevappa Hosamani Rangappa Sangappa Keri Namdev Shelke Vijay Kumar Wadi Tejaraj M Aminabhavi

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      Novel biodegradable aliphatic poly(ether-urethane)s (PEUs) based on pluronic F-68 (PLF68) and castor oil were synthesized by the solution polymerization technique. These polymers were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic spectroscopy (1HNMR) and gel permeation chromatography (GPC) to confirm the PEU formation and the molecular weight. Moderate molecular weight PEUs were obtained and converted into microspheres by solvent evaporation method to study the controlled release (CR) characteristics for 5-flurouracil (5-FU). PLF-68 acts as amphiphilic filler, which enhances the release of a hydrophobic drug such as 5-FU. Sizes of the microspheres as measured by laser light scattering technique ranged between 15 and 42 𝜇m. An increase in the size of particles was observed with increasing molar ratio of PLF-68 with respect to castor oil. The percentage encapsulation efficiency varied between 71 and 98. Surface morphology of the microspheres as studied by scanning electron microscopy (SEM) revealed the spherical nature of the particles with wrinkles on their surfaces. The release of 5-FU through the microspheres was investigated in pH 7.4-phosphate buffer. An increase in release rate was observed with increasing molar ratio of PLF68 with respect to castor oil.

    • Heterocyclyl linked anilines and benzaldehydes as precursors for biologically significant new chemical entities

      Raman K Verma Vijay Kumar Prithwish Ghosh Lalit K Wadhwa

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      Benzylidene and benzyl thiazolidinediones, oxazolidinediones, isoxazolidinediones and their acyclic analogs like alpha alkylthio/alkoxy phenylpropanoic acids, beta-keto esters and tyrosine-based compounds possess broad therapeutic potential in general and as Peroxisome Proliferator Activated Receptors (PPARs) agonists in particular in the management of hyperglycemia and hyperlipidaemia for the treatment of Type 2 Diabetes (T2D). We have synthesised and characterized some novel and suitably substituted heterocyclyl linked benzaldehydes and anilines, which can be easily and very readily derivatized to all the above mentioned classes to generate new chemical entities of broader biological significance. Synthesis of their benzylidene thiazolidinedione and diethyl malonate and also benzyl diethyl malonate and alpha-bromoesters derivatives is reported in some of the cases in the present work.

    • Design, synthesis and computational validation of novel benzimidazole/indole-based PPARα and PPARγ partial agonists

      Raman K Verma Prithwish Ghosh Vijay Kumar Lalit K Wadhwa

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      The design and synthesis of benzimidazolyl and indolyl linked 𝛼-alkoxy phenylpropanoic acid derivatives and the 𝛽-keto ester analogues in an effort to develop novel peroxisome proliferator activated receptors ligands expected to exhibit PPAR𝛼 and PPAR𝛾 partial agonism in the management of hyperglycemia and hyperlipidemia for the treatment of type 2 diabetes is reported. Computational validation of the designed molecules through activity prediction and docking studies showed expected results.

    • Influence of silyloxy substitution on the photochromic properties of diarylbenzo- and naphthopyrans


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      Diarylbenzopyrans and their annulated derivatives are a class of photochromic compounds, which have been extensively investigated for photochromism. In fact, some naphthopyrans are employed industrially in ophthalmic lens applications. Photoirradiation of 2,2-diphenylbenzopyran leads to the formation of coloredo-quinonoid intermediates. The latter revert too rapidly to allow their observation only at low temperatures (173–263 K). Annulation and other strategies are exploited to observe the colored o-quinonoid intermediates that persist for a few minutes at room temperature. We have examined photochromism of a set of silyloxysubstituted 2,2-diphenylbenzo- and naphthopyrans to explore how the mesomeric effects transmitted by the strongly e-donating silyloxy group substituted in the ring and at phenyl groups manifest in the spectrokineticproperties of their photogenerated colored o-quinonoid intermediates. We show that silyloxy substitution in the benzopyran ring leads to remarkable stabilization of the colored intermediates to enable their persistence at 283 K for a few minutes. In contrast, similar substitution in the C2-phenyl rings destabilizes the colored intermediates.

    • Highly active zinc oxide-supported lithium oxide catalyst for solventfree Knoevenagel condensation


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      Li2O/ZnO catalyst was prepared by wet impregnation method and characterized by XRD, SEM,EDX, FTIR, BET surface area and UV-Vis diffuse reflectance spectroscopy. This study revealed a decrease inaverage particle size and change in the shape of the particles when Li2O was supported on ZnO. The activityof ZnO-supported lithium oxide catalyst was tested for Knoevenagel condensation of a variety of aromaticaldehydes with malononitrile and ethyl cyanoacetate at room temperature under solvent-free condition. Thereaction was completed in a very short time with yields above 90% and the catalyst presented excellentreusability without any loss in the activity.

      Novel lithium oxide supported on zinc oxide catalyst was synthesized and analysed using several techniques. Lithium doping decreases the particle size, and band gap energy and increases the surface area and basic properties of the catalyst. The olefin derivatives were obtained in a very short reaction time under the solvent free condition at room temperature in a green protocol.

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