- Stereoselective synthesis of trans-3-functionalized-4-pyrazolo[5,1-b]thiazole-3-carboxylate substituted β-lactams: Potential synthons for diverse biologically active agents
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An efficient protocol for the stereoselective synthesis of pyrazolo[5,1-b]thiazole-3-carboxylate tethered β-lactam conjugates 8a–j from novel pyrazolo [5,1-b]thiazole-3-carboxylate substituted Schiff’s bases 6a–f is reported here. The reaction between various ketene precursors and novel Schiff’s bases 6a–f afforded exclusive formation of trans-β-lactams 8a–j. The substrate scope of this approach was investigated extensively by varying different groups (R, Z). All the novel compounds were characterized using various spectroscopic techniques, such as FT-IR, 1H NMR, 13C NMR, elemental analysis, 13C NMR (DEPT-135), and mass spectrometry in representative cases. Single crystal X-ray crystallographic study of trans-ethyl 7-(1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin-2-yl)-6-methyl-2-(methylthio)pyrazolo[5,1-b]thiazole-3-carboxylate 8a has confirmed the molecular structure and the stereochemical outcome. To the best of our knowledge, the synthesis of such types of Schiff’s bases and β-lactam conjugates has not been reported so far.
- Berry, Shiwani,Bari, Shamsher S.,Yadav, Pooja,Garg, Ankita,Khullar, Sadhika,Mandal, Sanjay K.,Bhalla, Aman
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- Ligand based design and synthesis of pyrazole based derivatives as selective COX-2 inhibitors
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The design and synthesis of novel pyrazole based derivatives has been carried out using the ligand based approach like pharmacophore and QSAR modelling of reported pyrazoles from the available literature to investigate the chemical features that are essential for the design of selective and potent COX-2 inhibitors. Both pharmacophore and QSAR models with good statistical parameters were selected for the design of the lead molecule. Also by exploiting the chemical structures of selective and marketed COX-2 inhibitors, celecoxib and SC-558 were used in designing the molecules which are used in the treatment of inflammation and related disorders. The therapeutic action of the Non-Steroidal Anti-inflammatory Agents (NSAIDs) is based primarily on the COX-2 inhibition. With this background we have synthesized some azomethine derivatives of 3-methyl-1-substituted-4-phenyl-6-[{(1E)-phenylmethylene}amino]-1,4-dihydro pyrano[2,3-c]pyrazole-5-carbonitrile 6(a-o) and were characterized by 1HNMR, 13CNMR and Mass spectral techniques. All the synthesized pyrazole derivatives were tested for in vitro membrane stability property in both COX-1 & COX-2 inhibition studies and in vivo anti-inflammatory activity by carrageenan induced rat paw edema model. Among them, compound 6k showed very good activity by in vivo anti-inflammatory activity with 0.8575 mmol/kg as ED50. Similarly compounds 6m, 6o, 6i and 6h exhibited comparable anti-inflammatory activity to standard drugs. Also the active compounds were further screened for ulcerogenic activity and were found be safer with less ulcer index compared to the marketed drugs like aspirin, ibuprofen and celecoxib.
- Murahari, Manikanta,Mahajan, Vivek,Neeladri, Sreenivasulu,Kumar, Maushmi S.,Mayur
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- Synthesis and Evaluation of Pyrazole Derivatives as Potent Antinemic Agents
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Pyrazole derivatives were synthesized by bromination of pyrazole, followed by N-alkylation of 4-bromopyrazole. The synthesized derivatives were characterized by microanalytical data and IR and 1H and 13C NMR spectra and were evaluated for their nematicidal activity against the root knot nematode Meloidogyne incognita. The compounds were screened for their egg hatch inhibition and mortality potential, and they showed significant nematicidal activity as compared to the control. 1H-Pyrazol-5(4H)-one was found to be most effective in egg hatch inhibition, and 4-bromopyrazole was found to be most effective in juvenile mortality.
- Dhillon, N. K.,Jain, N.,Kaur, G.,Utreja, D.
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- Fused Heterocyclic Compounds as Potent Indoleamine-2,3-dioxygenase 1 Inhibitors
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Uncontrolled metabolism of l-tryptophan (l-Trp) in the immune system has been recognized as a critical cellular process in immune tolerance. Indoleamine 2,3-dioxygenase 1 (IDO1) enzyme plays an important role in the metabolism of a local l-Trp through the kynurenine pathway in the immune systems. In this regard, IDO1 has emerged as a therapeutic target for the treatment of diseases that are associated with immune suppression like chronic infections, cancer, and others. In this study, we synthesized a series of pyridopyrimidine, pyrazolopyranopyrimidine, and dipyrazolopyran derivatives. Further lead optimizations directed to the identification of potent compounds, 4j and 4l (IC50 = 260 and 151 nM, respectively). These compounds also exhibited IDO1 inhibitory activities in the low nanomolar range in MDA-MB-231 cells with very low cytotoxicity. Stronger selectivity for the IDO1 enzyme (>300-fold) over tryptophan 2,3-dioxygenase (TDO) enzyme was also observed for these compounds. Hence, these fused heterocyclic compounds are attractive candidates for the advanced study of IDO1-dependent cellular function and immunotherapeutic applications.
- Panda, Subhankar,Roy, Ashalata,Deka, Suman Jyoti,Trivedi, Vishal,Manna, Debasis
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- SBA-Pr-SO3H-catalyzed synthesis of bispyrazole compounds as anti-bacterial agents and inhibitors of phosphorylated RET tyrosine kinase
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Pyrazolone was prepared through the reaction of ethyl acetoacetate and hydrazine hydrate in EtOH at room temperature. Then, bispyrazole derivatives, as attractive biologically active compounds, were synthesized by reacting two equivalents of prepared pyrazolone and one equivalent of aldehyde in the presence of SBA-Pr-SO3H under solvent-free condition at 120?°C. The reaction time was short (3–6?min), while the products’ yield was high (85–97%). Discovery Studio 2.5 (Accelrys Inc, San Diego, CA, USA) was employed to dock the compounds to protein. Molecular docking (GOLD method) studies suggested that pyrazoles bind efficiently to RET kinase. Next, biological activities of the bispyrazoles were tested against some Gram-positive and Gram-negative bacteria and for antifungal activity via the disc-diffusion method. All compounds showed no significant anti-bacterial activities, but two of them showed good activities against Candida albicans. Graphical abstract: [Figure not available: see fulltext.]
