Search results for: Dipak K. Raval

Items from 1 to 20 out of 21 results

article

C−H Functionalization Reactions of 1‐Aryl‐5‐pyrazolones

Vishal B. Purohit, Ronak V. Prajapati, Vaibhav D. Prajapati, Sharad C. Karad, more

European Journal of Organic Chemistry > 2022 > 45 > n/a - n/a

In this contribution, we provide a comprehensive overview on the C−H activation/functionalization reactions of 1‐aryl‐5‐pyrazolones, in particular, 1‐aryl‐3‐methyl‐1H‐pyrazol‐5(4H)‐ones (edaravones) and their N‐methyl analogues i. e., antipyrines covering the literature since 2013 (the year of the first report). This review summarizes the recent progress in C−H functionalization reactions of 1‐aryl‐5‐pyrazolones...

article

Sonochemical synthesis of 2,3-dihydro-4(1H)-quinazolinones and 1-amidoalkyl-2-naphthols using magnetic nanoparticle-supported ionic liquid as a heterogeneous catalyst

Harsh N. Dadhania, Dipak K. Raval, Abhishek N. Dadhania

Research on Chemical Intermediates > 2018 > 44 > 1 > 117-134

Ultrasound-promoted synthesis of 2,3-dihydro-4(1H)-quinazolinones and 1-amidoalkyl-2-naphthols were carried out using magnetic nanoparticle-immobilized ionic liquid (IL@MNP) as a magnetically separable catalyst. Ultrasound accelerates the reaction at ambient temperature making the protocol clean, simple and greener compared to conventional procedures. The catalyst showed high activity and stability...

article

A green protocol for the synthesis of quinoxaline derivatives catalyzed by polymer supported sulphanilic acid

Umesh P. Tarpada, Bhautik B. Thummar, Dipak K. Raval

Arabian Journal of Chemistry > 2017 > 10 > S2 > S2902-S2907

Polymer supported sulphanilic acid was found to be an effective heterogeneous catalyst for one pot synthesis of various quinoxaline derivatives from the condensation reaction between 1,2-diamines and 1,2-dicarbonyl compounds in ethanol. Synthesis was attempted under reflux as well as at room temperature using ethanol as the solvent to afford excellent yields. Heterogeneity of the catalyst allowed...

article

Synthesis and biological screening of novel 2-morpholinoquinoline nucleus clubbed with 1,2,4-oxadiazole motifs

Sharad C. Karad, Vishal B. Purohit, Rahul P. Thummar, Beena K. Vaghasiya, more

European Journal of Medicinal Chemistry > 2017 > 126 > C > 894-909

Novel series of 2-morpholinoquinoline scaffolds (6a-n), containing the 1,2,4-oxadiazole and moiety, was designed and synthesized in good yield (76–86%). The synthesized compounds were screened for their preliminary in vitro antimicrobial activity against a panel of pathogenic strains of bacteria and fungi. Molecular docking and pharmacokinetic study were carried out for the prepared compounds. The...

article

Ionic liquid promoted facile and green synthesis of 1,8-dioxo-octahydroxanthene derivatives under microwave irradiation

Abhishek N. Dadhania, Vaibhav K. Patel, Dipak K. Raval

Journal of Saudi Chemical Society > 2017 > 21 > S1 > S163-S169

An efficient and environmentally benign procedure for the synthesis of 1,8-dioxo-octahydroxanthene by condensation reaction between 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and structurally diverse aldehydes using carboxy functionalized ionic liquid under microwave irradiation is described. The methodology provides synergy of ionic liquid and microwave irradiation which offers several advantages...

article

Highly enantioselective sulpha-Michael addition to α,β-unsaturated carbonyl scaffolds catalysed by allyloxy-N-(1-benzyl) cinchonidinium bromide in water at room temperature

Piyush N. Kalaria, Jemin R. Avalani, Dipak K. Raval

Tetrahedron: Asymmetry > 2016 > 27 > 19 > 947-953

Allyloxy-N-(1-benzyl) cinchonidinium bromide was found to be an effective organocatalyst for asymmetric Michael reactions of thiols with various α,β-unsaturated ketones, acids and esters to provide optically active sulphides with high enantiomeric excess (91–100% ee) and chemical yields (up to >98%). The reaction was performed with 2–8mol% of catalyst in water at room temperature using tetra-n-butyl...

