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Dengale R.A.,Ahmednagar College | Thorat N.M.,Commerce College | Thopate S.R.,Ahmednagar College
Letters in Organic Chemistry | Year: 2016

Background: An expeditious approach has been developed for the synthesis of two distinct classes of benzopyrones viz. flavones and coumarins under solvent-free conditions. L-Ascorbic acid was found to be an effective promoter under microwave irradiation and conventional heating. Various benzo-α-pyrones and benzo-γ-pyrones were synthesized with overall good yields. The present protocol is highly facile and needs no column chromatography for purification and therefore it would serve as an effective and compatible method under both microwave irradiation and conventional heating. Results: The catalytic ability of L-ascorbic acid was investigated for the synthesis of flavones and coumarins. For this purpose, cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanedione and Pechmann coumarin synthesis, reactions were selected. And accordingly, it was observed that one mole of L-ascorbic acid was necessary for the completion of reaction. In all the cases, the desired flavones were smoothly generated with good to excellent yields; indicating its excellent tolerance for various functional groups. However, electron donating groups favors coumarin synthesis under these conditions. All the reaction mixtures were carefully analyzed and NMR indicates high conversions and lack of side products. Conclusion: We have developed L-ascorbic acid-promoted, solvent-free and simple method for the synthesis of benzo-α-pyrones and benzo-γ-pyrone under microwave irradiation as well as conventional heating in good to excellent yields. The notable advantages of this method are solvent-free conditions, inexpensive and efficient eco-friendly promoter, and shorter reaction time and can be carried out under air. This methodology is highly facile and requires no column chromatography for purification. The resulting flavones and coumarins are versatile building blocks in the construction of heterocyclic architectures, dominant in natural products. Further studies of exploiting the efficiency of L-ascorbic acid as a promoter in synthesis of various heterocyclic compounds are in progress. © 2016 Bentham Science Publishers.

Pattan J.S.,Commerce College
Bulgarian Chemical Communications | Year: 2014

Pyrazole and their derivatives are found to have profound biological activity. In the present work some novel substituted pyrazole derivatives were synthesized. Pyrazole are synthesized by treating ethyl bis [methylthio] -2-cyanoacrylate with hydrazide derivatives. The derivatives of pyrazole were prepared by Schiff base reaction.All the synthesized compounds were characterized by IR, 1H-NMR and Elemental Analysis. All the newly synthesized derivatives were evaluated for antimicrobial activity on different micro-organisms (E.coli, S. aureus, A.niger, C. albicans)at the concentration of 200μcg/mL by using cup-plate agar diffusion method. The activity was measured in terms of zone of inhibition and compared with standard drug ciprofloxacin for antibacterial and griseofulvin for antifungal activity. These compounds were also evaluated for antitubercular activity (M. tuberculli) at 25, 50 and 100 μcg/mL concentrations. All the compounds were screened for in-vitro anti-inflammatory activity at different concentration like200 μg/ml, and 300 μg/ml, by inhibition of protein denaturation method. Ibuprofen was used as standard drug. Potent compounds were screened for in vivo anti-inflammatory activity in albino rats at 200 μg/ml concentration to confirm the results. © 2014 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.

Thorat N.M.,Commerce College | Kote S.R.,Ahmednagar College | Thopate S.R.,Ahmednagar College
Letters in Organic Chemistry | Year: 2014

An efficient and eco-friendly synthesis of flavones, promoted by naturally occurring acids, via cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3- propanediones using conventional and microwave heating under solvent-free condition is described. © 2014 Bentham Science Publishers.

Thorat N.M.,Commerce College | Dengale R.A.,Ahmednagar College | Thopate S.R.,Ahmednagar College | Rohokale S.V.,Ahmednagar College
Letters in Organic Chemistry | Year: 2015

Simple and highly efficient approach for the synthesis of γ-Benzopyranones and 3,4-Dihydropyrimidin-2(1H)-ones/thiones using ammonium acetate as a promoter under thermal as well as microwave irradiation using solvent-free conditions has been demonstrated. © 2015 Bentham Science Publishers.

Thorat N.M.,Commerce College | Thopate S.R.,Ahmednagar College
Letters in Organic Chemistry | Year: 2015

Naturally occurring organic acids are reported to be highly efficient promoters for the Biginelli reaction under thermal and microwave irradiation using solvent free conditions. Among the various organic acids used, malic acid was found to be the most effective promoter for Biginelli reaction under above reaction conditions. Present protocol is a simple and eco-friendly route for the synthesis of 3, 4-dihydropyrimidin-2(1H)-ones/thiones. © 2015 Bentham Science Publishers.

Gas sensing properties of NiO-modified ZnO thick films was studied by dipping the thick films of pure ZnO material prepared by screen printing technique in to 0.01 M aqueous solution of Nickel Chloride (NiCl2) for different interval of time (10, 15 and 20 min). The films were dried at 80 °C under IR lamp, followed by firing at 550 °C for 1 h in air ambience. The NiCl2 dispersed on the film surface oxidized in firing process converted in to NiO. The morphological properties of the films were investigated by SEM and the final composition of each film was determined by EDAX analysis. The gas response, selectivity, response and recovery time of the thick films were measured and presented. The gas sensing performance of the films was tested for various gases as function of operating temperature. The NiO-modified ZnO film (15 min dipping) was found to be more sensitive to H2S gas (500 ppm) than pure and other modified films (10, 20 min dipping) with fast response and recovery time. Copyright © 2013 American Scientific Publishers All rights reserved Printed in the United States of America.

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