Ssgm College

Kopargaon, India

Ssgm College

Kopargaon, India
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Shirole G.D.,Asc College | Shirole G.D.,Ssgm College | Shelke S.N.,Ssgm College
Letters in Organic Chemistry | Year: 2016

Background: A green path for the synthesis of 3-aryl-1-phenyl-4-(4,5-diphenyl-1H-imidazol-2-yl)-1H-pyrazole derivatives using [BMIM][BF4] as a catalyst and green methods such as ultrasound and microwave irradiation is discussed in this paper. The titled compounds were obtained by the multi-component condensation of various 3-aryl-1-phenyl-1H-pyrazole-4-carboxaldehydes, benzil and ammonium acetate. One pot synthesis, simple reaction conditions and quantitative yields illustrate the utility of this green approach. Methods: Conventional Reflux Condition: A mixture of 3-aryl-1-phenyl-1H-pyrazole-4-carboxaldehyde 1 (1 mmol), benzil 2 (1 mmol), ammonium acetate 3 (2 mmol) and catalytic amount of [BMIM][BF4] (15 mmol %) was placed in a round bottom flask containing 10 mL of ethanol. The reaction mixture was refluxed for completion. The course of the reaction was monitored by thin layer chromatography. After completion of the reaction, the mixture was poured over crushed ice. Solid imidazole thus obtained was separated by filtration, dried well, and recrystallized by ethanol. Ultrasound Irradiation Method: A mixture of 3-aryl-1-phenyl-1H-pyrazole-4-carboxaldehyde 1 (1 mmol), benzil 2 (1 mmol), ammonium acetate 3 (2 mmol) and catalytic amount of [BMIM][BF4] (15 mmol %) was placed in a round bottom flask containing 10 mL of ethanol. The round bottom flask was placed in an US bath at 50°C for 80-90 min. The course of the reaction was monitored by thin layer chromatography. After completion of the reaction, the mixture was poured into crushed ice, solid imidazoles thus obtained were separated by filtration, dried well, and recrystallized by ethanol. Microwave Irradiation Method: A 10 mL round bottom flask was charged with 3-aryl-1-phenyl-1H-pyrazole-4-carboxaldehyde 1 (1 mmol), benzil 2 (1 mmol), ammonium acetate 3 (2 mmol) and catalytic amount of [BMIM] [BF4] (15 mmol %), and placed under MW irradiation at 240 watts for 7-9 min. The course of the reaction was monitored by thin layer chromatography. After completion of the reaction, the mixture was poured over crushed ice, the solid imidazole thus obtained was separated by filtration, dried well, and recrystallized by ethanol. Results: The 3-aryl-1-phenyl-4-(4,5-diphenyl-1H-imidazol-2-yl)-1H-pyrazole derivatives 4a-i (Scheme 1, Table 2) were synthesized by using [BMIM] [BF4] as a catalyst with good yields under reflux in ethanol (68-70%), US irradiation in ethanol (76-80%) and MW irradiation (80-86%) without solvent. All these methods provided good results with IL [BMIM][BF4]. However, the MW and US irradiation methods give good yield in a short period of time with 3-aryl-1-phenyl-1H-pyrazole-4-carboxaldehyde 1 containing a variety of substituents, whereas the conventional reflux condition gives lower yields and takes longer time as compared with MW and US irradiation. The structures of the synthesized compounds have been confirmed on the basis of spectroscopic techniques such as FTIR, HRMS, LCMS, 1H and 13C NMR. Conclusion: In conclusion, we have synthesized differently substituted imidazoles using [BMIM][BF4] as a catalyst under MW and US irradiation via MC condensation strategy. Under the conventional reflux conditions, we get a lower yield in a longer time, while US and MW assisted synthesis gave better results. Comparatively IL [BMIM][BF4] with US and MW irradiation protocol provides several advantages such as improved reaction speed, shorter reaction times, superior yields and a significant contribution towards sustainability. © 2016 Bentham Science Publishers.