article

Polymer supported sulphanilic acid – A novel green heterogeneous catalyst for synthesis of benzimidazole derivatives

Umesh P. Tarpada, Bhautik B. Thummar, Dipak K. Raval

Journal of Saudi Chemical Society > 2016 > 20 > 5 > 530-535

Polymer supported sulphanilic acid was synthesized and used as green, reusable and heterogeneous catalyst and duly characterized using chemical methods like determination of free hydroxyl content, epoxy equivalent weight and free sulphonic acid content as well as infrared spectroscopy and thermogravimetric analysis. The prepared catalyst was applied for one-pot synthesis of 2-substituted benzimidazoles...

article

One-pot solvent-free rapid and green synthesis of 3,4-dihydropyrano[c]chromenes using grindstone chemistry

Devji S. Patel, Jemin R. Avalani, Dipak K. Raval

Journal of Saudi Chemical Society > 2016 > 20 > S1 > S401-S405

An easy solvent-free method is described for the synthesis of 3,4-dihydropyrano[c]chromenes by a one pot three component coupling reaction of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin using basic ionic liquid as the catalyst by grindstone chemistry. The salient features of this one pot protocol are short reaction times, cleaner reaction profiles and simple workup.

article

Novel morpholinoquinoline nucleus clubbed with pyrazoline scaffolds: Synthesis, antibacterial, antitubercular and antimalarial activities

Sharad C. Karad, Vishal B. Purohit, Parth Thakor, Vasudev R. Thakkar, more

European Journal of Medicinal Chemistry > 2016 > 112 > C > 270-279

A series of novel morpholinoquinoline based conjugates with pyrazoline moiety were synthesized under microwave irradiation. The newly synthesized compounds were screened for their preliminary in vitro antibacterial activity against a panel of pathogenic strains of bacteria and fungi, antituberculosis activity against Mycobacterium tuberculosis H₃₇Rv and antimalarial activity against Plasmodium falciparum...

article

Palladium N-heterocyclic carbene catalyzed regioselective thiolation of 1-aryl-3-methyl-1H-pyrazol-5(4H)-ones using aryl thiols

Vishal B. Purohit, Sharad C. Karad, Kirit H. Patel, Dipak K. Raval

Tetrahedron > 2016 > 72 > 8 > 1114-1119

A palladium N-heterocyclic carbene [Pd(NHC)Cl₂] complex of Vitamin B₁ developed earlier in our lab was also found to be an effective catalyst for regioselective thiolation via C–H bond activation of 1-aryl-3-methyl-1H-pyrazol-5(4H)-ones 1a–c using aryl thiols 2a–e. The protocol was found to be simple, efficient and highly regioselective to afford the target products 3a–o in good to excellent yields.

article

Design, synthesis and characterization of fluoro substituted novel pyrazolylpyrazolines scaffold and their pharmacological screening

Sharad C. Karad, Vishal B. Purohit, Dipak K. Raval

European Journal of Medicinal Chemistry > 2014 > 84 > Complete > 51-58

A novel series of fluoro substituted pyrazolylpyrazolines 7a–l was synthesized in good to excellent yield (77–88%) from pyrazole chalcones 5a–d and substituted phenyl hydrazine hydrochlorides 6a–c under microwave irradiation. The newly synthesized compounds were screened for their preliminary in vitro antibacterial activity against a panel of pathogenic stains of bacteria and fungi, antituberculosis...

article

An efficient approach for the synthesis of spirooxindole derivatives catalyzed by novel sulfated choline based heteropolyanion at room temperature

Shailesh P. Satasia, Piyush N. Kalaria, Jemin R. Avalani, Dipak K. Raval

Tetrahedron > 2014 > 70 > 35 > 5763-5767

A new zwitterionic salt, sulfated choline based heteropolyanion, which was reported earlier by our group, has been found to be very effective for the synthesis of spirooxindole derivatives at room temperature. The heteropolyanion based on sulfated ionic liquid (HIL) showed promising features for the reaction, such as shorter reaction time, high product yields (about 90–95%), simple work up, easy removal,...