- Mohammadi Ziarani, Ghodsi,Saidian, Fatemeh,Gholamzadeh, Parisa,Badiei, Alireza,Ghasemi, Jahan B.,Aghaee, Elham,Abolhasani Soorki, Ali
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- Synthesis of 6-amino-4-aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5- carbonitriles by heterogeneous reusable catalysts
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A new, efficient and environmentally benign protocol for the one-pot, four-component synthesis of 1,4-dihydropyrano[2,3-c]pyrazoles by reaction of hydrazine monohydrate, ethyl acetoacetate, arylaldehydes and malononitrile in the presence of a green catalytic amount of P2O5/SiO 2, H3PO4/Al2O3, cellulose sulfuric acid and starch sulfuric acid is described. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.
- Shaterian, Hamid Reza,Kangani, Mehrnoosh
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- A new, convenient and expeditious synthesis of 4-alkyl-5-methyl-1H-pyrazol-3-ols in water through a multicomponent reaction
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A new, simple and efficient synthesis of 4-alkyl-5-methyl-1H-pyrazol-3-ols in water by a two-pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aldehyde and ketone in presence K2CO3as the catalyst is described. Use of water as the reaction medium, operational simplicity, mild reaction conditions, application of a cost-effective, nontoxic and easily available catalyst with auto-tandem catalysis, wide substrate scope, easy workup and purification process make the protocol highly attractive.
- Kalita, Subarna Jyoti,Bayan, Rajarshi,Devi, Jutika,Brahma, Sanfaori,Mecadon, Hormi,Deka, Dibakar Chandra
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- Polyethylene glycol-promoted synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives in water
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Synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives were achieved using polyethylene glycol (PEG-400) as promoting reaction medium in water under catalyst-free conditions at reflux and room temperature, respectively. The structure of pyrimido[1,2-a]benzimidazole was confirmed using 1H NMR, 13C NMR, DEPT, and HMBC experiments. The promising points for the present methodology are efficiency, generality, high yield, short reaction time, cleaner reaction profile, ease of product isolation, simplicity, potential of recycling reaction medium, and finally agreement with green chemistry protocols.
- Survase, Dattatray,Bandgar, Babasaheb,Helavi, Vasant
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- Heterocyclic derivatives of sugars: The formation of 1-glycosyl-3-methylpyrazol-5-ones from hydrazones
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Conditions to effect the conversion of monosaccharide and disaccharide hydrazones to 1-glycosyl-3-methylpyrazol-5-ones were examined. The sugar pyrazolone derivatives were sensitive to oxidation, but high yields were achieved with 2,2,2-trifluoroethyl acetoacetate in mildly acidic solution. Azo coupling of the pyrazolones produced highly coloured azopyrazolone derivatives that prevented further degradation, and these may prove useful labels for chromatographic analysis of carbohydrates. (C) 2000 Elsevier Science Ltd.
- Kett, Warren C,Batley, Michael,Redmond, John W
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- Synthesis of Pyranopyrazoles Using Magnetically Recyclable Heterogeneous Iron Oxide-silica Core-shell Nanocatalyst
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The Fe3O4@SiO2 core-shell nanocatalyst were prepared and efficiently used for four-component coupling reaction of aromatic aldehydes, malononitrile, ethyl acetoacetate and hydrazine hydrate in water/ethanol mixture. Various aromatic aldehydes possessing electron-withdrawing and electron-donating groups in different positions on the ring were successfully transformed to substituted pyranopyrazoles in high yields in short time. The nanocatalyst was easily recovered, and reused five times without significant loss in cata- lytic activity and performance. The structure, size and morphology of the nanosized catalyst were studied by various techniques such as Fourier transform infrared spectroscopy, powder X-ray diffraction, dynamic light scattering and transmission electron microscopy.
- Soleimani, Ebrahim,Jafarzadeh, Mohammad,Norouzi, Parastoo,Dayou, Jedol,Sipaut, Coswald Stephen,Mansa, Rachel Fran,Saei, Parisa
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- Synthesis, characterization and molecular docking studies of substituted 4-coumarinylpyrano[2,3-c]pyrazole derivatives as potent antibacterial and anti-inflammatory agents
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A green, eco-friendly and efficient protocol has been developed and synthesized a series of coumarin based pyrano[2,3-c]pyrazole derivatives (3) by multi-component reaction (MCR). Unexpected 3-coumarinyl-3-pyrazolylpropanoic acids (4) have been isolated by the reaction of compound (3) in acidic conditions. Further, intramolecular cyclization of compounds (4) leads to C4[sbnd]C4chromons (9) and these compounds were screened for their biological activities using array of techniques. Most of the compounds exhibited promising antibacterial activity, in particular Gram-positive bacteria. The anti-inflammatory assay was evaluated against protein denaturation as well as HRBC membrane stabilization methods and compounds exhibit excellent anti-inflammatory activity in both methods. Molecular docking study has been performed for all the synthesized compounds with S.?aureus dihydropteroate synthetase (DHPS) and results obtained are quite promising.
- Chougala, Bahubali M.,Samundeeswari,Holiyachi, Megharaja,Shastri, Lokesh A.,Dodamani, Suneel,Jalalpure, Sunil,Dixit, Sheshagiri R.,Joshi, Shrinivas D.,Sunagar, Vinay A.
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- Expeditious synthesis of functionalized tricyclic 4-spiro pyrano[2,3-c]pyrazoles in aqueous medium using dodecylbenzenesulphonic acid as a Br?nsted acid-surfactant-combined catalyst
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An efficient, three-component, one-pot synthesis of highly functionalized tricyclic 4-spiro pyrano[2,3-c]pyrazoles incorporating medicinally privileged heterocyclic moieties has been developed, which also involves the tandem Knoevenagel/Michael addition reaction followed by dehydrative cyclization of pyrazolone derivatives, cyclic 1,3-diketones and cyclic ketones, catalyzed by dodecylbenzenesulphonic acid (DBSA) as a Br?nsted acid-surfactant-combined catalyst in aqueous medium. The catalyst is found to be highly competent in accelerating this reaction that results in a considerable short reaction time, alleviating the need for high thermal energy. Wide substrate scope, high to excellent product yield, operational simplicity, absence of any hazardous organic solvent, mild reaction conditions, a simple work up procedure and easily available starting materials are the salient features of this protocol.
- Mukherjee, Prasun,Paul, Sanjay,Das, Asish R.