Vidule R.R.,Ssgm College | Shirodkar S.G.,Ns B College
Journal of Chemical and Pharmaceutical Research | Year: 2013

Synthesis of substituted 3-arylidene-2-methylpyrazolo [5,1-b]quinazolin-9(3H)-ones [4a-t] is attempted by the condensation of aromatic aldehydes [3a-d] with 2-methylpyrazolo [5,1-b]quinazolin-9(4H)-ones [2a-e] in the presence of piperdine. 2a-e were obtained by azeotropic distillation of 3-methyl-1H-pyrazol-5(4H)-one and 1Hbenzo [d] [1,3]oxazine-2,4-diones [1a-e]. The structures of synthesized compounds are confirmed by IR and 1HNMR, 13CNMR and mass spectral studies. Further, they were screened in vitro for antibacterial activity against Escherichia coli and Salmonella typhi. Antifungal activity is evaluated against Aspergillus niger and Penicillium chrysogenum using Paper disc diffusion method. Some of the compounds were found to exhibit promising antibacterial and antifungal activities.

Shelke S.,Ssgm College | Mhaske G.,Ssgm College | Gadakh S.,Ssgm College | Gill C.,Dr Bam University
Bioorganic and Medicinal Chemistry Letters | Year: 2010

A series of novel fluorine-containing triazoles 3, thiadiazoles 4, and oxadiazoles 5 were synthesized from thiosemicarbazides 2. These reactions were carried out by green technique such as ultrasonication and microwave. All products have been characterized by IR, 1H NMR, and Mass spectral study and screened for their antimicrobial activity. © 2010 Elsevier Ltd. All rights reserved.

Shirole G.D.,Asc College | Shirole G.D.,Ssgm College | Kadnor V.A.,Acs College | Tambe A.S.,Asc College | Shelke S.N.,Ssgm College
Research on Chemical Intermediates | Year: 2016

Abstract: We present a facile and environmentally benign protocol for synthesis of variously substituted imidazole derivatives via multicomponent condensation of benzil, primary aromatic amine, substituted 1,3-diphenyl-1H-pyrazole-4-carbaldehyde, and ammonium acetate in presence of 1-butyl-3-methyl-1-imidazolium tetrafluoroborate [BMIM][BF4] as catalyst under conventional reflux as well as microwave irradiation condition. The one-pot synthesis, facile solvent-free condition, and good isolated yield illustrate the utility of this green approach. The structural features are derived using analytical tools including fourier transform infrared (FTIR), Liquid chromatography-mass spectrometry (LCMS), and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Graphical Abstract: [Figure not available: see fulltext.] © 2016 Springer Science+Business Media Dordrecht

Shelke S.N.,Ssgm College | Mhaske G.R.,Ssgm College | Bonifacio V.D.B.,New University of Lisbon | Gawande M.B.,New University of Lisbon
Bioorganic and Medicinal Chemistry Letters | Year: 2012

A new series of fluorinated pyrazoles, 4a-e, were synthesized in good to excellent overall yields (65-82%) from the corresponding chalcones, 3a-e, by ultrasonic irradiation. The newly synthesized compounds were characterized and screened for their in vitro anti-bacterial, anti-fungal, and anti-tubercular activities against Mycobacterium tuberculosis H37Rv. © 2012 Elsevier Ltd. All rights reserved.

Kalkar C.D.,University of Pune | Nikumbh A.B.,Ssgm College | Kulkarni G.K.,Ssgm College
Oriental Journal of Chemistry | Year: 2011

Reduction of nitrate takes place when the stored energy in the form of colour centres is released during dissolution of g-irradiated crystalline potassium fluoride In aqueous potassium nitrate solution. Various parameters like dose, amount and storage time of irradiated potassium fluoride which control the yield of nitrite have been studied. Similarly, the effect of concentration of potassium nitrate has been investigated. The energy transfer parameter has been determined as the ratio of G/NO 2 - obtained by the addition of irradiated crystalline potassium fluoride on the basis of reduction of nitrate.

Gawande M.B.,Palacky University | Shelke S.N.,Ssgm College | Zboril R.,Palacky University | Varma R.S.,U.S. Environmental Protection Agency
Accounts of Chemical Research | Year: 2014

