Abhijeet Mulik

Novel Brønsted Acidic Ionic Liquid ([CMIM][CF3COO]) Prompted Multicomponent Hantzsch Reaction for the Eco-Friendly Synthesis of Acridinediones: An Efficient and Recyclable Catalyst

AbstractsA novel, highly efficient and recyclable Brønsted acidic ionic liquid ([CMIM][CF3COO]) has been successfully implemented for the synthesis of acridinediones in aqueous media. Recyclability of novel catalyst, high yields, use of environmentally benign aqueous media as solvent, simple product isolation, high atom economy and sidestep to column chromatography are the noteworthy features of this protocol. This protocol is competent for producing wide library of acridinediones in good to excellent yields. Furthermore, molecular structure and relative stereochemistry of 4c and 4s derivatives were confirmed by single-crystal X-ray diffraction.Graphical Abstract

(±)-Camphor-10-sulfonic acid catalyzed atom efficient and green synthesis of triazolo[1,2-a]indazole-triones and spiro triazolo[1,2-a]indazole-tetraones

Abstract(±)-Camphor-10-sulfonic acid is used for the synthesis of triazolo[1,2-a]indazole-triones and spiro triazolo[1,2-a]indazole-tetraones by condensation reaction of dimedone, urazole and aromatic aldehydes or isatin. The noteworthy aspects of this new method are high yields, high atom efficiency, use of non-toxic solvent, mild conditions, simple workup and synthesis of complex molecules using an eco-friendly, inexpensive catalyst.Graphical Abstract

Oxalic acid dihydrate: proline as a new recyclable designer solvent: a sustainable, green avenue for the synthesis of spirooxindole

The quest to develop an environmentally friendly, sustainable protocol for immensely bioactive spirooxindole derivatives has encouraged to explore oxalic acid dihydrate: proline low transition temperature mixture as a new designer solvent for the said synthesis at room temperature. It has been successfully applied for the three component reaction of isatin, malononitrile or ethyl cyanoacetate and 1,3–dicarbonyl compounds for the first time. Moderate to good yield of the products, shorter reaction time, energy efficiency, chromatography-free purification process, recyclability and high atom economy are the captivating feature of this protocol which will find applications in multi-component, diversity-oriented synthesis.Graphical Abstract

Protic ionic liquids: a lucid, rational tool for synthesis of phthalazinediones, quinoxalines and benzopyrans

Protic ionic liquids (PILs), which are easily produced through the combination of a Brønsted acid and Brønsted base, such as [Mim]Ac and 1,4-diazabicyclo[2.2.2]octane (DABCO):AcOH:H2O (1:1:3), were found to be lucid, tunable tool for synthesis of various heterocyclic motifs such as phthalazinediones, quinoxalines and benzopyrans. These PILs were found to be efficient for synthesis of diverse heterocyclic derivatives, along with demonstrating noteworthy aspects such as high yields, isolation of pure products without column chromatography and recyclable reaction media.Graphical abstract

Synthesis of some novel quinone diimine derivatives of benzo-15-crown-5 for application in Hg 2+ recognition

A series of novel fluoroionophore bearing derivatives of benzo-15-crown-5 were synthesized by the amination of benzo-15-crown-5 followed by condensation with different quinones in the presence of titanium tetrachloride (TiCl4 ) and 1,4-diazabicyclo-[2.2.2]octane. The compounds were characterized by infrared, (1) H and (13) C nuclear magnetic resonance, mass spectroscopy and elemental analysis. Absorption and fluorescence spectral characteristics of these compounds were studied. It was observed that the anthraquinone derivative was acting as an Hg(2+) ion sensor.

Novel crown ether functionalized imidazolium-based acidic ionic liquid catalyzed synthesis of pyrazole derivatives under solvent-free conditions

An innovatively designed novel crown ether functionalized imidazolium-based reusable acidic ionic liquid [crown ether MIm] [HSO4] has been efficiently implemented for the synthesis of pyrazole derivatives using various substituted enaminones, hydrazine hydrate and phenyl hydrazine under solvent-free conditions. Structural novelty and task efficiency of the catalyst, high yields of desired products, greener approach attributing high atom economy and solvent-free conditions render this protocol suitable to cope with the current demand in contemporary organic chemistry. The inventive idea of utilizing crown ether functionalized ionic liquid as a catalyst was for the first time demonstrated in this protocol.Graphical Abstract

Efficient, rapid avenue for synthesis of highly substituted piperidines using polystyrene sulfonic acid

A proficient and meticulously designed diasterioselective, multicomponent, one-pot synthesis of densely substituted piperidine derivatives has been elaborated using polystyrene sulfonic acid catalyst via tandem reactions of 1,3-dicarbonyl compounds, aromatic aldehydes and various amines. Shorter reaction times, high yields and a polymer-supported inexpensive catalyst are the noteworthy aspects of the scaffold.Graphical Abstract

Novel dibenzo-18-crown-6 ether functionalized bis-benzimidazole derivatives: synthesis and antifungal evaluation

A series of novel 18-crown-6 ether functionalized bis-benzimidazole derivatives (3a–g) have been synthesized by reacting various substituted ortho-phenylene diamines and pyridine diamines with 4,4′-diformyl dibenzo-18-crown-6 ether (1). The required starting material 4,4′-diformyl dibenzo-18-crown-6 ether (1) was prepared by Duff formylation method. All synthesized novel molecules have been identified on the basis of infrared (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass spectroscopy (MS), and elemental analyses. The title compounds (3a–g) were tested for antifungal activity against Aspergillus niger, Trichothecium sp., Rhizopus sp., and Sclerotium rolfsii fungi species using agar well diffusion method, showing mild to good results.Graphical abstract

Synthesis and Cation Recognition Study of Novel Benzo Crown Ether Functionalized Enamine Derivatives

Abstract A novel series of benzo crown ether (dibenzo 18-crown-6 ether, benzo 18-crown-6 ether, and benzo 15-crown-5 ether) functionalized enamines derivatives from amino benzo crown ether (4-amino dibenzo 18-crown-6 ether, 4-amino benzo 18-crown-6 ether, 4-amino benzo 15-crown-5 ether) and substituted 3-(dimethylamino)-1-phenylprop-2-en-1-one compounds have been synthesized. All the synthesized compounds were characterized by infrared, 1H NMR, 13C NMR, distortionless enhancement polarization transfer, and mass and elemental analysis techniques. The cation recognition property for benzo crown ether enamine 8a was studied by absorption and fluorescence spectroscopy. GRAPHICAL ABSTRACT

2-Amino-7,7-dimethyl-5-oxo-4-[3-(trifluoro­meth­yl)phen­yl]-1,4,5,6,7,8-hexa­hydro­quinoline-3-carbonitrile

In the title molecule, C19H18F3N3O, the dihydropyridine and cyclohexene rings both adopt sofa conformations. The five essentially planar atoms of the dihydropyridine ring [maximum deviation = 0.039 (2) Å] form a dihedral angle of 88.19 (8)° with the benzene ring. The F atoms of the trifluoromethyl group were refined as disordered over two sets of sites in a 0.840 (3):0.160 (3) ratio. In the crystal, N—H⋯O and N—H⋯N hydrogen bonds link molecules into a two-dimensional network parallel to (100).