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- Nanoalkalinecellulose immobilized on magnetic nanoparticles as a green catalyst for the synthesis of tetrahydrodipyrazolopyridines and mechanistic insights under base catalysis
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The cotton-derived nanoalkalinecellulose (NAC) flocculated on the Fe3O4-nanoparticles was analytically characterized as Fe3O4@NAC. With the 1:5.7 weight ratio for organic:inorganic and the base-capacity equal to 7.5?mmol HO?/g, the Fe3O4@NAC represented a catalytic advantage in the room-temperature one-pot pseudo-multicomponent synthesis of tetra-hydrodipyrazolopyridines (THDPPs) in water. Mechanistic monitoring supported no requisite to acid/base catalyst in the first phase for rapid formation of intermediate 3-methylpyrazolone (A) by Knorr reaction of the ethylacetoacetate with hydrazine hydrate in water at room temperature. Alternatively, Fe3O4@NAC showed catalytic roles in the further reaction phases in synthesis of THDPPs from the A. Excellent base capacity, hydrogen-bonding performance, and stability due to no significant activity loss and leaching after five reaction cycles are advantages of this organometallic catalyst.
- Tamaddon, Fatemeh,Ahmadi-AhmadAbadi, Ehsan,Kargar, Hossein
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- Microwave domino diastereoselective synthesis of novel trans-4,5-dihydro-1H-furo[2,3-c]pyrazoles using pyridinium salts in an aqueous medium
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Novel fused 4,5-dihydro-1H-furo[2,3-c]pyrazole derivatives containing both biologically active pyrazole and furan templates are synthesised by a one-pot two-step four-component domino reaction involving hydrazine hydrate, a β-keto ester, an aromatic aldehyde and a pyridinium salt catalysed by DABCO with high diastereoselectivity in H2O under microwave irradiation. To minimise the formation of byproducts, the hydrazine hydrate and ethyl acetoacetate were first irradiated until a pyrazolone was formed. Next, the aryl aldehyde, the pyridinium salt and DABCO were added and the reaction could be completed in good to excellent yields. The salient features of this eco-friendly methodology are highlighted by its short reaction time (10–12 min), high yields, high atom-economy, efficiency of producing five new bonds (2C–C, C=N, C–N and one C–O), two new rings and two stereocentres in a single operation, absence of any tedious work-up or purification and avoidance of separation of intermediates.
- Yazdani-Elah-Abadi, Afshin,Morekian, Reza,Simin, Nasim,Lashkari, Mojtaba
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- Synthesis of 4,5-dihydropyrazolyl-2H-indenediones by aldol condensation of ninhydrin with 1H-pyrazol-5-ol
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A simple and efficient procedure for the synthesis of 2-hydroxy-2-(5-hydroxy-1H-pyrazol-4-yl)-2H-indene-1,3-dione derivatives, proceeding via aldol condensation between ninhydrin and various 3-alkyl-1H-pyrazol-5-ols is described. The syntheses were carried out in ethanol at room temperature and proceeded with short reaction times to give the products with high yields.
- Soleimania, Ebrahim,Hariri, Mina,Rostamzadeh, Arman,Ghorbani, Somayeh
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- A novel method for the synthesis of pyrazolo[5,1-b]thiazole
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By a new tandem reaction, in which ethyl 1-pyrazolacetate reacted with carbon disulfide and iodomethane, pyrazolo[5,1-b]thiazole was synthesized. This was an easy method for the synthesis of this type of heterocyles.
- Wang, Zhongwen,Ren, Jun,Li, Zhengming
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- Synthesis and cytotoxic evaluation of some substituted pyrazole zirconium (IV) complexes and their biological assay
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Pyrazole and their derivatives are found to have intense biological efficiency. In the present work some substituted pyrazole derivatives were synthesized and used as ligands (4-[2-vinylthiophene]-3-methyl pyrozolin-5(4H) - one (L1), 4-[4-chloro benzylidine]-3-methyl pyrozolin-5(4H) - one (L2) and 4-[4-dimethylnitro benzylidine]-3-methylpyrozolin-5(4H) - one (L3)) to prepare the zirconium (IV) complexes. The synthesized ligands and their complexes were obtained as colored powdered materials and were characterized using magnetic measurements, melting point, molar conductance, infrared, electronic, 1HNMR, mass spectra and thermogravimetric analyses. All of the tested compounds showed good microbial activity against pathogenic microorganisms. The tested compounds exhibited considerable antitumor activity and cytotoxic specificity towards human colon carcinoma cell line (HCT-116).
- El-Shwiniy, Walaa H.,Shehab, Wesam S.,Mohamed, Soha F.,Ibrahium, Hend G.
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- Concentrated solar radiation-assisted one-pot/multicomponent synthesis of pyranopyrazole derivatives under neat condition
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Concentrated solar radiation (CSR)-assisted synthesis of pyranopyrazole derivatives under solvent and catalyst-free condition has been reported in the present protocol. One-pot multicomponent synthesis from aromatic/heteroaldehyde, ethyl acetoacetate, malononitrile, and hydrazine hydrate leads to the final desired compounds in a good yield. This operationally simple methodology has several advantages such as green and clean reaction profile, simple workup and purification procedures, extremely short reaction time, atom efficiency, and being economical. The current energy-efficient method saves almost 98% of energy as compared to the conventional method. Graphical abstract: [Figure not available: see fulltext.]
- Gadkari, Yatin U.,Hatvate, Navnath T.,Telvekar, Vikas N.
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- Facile, one-pot, four-component synthesis of a new series of imidazo[1,2-a]pyridines in presence of TPAB in EtOH under reflux conditions
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Abstract: A convenient, regioselective, novel, and elegant one-pot, four-component reaction was designed for synthesis of a series of new of imidazo[1,2-a]pyridines using aryl glyoxal monohydrates, ethyl acetoacetate, hydrazine hydrate, and 2-aminopyridine in presence of tetrapropylammonium bromide under reflux in EtOH as solvent. The main advantages of this protocol include the availability and low cost of the starting materials, short reaction time, convenient operation, easy workup process, highly facile operation, nonhazardous byproducts, and high yield (82–94%). Graphical abstract: [Figure not available: see fulltext.].