ConspectusThe magic of microwave (MW) heating technique, termed the Bunsen burner of the 21st century, has emerged as a valuable alternative in the synthesis of organic compounds, polymers, inorganic materials, and nanomaterials. Important innovations in MW-assisted chemistry now enable chemists to prepare catalytic materials or nanomaterials and desired organic molecules, selectively, in almost quantitative yields and with greater precision than using conventional heating. By controlling the specific MW parameters (temperature, pressure, and ramping of temperature) and choice of solvents, researchers can now move into the next generation of advanced nanomaterial design and development.Microwave-assisted chemical reactions are now well-established practices in the laboratory setting although some controversy lingers as to how MW irradiation is able to enhance or influence the outcome of chemical reactions. Much of the discussion has focused on whether the observed effects can, in all instances, be rationalized by purely thermal Arrhenius-based phenomena (thermal microwave effects), that is, the importance of the rapid heating and high bulk reaction temperatures that are achievable using MW dielectric heating in sealed reaction vessels, or whether these observations can be explained by so-called "nonthermal" or "specific microwave" effects.In recent years, innovative and significant advances have occurred in MW hardware development to help delineate MW effects, especially the use of silicon carbide (SiC) reaction vessels and the accurate measurement of temperature using fiber optic (FO) temperature probes. SiC reactors appear to be good alternatives to MW transparent borosilicate glass, because of their high microwave absorptivity, and as such they serve as valuable tools to demystify the claimed magical MW effects. This enables one to evaluate the influence of the electromagnetic field on the specific chemical reactions, under truly identical conventional heating conditions, wherein temperature is measured accurately by fiber optic (FO) probe.This Account describes the current status of MW-assisted synthesis highlighting the introduction of various prototypes of equipment, classes of organic reactions pursued using nanomaterials, and the synthesis of unique and multifunctional nanomaterials; the ensuing nanomaterials possess zero-dimensional to three-dimensional shapes, such as spherical, hexagonal, nanoprisms, star shapes, and nanorods. The synthesis of well-defined nanomaterials and nanocatalysts is an integral part of nanotechnology and catalysis science, because it is imperative to control their size, shape, and compositional engineering for unique deployment in the field of nanocatalysis and organic synthesis.MW-assisted methods have been employed for the convenient and reproducible synthesis of well-defined noble and transition core-shell metallic nanoparticles with tunable shell thicknesses. Some of the distinctive attributes of MW-selective heating in the synthesis and applications of magnetic nanocatalysts in organic synthesis under benign reaction conditions are highlighted. Sustainable nanomaterials and their applications in benign media are an ideal blend for the development of greener methodologies in organic synthesis; MW heating provides superb value to the overall sustainable process development via process intensification including the flow systems. © 2014 American Chemical Society.

Jadhav R.K.,Ssgm College | Nikumbh A.B.,Ssgm College | Karale B.K.,Radhabai Kale Mahila Mahavidyalaya
Oriental Journal of Chemistry | Year: 2015

A series of 3-Formylchromone 1 was reacted with 1-(4-(4-fluorophenyl)thiazol-2-yl)hydrazine 2 to get (1-(4-(4-fluorophenyl)thiazol-2-yl)-1H-pyrazol-4-yl)(2-hydroxyphenyl) methanone 3 which on reaction with hydroxylamine hydrochloride given methanone oxime 4 and 4 on treatment with POCl3formed 2-(1-(4-(4-fluorophenyl)thiazol-2-yl)-1H-pyrazol-4-yl)benzo[d]oxazole 5. The structures of synthesized compounds were confirmed by spectral analysis further they were screened for their biological activity.

Shelke S.N.,Ssgm College | Bankar S.R.,Ssgm College | Mhaske G.R.,Ssgm College | Kadam S.S.,Ssgm College | And 8 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2014

An efficient and benign protocol is reported for the synthesis of medicinally important pyrazole derivatives, 4-methoxyaniline, and Ullmann-type condensation reaction using magnetically separable and reusable magnetite-supported copper (nanocat-Fe-CuO) nanoparticles under mild conditions. Nanoparticles with average size of 20-30 nm have been synthesized using simple impregnation techniques in aqueous medium from readily available inexpensive starting materials and were recycled six times without loss in catalytic activity. © 2014 American Chemical Society.

Gawande M.B.,New University of Lisbon | Shelke S.N.,SSGM College | Branco P.S.,New University of Lisbon | Rathi A.,Jubilant Chemsys Ltd. | Pandey R.K.,Marquette University
Applied Organometallic Chemistry | Year: 2012

An environmentally benign method for O-tert-Boc protection of alcohols and phenols catalyzed by MgO-ZrO 2 nanoparticles under solvent-free conditions is described. A variety of phenols, alcohols (aliphatic and aromatic) were converted to corresponding O-tert-Boc products in good to excellent yield (50-95%). The present protocol is expedient, simple, and efficient under solvent-free conditions. The MgO-ZrO 2 Nps are easily prepared from inexpensive precursors, and are reusable, recyclable and chemoselective. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.

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