Faculty Publications

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Author: search.filters.author.Bhat, S.I.Has files: No

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    Condensation of malononitrile with salicylaldehydes and o-aminobenzaldehydes revisited: Solvent and catalyst free synthesis of 4H-chromenes and quinolines
    (Royal Society of Chemistry, 2012) Bhat, S.I.; Choudhury, A.R.; Trivedi, D.R.
    The reaction of malononitrile with salicylaldehyde under solvent and catalyst free conditions was re-investigated using mechanochemical mixing, thermal heating and a direct crystallization process. The resulting condensation product by all three types of molecular activation, was found to be (2-amino-3-cyano-4H-chromene-4-yl)malononitrile, which is not the previously reported benzofuran-2-carbonitrile. The structure of the resulting chromene derivative was confirmed by FT-IR, MS, 1H, 13C NMR and single crystal and powder X-ray diffraction. The reaction pathway under neat conditions (mechanochemical mixing) at ambient temperature was monitored by IR spectral measurements. The versatility of the current green protocol was examined through the reaction of eleven derivatives of o-hydroxybenzaldehyde with malononitrile to obtain 2-amino-3-cyano-4H-chromene derivatives. In addition, malononitrile was further reacted with o-aminobenzaldehydes under neat conditions to yield quinoline derivatives. © 2012 The Royal Society of Chemistry.
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    Fast and efficient synthesis of N-substituted ?-aminobutyric acids by grinding at room temperature
    (Springer Verlag, 2013) Bhat, S.I.; Trivedi, D.R.
    Green chemistry is gaining increasing interest due to the growing awareness of the chemical community for sustainable development. Green chemistry solutions include synthesis without solvent and catalyst because many solvents and catalysts are toxic and expensive. Herein, we report the solvent and catalyst free method for the synthesis of N-substituted derivatives of ?-aminobutyric acid by direct aza-Michael addition of amines to crotonic acid. The protocol involves simple mixing or grinding the reactants at room temperature. The ?-amino acid derivatives were obtained in 82-100 % yield with a short reaction time without any tedious workup procedures. Our findings thus reveal a promising alternative to previously used procedures. © 2013 Springer-Verlag Berlin Heidelberg.
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    A catalyst- and solvent-free three-component reaction for the regioselective one-pot access to polyfunctionalized pyrroles
    (2013) Bhat, S.I.; Trivedi, D.R.
    A facile method for the regioselective synthesis of tetrasubstituted pyrroles, from readily accessible 1,3-dicarbonyls, benzoin derivatives and ammonium acetate, has been developed. The one-pot three-component reactions were performed to afford tetrasubstituted pyrroles under solvent- and catalyst-free conditions. © 2013 Elsevier Ltd. All rights reserved.
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    A highly efficient and green cascade synthesis of 3-methyl-substituted-4- hydroxy-1-methyl-quinolin-2(1H)-ones under solvent- and catalyst-free conditions
    (2014) Bhat, S.I.; Trivedi, D.R.
    An expeditious and green protocol for the synthesis of 3,3?- methanediylbis(4-hydroxy-1-methylquinolin-2(1H)-one) (MDBHQ) derivatives and 3-((2-amino-6-oxocyclohex-1-enyl)methyl)-4-hydroxy-1-methylquinolin-2(1H)-one (AOCHQ) derivatives has been developed via a cascade Knoevenagel-Michael reaction. The products were obtained in high yield under neat reaction conditions without any work-up or chromatographic purification. The generality and functional tolerance of this environmentally benign protocol is demonstrated. © 2014 The Royal Society of Chemistry.
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    An Efficient Three-component, One-pot Synthesis of Quinazolines under Solvent-free and Catalyst-free Condition
    (HeteroCorporation support@jhetchem.com, 2015) Bhat, S.I.; Das, U.K.; Trivedi, D.R.
    An efficient green protocol for the synthesis of quinazolines in the absence of solvent and catalyst has been developed. 2,4-Disubstituted quinazolines have been synthesized from three-component one-pot reactions of 2-aminoaryl ketones, orthoesters, and ammonium acetate. The present method has advantages of operational simplicity, substrate generality, clean reaction, high yields (76-94%), and moderate reaction time. The plausible mechanism of the reaction has been proposed based on the spectral characterization and single crystal X-ray analysis of isolated intermediate. © 2014 HeteroCorporation.
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    Electrochemical Studies of Zn-Ni-Fe Alloy Coatings for Better Corrosion Resistance Applications
    (Springer, 2022) Bhat, R.S.; Munjunatha, K.B.; Bhat, S.I.; Venkatakrishna, K.; Hegde, A.C.
    Anti-corrosive alloy coatings are a valuable solution to the protection of low carbon steel structures/equipment against corrosion. The Zn-Ni-Fe coatings have been deposited galvanostatically on low carbon steel from an acid chloride bath. Sulfanilic acid and gelatin were used as additives for the homogeneity of the deposit. The Hull cell method has been used to optimize both bath constituents and plating conditions. The corrosion behavior of the coating films was examined with potentiodynamic polarization and the electrochemical impedance spectroscopy methods. The effects of current density, pH, and temperature on deposit properties like hardness, thickness, and corrosion rates were examined. The electrochemical characteristics of the Zn-Ni-Fe have been studied by the cyclic voltammetry technique. The morphology of the deposit was investigated with scanning electron microscopy and the surface roughness of the coating film was analyzed by atomic force microscopy. The Ni and Fe contents in the deposit were analyzed by colorimetric technique and cross-checked with energy-dispersive x-ray analysis. The capacitive reactance at the interface is attributed to the excellent corrosion resistance at optimal current density (40 mA cm−2) as indicated by the Nyquist plot with large polarization resistance. Furthermore, the positive slope of Mott-Schottky revealed that the semiconductor film at the interface is n-type. The results show that a new Zn-Ni-Fe alloy coating film exhibits better corrosion resistance properties and can be executed in industrial applications such as machine tools, bolts, and nuts in the automobile for corrosion protection, etc. © 2022, ASM International.