- Etivand, Nasser,Khalafy, Jabbar,Poursattar Marjani, Ahmad
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- Facile synthesis of novel α-methylene-pyrazole-carboxylate substituted imines and trans-β-lactams: Versatile synthons for diverse heterocyclic molecules
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A simple, facile, and high yielding stereoselective approach for the integration of α-methylene-pyrazole-carboxylates at the β-lactam nucleus is described. These monocyclic β-lactams have been synthesized by treatment of 2-phenoxy/benzylthio/phenylthio ethanoic acids or acetoxyacetyl chloride/phthalimidoacetyl chloride 5a–e with novel α-methylene-pyrazole-carboxylate imines 4a–c using Et3N and POCl3 in refluxing toluene. All of the newly synthesized α-methylene-pyrazole carboxylate imines 4a–c and their β-lactam derivatives 6a–h have been fully characterized by spectroscopic techniques such as FTIR, NMR (1H, 13C, and 13C DEPT-135), 2D-NMR (COSY and HSQC), and elemental analyses (CHN). The cycloaddition reaction was found to be highly stereoselective leading to the exclusive formation of trans-β-lactams 6a–h and trans configuration was assigned with respect to coupling constant values of C3-H and C4-H. The novel β-lactams 6a–h bearing α-methylene-pyrazole-carboxylate ring system will serve as useful synthons for highly functionalized acids, acetohydrazides/pyrazolones, alcohols, pyrazole carboxamides, peptides, and promising biologically active agents.
- Hundal, Qudrat,Berry, Shiwani,Narula, Dipika,Bari, Shamsher S.,Bhalla, Aman
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- Antitubercular 2-Pyrazolylpyrimidinones: Structure-Activity Relationship and Mode-of-Action Studies
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Phenotypic screening of a Medicines for Malaria Venture compound library against Mycobacterium tuberculosis (Mtb) identified a cluster of pan-active 2-pyrazolylpyrimidinones. The biology triage of these actives using various tool strains of Mtb suggested a novel mechanism of action. The compounds were bactericidal against replicating Mtb and retained potency against clinical isolates of Mtb. Although selected MmpL3 mutant strains of Mtb showed resistance to these compounds, there was no shift in the minimum inhibitory concentration (MIC) against a mmpL3 hypomorph, suggesting mutations in MmpL3 as a possible resistance mechanism for the compounds but not necessarily as the target. RNA transcriptional profiling and the checkerboard board 2D-MIC assay in the presence of varying concentrations of ferrous salt indicated perturbation of the Fe-homeostasis by the compounds. Structure-activity relationship studies identified potent compounds with good physicochemical properties and in vitro microsomal metabolic stability with moderate selectivity over cytotoxicity against mammalian cell lines.
- Soares De Melo, Candice,Singh, Vinayak,Myrick, Alissa,Simelane, Sandile B.,Taylor, Dale,Brunschwig, Christel,Lawrence, Nina,Schnappinger, Dirk,Engelhart, Curtis A.,Kumar, Anuradha,Parish, Tanya,Su, Qin,Myers, Timothy G.,Boshoff, Helena I. M.,Barry, Clifton E.,Sirgel, Frederick A.,Van Helden, Paul D.,Buchanan, Kirsteen I.,Bayliss, Tracy,Green, Simon R.,Ray, Peter C.,Wyatt, Paul G.,Basarab, Gregory S.,Eyermann, Charles J.,Chibale, Kelly,Ghorpade, Sandeep R.
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supporting information
p. 719 - 740
(2021/02/03)
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- Preparation of GO/SiO2/PEA as a new solid base catalyst for the green synthesis of some spirooxindole derivatives
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Efficient and green one pot multi component synthesis of some spirooxindole derivatives in the presence of graphene oxide functionalized with 2-(1-piperazinyl) ethylamine (GO/SiO2/PEA) as a solid base catalyst was studied. GO/SiO2/PEA has been obtained through a two step reaction and characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), thermo gravimetric analysis (TGA), Raman spectroscopy and X-ray diffraction (XRD). Green reaction conditions, short reaction times, reusable catalyst and a high to excellent yield of products are some of the advantageous of the presented method.
- Moradi, Leila,Toorbaf, Mahla
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p. 21840 - 21850
(2021/07/01)
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- Identification of novel scaffold using ligand and structure based approach targeting shikimate kinase
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Tuberculosis (TB) remains a major global health problem. It causes ill-health among millions of people each year and rank as the second leading cause of death from an infectious disease worldwide, after the human immunodeficiency virus (HIV). Shikimate kinase is one of the major enzymes targeted for TB. Most approaches to overcome TB were based on synthesis and screening of a known compounds to obtain a few representatives with desired potency. In this study, we have applied a virtual screening approach which combines ligand- and structure-based approaches to screen a large library of compounds as a starting point for the identification of new scaffolds for the development of shikimate kinase inhibitors. The combined approach has identified 2 new scaffolds as potential inhibitors of shikimate kinase. To prove the approach, few of the molecules and their derivatives, a total of 17 compounds, were synthesized. The compounds were tested for biological activity and shows moderate activity against shikimate kinase. The shikimate kinase enzyme inhibition study reveals that the compounds showed inhibition (IC50) at concentrations of 50 μg/mL (Compounds 21, 22, 24, 25, 26, 27, 30, 32, 34) and 25 μg/mL (14, 19, 23, 31, 33).
- Rahul Reddy,Krishnasamy, Sivakumar Kullampalayam,Kathiravan
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- Green and efficient synthesis of fluorescent bis(Pyrazolyl)methanes in choline chloride/urea deep eutectic solvent
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A series of pyrazole-based heteroaromatic compounds were synthesized by the reaction of 3-methyl-5-pyrazolone and aromatic aldehydes in Choline chloride/urea DES as a green solvent. This simple and green procedure has advantages such as easy operation, short reaction times, efficient yields, low cost and minimum use of hazardous solvents and catalysts. The structure of compounds was determined by IR,1H and13C NMR spectra, and the crystal structure of 4a was confirmed using X-ray crystallographic analysis. The optical properties of Pyrazole derivatives 4a-g have also been studied with UV/vis and fluorescence spectroscopy. All of these pyrazole-containing heteroaromatic compounds displayed maximum emission peak from 340 to 360 nm.
- Beiranvand, Masoumeh,Mohammad-Rezaei, Rahim,Naderi, Soheila,Zonouz, Adeleh Moshtaghi
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p. 548 - 554
(2020/07/17)
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- Alpha-Casein: an efficient, green, novel, and eco-friendly catalyst for one-pot multi-component synthesis of bis (pyrazol-5-ols), dihydro-pyrano[2,3-c]pyrazoles and spiropyranopyrazoles in an environmentally benign manner
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For the first time, alpha-Casein was used as an efficient and eco-friendly catalyst for an effective and facile preparation of dihydropyranopyrazoles and spiropyranopyrazoles. The synthesis of bis (pyrazol-5-ols) derivatives was developed via one-pot, pseudo-five-component condensation, and the target dihydropyrano[2,3-c]pyrazoles and spiropyranopyrazoles were prepared by one-pot four-component reaction. This new method of employing alpha-Casein, which is a green, recyclable, non-toxic and commercially available catalyst, offers advantages such as mild condition, short reaction times, easy work-up, no need for column chromatography, and high yields of the products which make it more economic than other environmentally synthetic protocols.