article

Heteropolyanion-based sulfated ionic liquid catalyzed formamides synthesis by grindstone chemistry

Shailesh P. Satasia, Piyush N. Kalaria, Dipak K. Raval

Journal of Molecular Catalysis. A, Chemical > 2014 > 391 > Complete > 41-47

A novel heteropolyanion-based sulfated ionic liquid (HIL-[Ch-OSO ₃ H] ₃ W ₁₂ PO ₄₀ ) was prepared by pairing sulfate functionalized cholinium cation [N,N,N-trimethyl-2-(sulfooxy)ethanaminium] with catalytically active phosphotungstic acid anion (W ₁₂ PO ₄₀ ³⁻ ). It was characterized by ¹ H NMR, FT-IR, EDX, XRD, TGA and elemental analysis...

article

Ultrasound-assisted one-pot four-component synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole scaffold and their biological broadcast

Piyush N. Kalaria, Shailesh P. Satasia, Jemin R. Avalani, Dipak K. Raval

European Journal of Medicinal Chemistry > 2014 > 83 > Complete > 655-664

An alternative and environmentally caring way for the synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole nucleus is reported by one-pot four-component cyclocondensation reaction of substituted 5-(1H-imidazol/4-methyl-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (3a–b), malononitrile (4), ammonium acetate (5) and aromatic (6a–f)/heterocyclic methyl ketones (7a–d)...

article

Synthesis, characterization and pharmacological screening of some novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives

Piyush N. Kalaria, Shailesh P. Satasia, Dipak K. Raval

European Journal of Medicinal Chemistry > 2014 > 78 > C > 207-216

A new category of polyhydroquinoline derivatives 8a–t were synthesized in moderate to good yield (64–85%) by one-pot three-component cyclocondensation reaction of 5-(1H-imidazol-1-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 3 with various enaminones 6a–h and different active methylene compounds (malononitrile 7a, ethylcaynoacetate 7b and caynoacetamide 7c) in absolute ethanol. The newly synthesized...

article

Saccharomyces cerevisiae catalyzed one pot synthesis of isoindolo[2,1-a]quinazoline performed under ultrasonication

Jemin R. Avalani, Devji S. Patel, Dipak K. Raval

Journal of Molecular Catalysis. B, Enzymatic > 2013 > 90 > Complete > 70-75

An efficient and simple one pot method has been developed for the synthesis of isoindolo[2,1-a]quinazolines using Saccharomyces cerevisiae (baker's yeast) as a whole cell biocatalyst at room temperature. The synergetic effect of baker's yeast and ultrasound irradiation has been discussed.

article

Polymer supported sulphanilic acid: A highly efficient and recyclable green heterogeneous catalyst for the construction of 4,5-dihydropyrano[3,2-c]chromenes under solvent-free conditions

Jashmin P Patel, Jemin R Avalani, Dipak K Raval

Journal of Chemical Sciences > 2013 > 125 > 3 > 531-536

Polystyrene divinylbenzene supported sulphanilic acid was prepared, characterized and tested as an acidic catalyst in multicomponent organic synthesis. This is the first report focusing on the development of one-pot solvent-free synthesis of 4,5- dihydropyrano [3,2-c]chromenes under acidic conditions. It proved to be a versatile catalyst for microwave-assisted synthesis of 4,5-dihydropyrano[3,2-c]chromenes...

article

Catalyst-free sonochemical synthesis of 1,8-dioxo-octahydroxanthene derivatives in carboxy functionalized ionic liquid

Abhishek N. Dadhania, Vaibhav K. Patel, Dipak K. Raval

Comptes rendus - Chimie > 2012 > 15 > 5 > 378-383

An efficient methodology for the synthesis of 1,8-dioxo-octahydroxanthene derivatives under ultrasonic irradiation at room temperature using carboxy functionalized ionic liquid 1-carboxymethyl-3-methylimidazolium tetrafluoroborate, [cmmim][BF ₄ ], without any added catalyst, is described. The reaction involves condensation between 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and structurally...

