Dattatraya R. Chandam

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

Sulfamic acid-catalyzed multicomponent synthesis of 7-phenyl-7,12 dihydrobenzo(h)pyrido[2,3-b]naphthydrin-6(5H)-one derivatives: a green avenue

A series of novel 7-phenyl-7,12-dihydrobenzo(h)pyrido[2,3-b]naphthydrin-6(5H)-one were synthesized by a one-pot three-component condensation of 2,4-dihydroxyquinoline, 2-amino pyridine and various aromatic aldehydes with sulfamic acid as an enviro-economic catalyst. The salient features of this method consist of high atom economy and yields, short reaction time, non-carcinogenic solvents, and chromatography-free work-up procedure. Fascinatingly, the catalyst can be reused for up to four cycles giving good to excellent yields. By employing this method, a series of 14 pyrido[2,3-b]naphthydrin compounds were synthesized. This procedure is projected as a green avenue in the combinatorial synthesis of biologically active naphthydrin derivatives.Graphical Abstract

Low transition temperature mixtures prompted one-pot synthesis of 5, 10 dihydropyrimido[4,5-b]quinoline-2,4(1 H ,3 H )-dione derivatives

An efficient green protocol has been investigated for the synthesis of pyrimido[4,5-b]quinolines derivatives via one-pot three-component condensation of 4-chloro aniline, aromatic aldehyde and barbituric acid using low transition temperature mixtures as new generation and sustainable solvents. The process was accomplished with the use of greener and recyclable reaction media, simple methodology, easy workup procedures and no chromatographic purification with high yield. This new approach is expected to discover some significance in combinatorial synthesis of biologically active scaffolds.Graphical Abstract

9-(3,4-Dimeth-oxy-phen-yl)-3,3,6,6-tetra-methyl-1,2,3,4,5,6,7,8,9,10-deca-hydro-acridine-1,8-dione.

The asymmetric unit of the title compound, C25H31NO4, contains two independent molecules. In one molecule, the benzene ring and an attached methoxy group were refined as disordered over two sets of sites in a 0.65 (4): 0.35 (4) ratio. In both molecules, the central ring of the acridinedione system adopts a flattened boat conformation. The four essentially planar atoms of this ring [maximum deviations = 0.006 (5) Å in both molecules] forms dihedral angles of 86.8 (2) and 87.6 (2)°, respectively, with the major and minor components in the disordered benzene ring and 87.3 (2)° with the benzene ring in the fully ordered molecule. The two outer rings of the acridinedione system adopt sofa conformations in both molecules. In the crystal, N—H⋯O hydrogen bonds form two independent chains along [100]. C—H⋯O hydrogen bonds link the chains, forming a three-dimensional network.

2-Amino-7,7-dimethyl-5-oxo-4-[3-(trifluoro-meth-yl)phen-yl]-5,6,7,8-tetra-hydro-4H-chromene-3-carbonitrile.

In the title molecule, C19H17F3N2O2, the fused cyclohexene and pyran rings adopt sofa and flattened boat conformations, respectively. The four essentially planar atoms of the pyran ring [maximum deviation = 0.008 (2) Å] form a dihedral angle of 88.13 (9)° with the benzene ring. The F atoms of the trifluoromethyl group were refined as disordered over three sets of sites in a 0.507 (7):0.330 (7):0.163 (3) ratio. In the crystal, molecules are connected into inversion dimers via pairs of N—H⋯N hydrogen bonds and these dimers are further linked by N—H⋯O hydrogen bonds into a two-dimensional network parallel to (100).

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