- Milani, Jalili,Maghsoodlou, Malek Taher,Hazeri, Nourallah,Nassiri, Mahmoud
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p. 1651 - 1664
(2019/04/25)
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- A convenient route toward one-pot multicomponent synthesis of spirochromenes and pyranopyrazoles accelerated via quinolinic acid
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In the present work, the catalytic activity of quinolinic acid (QUIN) was studied for the synthesis of spirochromene and pyranopyrazole derivatives from readily available materials. The salient features of these one-pot multicomponent protocols are the clean reaction profile, easy isolation of products, no chromatographic separation techniques, high efficiency, short reaction time, and high yield of products plus using QUIN as a new, inexpensive, commercially available, and efficient organocatalyst.
- Oudi, Maryam,Sanchooli Tazeh, Kazem,Hazeri, Nourallah,Fatahpour, Maryam,Ahmadi, Raheleh
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p. 1721 - 1728
(2019/06/08)
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- A concise route for the one-pot multi-component synthesis of 4,6-disubstituted 2-aminopyridine-3-carbonitriles and pyranopyrazoles using cobalt (II) nitrate hexahydrate as catalyst
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Three facile and efficient routes for one-pot, cobalt (II) nitrate hexahydrate catalyzed multi-component synthesis of 2-amino-3-cyanopyridine and pyranopyrazole derivatives have been developed. The present protocols offer the products in good yields from the simple and readily available starting materials. The other salient features of these protocols are operational simplicity, easy isolation of product without the need of column chromatographic purification, and the use of cobalt (II) nitrate hexahydrate as an efficient catalyst.
- Pejman, Hamed,Hazeri, Nourallah,Fatahpour, Maryam,Faroughi Niya, Homayoun
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p. 241 - 247
(2019/07/31)
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- Synthesis of Pyrazolo-[4?,3?:5,6]pyrido[2,3-d]pyrimidine-diones Catalyzed by a Nano-sized Surface-Grafted Neodymium Complex of the Tungstosilicate via Multicomponent Reaction
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An inorganic–organic hybrid based on lanthanide clusters and Keggin type polyoxometalates (POMs) (Na[Nd (pydc-OH)(H2O)4]3}[SiW12O40]) was used the first time as trinuclear catalyst for one pot synthesis of pyrazolo[4??,3?:5,6]pyrido[2,3-d]pyrimidine-diones, via two different four and five-component reactions involving hydrazine hydrate, ethyl acetoacetate, aryl aldehydes, and 6-amino-1,3-dimethyl uracil or barbituric acid with ammonium acetate as alternative materials in green condition. To evaluate potential application of the as-made hybrid in adsorption and separation processes, nitrogen adsorption was performed at 77?K through simulation study. The hybrid catalyst was further characterized via powder X-ray diffraction (PXRD) at room temperature which indicated the good phase purity of the catalyst. The results show that the catalytic activity of the hybrid catalyst has increased relative to each parent component due to the special interaction between Keggin anions and pydc-OH ligands.
- Daraie, Mansoureh,Heravi, Majid M.,Mirzaei, Masoud,Lotfian, Nahid
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- A new method for making pyrazole or pyrimidinone
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The invention relates to the use of an amine compound in a method for producing a fluorinated or non-fluorinated 5- or 6-membered heterocyclic compound (preferably pyrazole or pyrimidinone) containingtwo nitrogen atoms in a ring system. The invention also relates to a method for producing a pyrazole or pyrimidinone, which may be fluorinated or may not be fluorinated (non-fluorinated). Each of thefluorinated pyrazole or fluorinated pyrimidinone is a very important structural unit for pharmaceutical and agricultural applications. For example, fungicides are strongly dependent on bifenapram, fluoxastrobin, flubenazolid, fluoxastrobin, pyraclostrobin, and pyracloprid, each with this fluorinated pyrazole as a key structural unit, and benflufenazole respectively, or diflufenacil and chlorfensulfazone (dimethachlor).
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Paragraph 0302-0305
(2019/11/28)
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- 3-methyl-4-substituted benzylidene pyrazol-5-ones: Synthesis, evaluation of antinociceptive activities and in silico studies
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A series of 3-methyl-4-substituted benzylidene pyrazol-5-ones were subjected to molecular docking studies using targets involved in nociception such as COX-2, TRPV1, P2X3 and glutamate to explore the structural features necessary for interactions with the active site of amino acids in various biological targets. Molecular docking studies showed that the introduction of electron releasing groups on benzylidene ring seem to enhance the binding affinity of pyrazolones. Compounds M2 (4-hydroxy) and M8 (3,4-dimethoxy) showed good binding affinity for TRPV1 and P2X3 receptors, whereas compound M9 (3,4,5-trimethoxy) was found to be favorable for COX-2 and glutamate receptors. These compounds were synthesized and evaluated using capsaicin, ATP and glutamate induced nociception to study the effect of title compounds on TRPV1, purinergic and glutamate receptors, respectively at a dose of 150 mg/kg body weight. Compounds M6 (3,4-dichlro) and M8 (3, 4-dimethoxy) displayed good antinociceptive activity in TRPV1 and ATP induced nociception models whereas, compound M9 (3, 4, 5-trimethoxy) exhibited promising activity in glutamate-induced nociception. Some of the synthesized compounds bearing unsubstituted 4-hydroxy-2,3-dimethoxy and 4-dimethylamino benzylidene ring (M1-M4) have been earlier reported for their antinociceptive activity in acetic acid induced writhing and tail immersion methods. The results of the present study implicated that the compounds possessing 4-hydroxy and 4-dimethylamino groups showed good antinociceptive activity in all the models. The results might be useful to design and develop pyrazolones as potential antinociceptive agents.