article

1-Methylimidazolium trifluoroacetate [Hmim]Tfa: Mild and efficient Brønsted acidic ionic liquid for Hantzsch reaction under microwave irradiation

Jemin R Avalani, Devji S Patel, Dipak K Raval

Journal of Chemical Sciences > 2012 > 124 > 5 > 1091-1096

One pot synthesis of 1,4-dihydropyridine derivatives was achieved via condensation of various β-ketoesters with aromatic/aliphatic aldehydes and ammonium acetate. The reaction was catalysed by a stable and reusable Brønsted acidic ionic liquid (IL), 1-methyl-imidazolium trifluoroacetate ([Hmim]Tfa), under microwave (MW) irradiation. The synergistic combination of MW with IL can potentially go a long...

article

A facile approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones using a microwave promoted Biginelli protocol in ionic liquid

Abhishek N Dadhania, Vaibhav K Patel, Dipak K Raval

Journal of Chemical Sciences > 2012 > 124 > 4 > 921-926

Carboxy functionalized ionic liquid [cmmim][BF₄] has been demonstrated to be an efficient and green catalyst for the one pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones heterocycles under microwave irradiation. The ionic liquid-microwave strategy represents an easy access to Biginelli compounds with high yields and purity. The protocol was found to be compatible with different structurally diverse...

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Search results for: Dipak K. Raval

C−H Functionalization Reactions of 1‐Aryl‐5‐pyrazolones

Sonochemical synthesis of 2,3-dihydro-4(1H)-quinazolinones and 1-amidoalkyl-2-naphthols using magnetic nanoparticle-supported ionic liquid as a heterogeneous catalyst

A green protocol for the synthesis of quinoxaline derivatives catalyzed by polymer supported sulphanilic acid

Synthesis and biological screening of novel 2-morpholinoquinoline nucleus clubbed with 1,2,4-oxadiazole motifs

Ionic liquid promoted facile and green synthesis of 1,8-dioxo-octahydroxanthene derivatives under microwave irradiation

Highly enantioselective sulpha-Michael addition to α,β-unsaturated carbonyl scaffolds catalysed by allyloxy-N-(1-benzyl) cinchonidinium bromide in water at room temperature

Polymer supported sulphanilic acid – A novel green heterogeneous catalyst for synthesis of benzimidazole derivatives

One-pot solvent-free rapid and green synthesis of 3,4-dihydropyrano[c]chromenes using grindstone chemistry

Novel morpholinoquinoline nucleus clubbed with pyrazoline scaffolds: Synthesis, antibacterial, antitubercular and antimalarial activities

Palladium N-heterocyclic carbene catalyzed regioselective thiolation of 1-aryl-3-methyl-1H-pyrazol-5(4H)-ones using aryl thiols

Design, synthesis and characterization of fluoro substituted novel pyrazolylpyrazolines scaffold and their pharmacological screening

An efficient approach for the synthesis of spirooxindole derivatives catalyzed by novel sulfated choline based heteropolyanion at room temperature

Heteropolyanion-based sulfated ionic liquid catalyzed formamides synthesis by grindstone chemistry

Ultrasound-assisted one-pot four-component synthesis of novel 2-amino-3-cyanopyridine derivatives bearing 5-imidazopyrazole scaffold and their biological broadcast

Synthesis, characterization and pharmacological screening of some novel 5-imidazopyrazole incorporated polyhydroquinoline derivatives

Saccharomyces cerevisiae catalyzed one pot synthesis of isoindolo[2,1-a]quinazoline performed under ultrasonication

Polymer supported sulphanilic acid: A highly efficient and recyclable green heterogeneous catalyst for the construction of 4,5-dihydropyrano[3,2-c]chromenes under solvent-free conditions

Catalyst-free sonochemical synthesis of 1,8-dioxo-octahydroxanthene derivatives in carboxy functionalized ionic liquid

1-Methylimidazolium trifluoroacetate [Hmim]Tfa: Mild and efficient Brønsted acidic ionic liquid for Hantzsch reaction under microwave irradiation

A facile approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones using a microwave promoted Biginelli protocol in ionic liquid

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