- Swapna,Begum, Shaheen,Begum, Arifa,Bharathi,Sujatha
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p. 2107 - 2115
(2018/08/09)
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- Screening, synthesis, crystal structure, and molecular basis of 6-amino-4-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles as novel AKR1C3 inhibitors
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AKR1C3 is a promising therapeutic target for castration-resistant prostate cancer. Herein, an evaluation of in-house library discovered substituted pyranopyrazole as a novel scaffold for AKR1C3 inhibitors. Preliminary SAR exploration identified its derivative 19d as the most promising compound with an IC50 of 0.160 μM among the 23 synthesized molecules. Crystal structure studies revealed that the binding mode of the pyranopyrazole scaffold is different from the current inhibitors. Hydroxyl, methoxy and nitro group at the C4-phenyl substituent together anchor the inhibitor to the oxyanion site, while the core of the scaffold dramatically enlarges but partially occupies the SP pockets with abundant hydrogen bond interactions. Strikingly, the inhibitor undergoes a conformational change to fit AKR1C3 and its homologous protein AKR1C1. Our results suggested that conformational changes of the receptor and the inhibitor should both be considered during the rational design of selective AKR1C3 inhibitors. Detailed binding features obtained from molecular dynamics simulations helped to finally elucidate the molecular basis of 6-amino-4-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles as AKR1C3 inhibitors, which would facilitate the future rational inhibitor design and structural optimization.
- Zheng, Xuehua,Jiang, Zan,Li, Xiaolin,Zhang, Chen,Li, Zhe,Wu, Yinuo,Wang, Xinhua,Zhang, Chao,Luo, Hai-bin,Xu, Jun,Wu, Deyan
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supporting information
p. 5934 - 5943
(2018/11/23)
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- An efficient protocol for the one-pot four-component synthesis of 6-amino-1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile derivatives using starch solution as a reaction media
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An efficient, high-yielding and rapid protocol has been developed for the synthesis of 6-amino-l,4-dihydropyrano [2,3-c]pyrazol-5-carbonitrile derivatives through four-component, one-pot cyclocondensation reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes and malononitrile utilizing starch solution as a highly efficient homogenous catalyst. The use of a nontoxic, reusable and biodegradable catalyst is one of the superior advantagesof this protocol. Short reaction times, mild conditions, excellent product yields, simple work-up procedure and non use of toxic organic solvents are added advantages of this procedure.
- Vekariya, Rajesh H.,Patel, Kinjal D.,Patel, Hitesh D.
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p. 576 - 582
(2019/05/21)
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- A 3 - methyl -5 - pyrazolone synthetic method
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The invention belongs to the preparation of organic fine chemicals technical field, in particular to a 3 - methyl - 5 - pyrazolone synthetic method. The 3 - methyl - 5 - pyrazolone of the synthetic method for methanol as the solvent, in order to acetyl methyl acetate and hydrazine as raw material in the reaction under reflux conditions, the end of the reaction, after-treatment of the 3 - methyl - 5 - pyrazolone. The invention of 3 - methyl - 5 - pyrazolone of the synthetic method improves the reaction efficiency, shortens the reaction time, thereby reducing the cost and improving the purity of the product. In addition, the reaction mother liquor can be recycled many times, the protection of the environment, the utilization rate of the materials is improved.
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Paragraph 0042-0083
(2018/07/30)
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- Synthesis and biological evaluation of dihydropyrano-[2,3-c]pyrazoles as a new class of PPAR? partial agonists
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Peroxisome proliferator-activated receptor ? (PPAR?) is a well-known target for thiazolidinedione antidiabetic drugs. In this paper, we present the synthesis and biological evaluation of a series of dihydropyrano[2,3-c]pyrazole derivatives as a novel family of PPAR? partial agonists. Two analogues were found to display high affinity for PPAR? with potencies in the micro molar range. Both of these hits were selective against PPAR?, since no activity was measured when tested against PPARα, PPAR? and RXRα. In addition, a novel modelling approach based on multiple individual flexible alignments was developed for the identification of ligand binding interactions in PPAR?. In combination with cell-based transactivation experiments, the flexible alignment model provides an excellent analytical tool to evaluate and visualize the effect of ligand chemical structure with respect to receptor binding mode and biological activity.
- Qvortrup, Katrine,Jensen, Jakob F.,S?rensen, Mikael S.,Kouskoumvekaki, Irene,Petersen, Rasmus K.,Taboureau, Olivier,Kristiansen, Karsten,Nielsen, Thomas E.
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- Synthesis, Antimicrobial Evaluations, and DNA Photo Cleavage Studies of New Bispyranopyrazoles
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The bispyranopyrazoles (4a, 4b, 4c, 4d, 4e, 4f, 4g) were synthesized from the reactions of dibenzaldehydes (2a, 2b, 2c, 2d, 2e, 2f, 2g) with 3-methylpyrazole-5-one 3 and malononitrile by refluxing under alcoholic medium. The dibenzaldehydes were obtained from the O-alkylation of 3-hydroxybenzaldehyde with suitable 1,ω-dibromoalkanes under the alkaline conditions in the presence of dry EtOH/DMF. The structures of bisheterocyclics were determined from rigorous analysis of their spectral parameters (IR,1H-NMR,13C-NMR, and ESI-MS). The newly prepared compounds were screened for their antimicrobial activity against seven bacterial and five fungal strains. The DNA photo cleavage potential of these compounds was also evaluated by using agarose gel electrophoresis, and bispyranopyrazoles 4b, 4d and 4e exhibited significant level of DNA photocleavage activity.
- Yusuf, Mohamad,Kaur, Manvinder,Sohal, Harvinder Singh
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p. 706 - 713
(2017/02/05)
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- Glycerol assisted eco-friendly strategy for the facile synthesis of 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ols) and 2-aryl-2,3-dihydroquinazolin-4(1H)-ones under catalyst-free conditions
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Abstract: This article describes glycerol mediated eco-friendly approaches for the convenient access of structurally diverse 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) and 2-aryl-2,3-dihydroquinazolin-4(1H)-one motifs under catalyst-free conditions. Prominent advantages include clean processes, atom-efficiency, simplicity of the work-up, neutral conditions, low-cost reaction medium, excellent product yield and solvent reusability, in addition to relatively shorter reaction times. Graphical Abstract: [Figure not available: see fulltext.]
- Ramesh, Rathinam,Nagasundaram, Nagarajan,Meignanasundar, Durairaj,Vadivel, Pullar,Lalitha, Appaswami
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p. 1767 - 1782
(2017/02/15)
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- Aspirin: an efficient catalyst for synthesis of bis (pyrazol-5-ols), dihydropyrano[2,3-c]pyrazoles and spiropyranopyrazoles in an environmentally benign manner
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Abstract: This article aimed to present two facile and environmental friendly routes for the rapid assembly of?biologically active compounds including pyrazol core using aspirin as a novel and green catalyst. The synthesis of bis(pyrazol-5-ol) derivatives was developed via one-pot, pseudo-five-component condensation, and the target dihydropyrano[2,3-c]pyrazoles and spiropyranopyrazoles were prepared by one-pot, four-component reaction. These reactions can be performed in tandem from readily available starting materials. The main merits of the present methods are operational simplicity, no need for column chromatography, inexpensive materials, avoidance of harmless and corrosive acid catalysts, short reaction times, good yields of the products, and utilization of aspirin as a non-toxic, cheap, commercially available, and efficient catalyst.
- Fatahpour, Maryam,Noori Sadeh, Fatemeh,Hazeri, Nourallah,Maghsoodlou, Malek Taher,Lashkari, Mojtaba
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p. 1945 - 1956
(2017/08/14)
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- Piperidine-Promoted Three-Component Condensation: Synthesis of Chromene Heterocycles and Pyrazolotriazoles
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Chromenes, the oxygen-containing heterocyclic compounds, have a “special” place in biologically active natural products and in synthetic chemistry and in the fields of medicinal, agrochemical, cosmetic, and pigment industries. In this work, piperidine was used as a base catalyst for the convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo[g]chromene, and pyrazolo[1,2-a] [1,2,4]triazole derivatives at ambient temperature. This methodology has several advantages including the use of easily accessible and inexpensive catalysts, short reaction times, high yields, convenient work-up, and not needing column chromatography.
- Kangani, Mehrnoush,Hazeri, Nourallah,Yazdani-Elah-Abadi, Afshin,Maghsoodlou, Malek-Taher
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p. 1259 - 1269
(2017/10/18)
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- POLYCYCLIC DERIVATIVES TARGETING RAL GTPASES AND THEIR THERAPEUTICAL APPLICATIONS
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Contemplated compounds, compositions and methods are directed to Ral GTPase inhibitors with improved activity.
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Paragraph 0138-0139
(2017/01/02)
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- Synthesis of some pyrazolone derivatives and evaluation of its antibacterial and cytotoxic activity
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A series of novel pyrazolone derivative were synthesized by two different schemes (scheme-1 by the reaction of phenyl hydrazine and ethyl acetoacetate with substituted benzaldehydes PYR-1 to PYR-4) and (by the reaction of synthesized chalcone with phenyl hydrazine PYR-5) and characterised with its physical parameters (M.P, colour, %yield, solubility etc.). The entire synthesized compound was tested for their antimicrobial activity against Grampositive and Gram-negative strains of bacteria and brimeshrimp bioassay was conducted for evaluation of cytotoxic activity The Investigation of antimicrobial screening data revealed that most of the tested compounds showed moderate to good antimicrobial activity. And cytotoxicity activity of compounds was also found to be satisfactory.
- Parajuli, Rishiram,Banerjee, Janmajoy,Khanal, Hemanta
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p. 2099 - 2106
(2016/02/27)
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- One-pot synthesis of pyrano[2,3-c]pyrazoles using SBA-15-PR-NH2 and their antimicrobial activities
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A simple, green, convenient and efficient method for the synthesis of 6-amino-5-cyanodihydropyrano[2,3-c]pyrazoles 4 is developed through one-pot, three component condensation of 3-methyl-1Hpyrazole-5(4H)-one 1, malononitrile 2, and aromatic aldehydes 3 under mild reaction condition using propylamine functionalized nanoporous silica (SBA-Pr-NH2) as a heterogeneous solid base catalyst. Antimicrobial activity of some synthesized pyrano[2,3-c]pyrazoles against Bacillus subtilis, Staphylococcus aureus and Escherichia coli were measured using disc diffusion method.
- Mohammadi Ziarani, Ghodsi,Nouri, Fatemeh,Rahimifard, Mahshid,Badiei, Alireza,Abolhassani Soorki, Ali
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p. 331 - 337
(2015/09/07)
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- Novel grinding synthesis of pyranopyrazole analogues and their evaluation as antimicrobial agents
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The paper describes the results of a new four-component synthesis of pyranopyrazole heterocycles by solvent-free one-pot grinding of malononitrile, hydrazine, ethyl acetoacetate, and various aldehydes in the presence of a base. The reaction proceeded smoothly at room temperature with good yields in very short reaction time. The synthesised compounds were evaluated for their in vitro antibacterial activity against three different bacterial and three different fungal strains. The highlight of this work is that the synthesis was activity-driven. The brief SAR correlation found that the tested compounds showed better activity against fungal strains.
- Sharma, Ashok,Pallavi, Badvel,Singh, Rajnish Prakash,Jha, Prabhat Nath,Shukla, Paritosh
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p. 1615 - 1627
(2015/09/28)
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- Nano α-Al2O3 supported ammonium dihydrogen phosphate (NH4H2PO4/Al2O3): Preparation, characterization and its application as a novel and heterogeneous catalyst for the one-pot synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3-c]pyrazole derivatives
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A simple, efficient, and environmentally benign route was developed for the preparation of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5,6,7,8-tetrahydrobenzo[b]pyrans and 6-amino-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles from the condensation of various aldehydes, malononitrile, and 1,3-dicarbonyl compounds (1,3-cyclohexanedione or 5,5-dimethyl-1,3-cyclohexanedione) or 3-methyl-1-phenyl-2-pyrazoline-5-one, using NH4H2PO4/Al2O3 with good yields. The use of easily available catalyst, shorter reaction times, better yields, the simplicity of the reaction, the heterogeneous system, and the easy work up are the advantages of the present method. Characterization of the catalyst was performed by FT-IR spectroscopy, X-ray diffraction (XRD) techniques, thermal analysis (TG/DTG) and Transmission electron microscopy (TEM).
- Maleki, Behrooz,Ashrafi, Samaneh Sedigh
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p. 42873 - 42891
(2015/02/19)
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- Synthesis of some bisindolyl analogs for in vitro cytotoxic and DNA cleavage studies
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One-pot, three components, conventional and microwave-assisted synthesis of bisindolyl analogs is described. Michael addition of preformed 2,5-disubstituted indole-3-carboxaldehydes and 3-methyl-1H-pyrazol-5(4H)-one with 2,5-disubstituted indoles under solvent and catalyst-free conditions afforded the hitherto unreported 2,5-disubstituted bisindolyl analogs bearing a pyrazolone moiety in excellent yields. All the synthesized compounds were characterized using IR, 1H NMR, mass spectral, and analytical data. The analogs were screened for in vitro cytotoxic and DNA cleavage studies. Among the screened compounds 4c, 4f, and 4h-4j have emerged as most potent cytotoxic and 4c and 4f-4h as active DNA cleavage analogs.
- Sasidhar,Biradar
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p. 3518 - 3526
(2013/07/11)
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- Synthesis of pyranopyrazoles using isonicotinic acid as a dual and biological organocatalyst
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In this study, a green, simple and efficient method for the preparation of 6-amino-4-(4-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c] pyrazoles by means of a one-pot four component condensation reaction of aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate is reported. The reaction utilizes isonicotinic acid as a dual and biological organocatalyst at 85 °C under solvent-free conditions.
- Zolfigol, Mohammad Ali,Tavasoli, Mahsa,Moosavi-Zare, Ahmad Reza,Moosavi, Parvin,Kruger, Hendrik Gerhardus,Shiri, Morteza,Khakyzadeh, Vahid
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p. 25681 - 25685
(2013/12/04)
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- Synthesis and antimicrobial evaluation of novel pyrazolones and pyrazolone nucleosides
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The synthesis of a novel series of 4-Arylhydrazono-5-methyl-1,2- dihydropyrazol-3-ones 4a-h, and their N 2-Alkyl and acyclo, glucopyranosyl, and ribofuranosyl derivatives is described. K2CO 3 catalyzed alkylation of 4a-h with allyl bromide, propargyl bromide, 4-bromobutyl acetate, 2-Acetoxyethoxymethyl bromide, and 2,3,4,6-tetra-O- Acetyl-D-glucopyranosyl bromide proceeded selectively at the N 2-position of the pyrazolinone ring. Glycosylation of 4a with 1,2,3,5-tetra-O-Acetyl-D-ribofuranose under Vorbruggen glycosylation conditions gave the corresponding N 2-4-Arylhydrazonopyrazolone ribofuranoside 9a in good yield. Conventional deprotection of the acetyl protected nucleosides furnished the corresponding 4-Arylhydrazonopyrazolone nucleosides in good yields. Selected numbers of the newly synthesized compounds were screened for antimicrobial activity. Compounds 4b, 12a, and 14d showed moderate activities against Aspergillus flavus, Penicillium sp., and Escherichia coli.
- Hassan, Abdalla E. A.,Moustafa, Ahmed H.,Tolbah, Mervat M.,Zohdy, Hussein F.,Haikal, Abdelfattah Z.
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p. 783 - 800
(2013/01/16)
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- Synthesis, biological evaluation of some arylsulfonyl, carboxamide derivatives of 3-methyl-1H-pyrazol-5(4H)-one
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Synthesis of pyrazolone , its derivatives is of particular interest in heterocyclic chemistry due to their pharmaceutical importance. In the present study arylsulfonyl (1a-f , 2a-f) , carboxamide (3a-e) derivatives of 3-methyl-1H-pyrazol-5(4H)-one were synthesized. The reaction of pyrazolone with arylsulfonyl chlorides resulted in mono (1a-f) , disubstituted (2a-f) arylsulfonyl derivatives of 3-methyl-1H-pyrazol-5(4H)-one. On the other h, the pyrazolone on treatment with different isocyanates yielded respective carboxamides (3a-e). The synthesized compounds were screened for urease inhibition, antibacterial, antioxidant assays, exhibit promising urease inhibition. Compound 1e was observed to be most active urease inhibitor in the series with 91.9 % inhibition. However, the antioxidant, antibacterial activities of all the compounds were non-significant at non-toxic concentration.
- Sardar, Sabahat,Akhtar, Tashfeen,Hameed, Shahid,Khan, Khalid Mohammed
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p. 1531 - 1538
(2013/05/08)
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- Simple and efficient protocol for the synthesis of novel dihydro-1H-pyrano[2,3-c]pyrazol-6-ones via a one-pot four-component reaction
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Ba(OH)2 catalyzed simple and efficient one-pot four-component reaction of Meldrums acid, ethyl acetoacetate, hydrazine hydrate, and aromatic aldehydes to give 3-methyl-4-aryl-4,5-dihydro-1H-pyrano[2,3-c]pyrazol-6-ones in refluxing water is reported. The yields are high and the reactions go to completion in 1-2 h.
- Azzam, Sadeq Hamood Saleh,Pasha
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p. 6834 - 6837
(2013/01/15)
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- Solvent-free, microwave assisted Knoevenagel condensation of novel 2,5-disubstituted indole analogues and their biological evaluation
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A rapid, efficient and environmental benign methodology for the preparation of 2,5-disubstituted indole analogues is developed. 2,5-Disubstituted indole-3-carboxaldehydes (1a-c) undergo Knoevenagel condensation with barbiturates (2 & 4), thiazolidine-2,4-dione (6) and 3-methyl-1H-pyrazol- 5(4H)-one (8) in solvent-free, NH4OAc catalyzed, microwave assisted reaction. Structures of the products thus obtained were confirmed by their m.p, Elemental analysis, IR, 1H NMR, 13C NMR and Mass spectral data. The in vitro antioxidant and cytotoxic activities against three tumor cell lines were evaluated and discussed in terms of their structural differences. Among the screened compounds 9b, 9c, 7b and 5b exhibited excellent antioxidant activity. Compounds 9b, 9c and 7b have shown strong cytotoxicity among the compounds tested.
- Biradar,Sasidhar
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experimental part
p. 6112 - 6118
(2012/01/03)
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- 2-Substituted-8-methyl-3,6-dihydroimidazo[4,5-c]pyrazolo[3,4-e] pyridazine as an anti-inflammatory agent
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A series of 8-methyl-2-substituted-3,6-dihydroimidazo[ 4,5-c]pyrazolo[3,4- e]pyridazine compounds have been synthesized in the present investigation utilizing Philips condensation (Philips, J Chem Soc 2393-2399, 1928). The anti-inflammatory activity of the synthesized compounds was evaluated using a carrageenin rat model. Springer Science+Business Media, LLC 2010.
- Tewari, Ashish Kumar,Dubey, Rashmi,Mishra, Anil
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scheme or table
p. 125 - 129
(2012/03/10)
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- γ-Alumina as a recyclable catalyst for the four-component synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5- carbonitriles in aqueous medium
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γ-Alumina as an expedient and recyclable catalyst for the synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5- carbonitriles in water via a four-component reaction is established. Comparative study of the efficacy of γ-alumina, basic alumina and KF-alumina is also discussed. The method presented is mild, environment friendly, inexpensive and functionality tolerable to give the products in good to excellent yields.
- Mecadon, Hormi,Rohman, Md. Rumum,Rajbangshi, Mantu,Myrboh, Bekington
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experimental part
p. 2523 - 2525
(2011/05/09)
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