Vijith Kumar

New 4-(2-(4-alkoxyphenyl)-6-methoxypyridin-4-yl)benzonitriles: synthesis, liquid crystalline behavior and photo physical properties

A new series of luminescent 4-(2-(4-alkoxyphenyl)-6-methoxypyridin-4-yl)benzonitriles containing three ring systems, viz. methoxy pyridine, benzonitrile and alkoxy benzene with variable alkoxy chain length, with bent-core structures were synthesized as potential mesogens and characterized by spectral techniques. Their liquid crystalline behavior was investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and variable temperature powder X-ray diffraction (PXRD) measurements. The study reveals that compounds with shorter chain lengths [i.e. m = 4] exclusively exhibit the nematic phase while compounds with longer chain lengths [i.e. m = 6–14 (only even)] show predominantly the orthorhombic columnar phase. Single crystal X-ray analysis of 4-(2-(4-butyloxy/octyloxyphenyl)-6-methoxypyridin-4-yl)benzonitriles reveals that they possess slightly non-planar unsymmetrical bent structures and their molecular packing consists of nonconventional H-bond interactions; it also explains the observed liquid crystalline phase. An optical study indicates that the title compounds are good blue emitting materials showing absorption and emission bands in the range 335–345 nm and 415–460 nm, respectively. An electrochemical study of 4-(2-(4-octyloxyphenyl)-6-methoxypyridin-4-yl)benzonitrile shows a band gap of 1.89 eV with HOMO and LUMO energy levels of −5.06 and −3.17 eV, respectively. Also, density functional theory (DFT) calculations confirm its optimized geometry, electronic absorption and frontier molecular orbital distributions.

Identification and characterization of novel indole based small molecules as anticancer agents through SIRT1 inhibition

In our pursuit to develop new potential anticancer leads, we designed a combination of structural units of indole and substituted triazole; and a library of 1-{1-methyl-2-[4-phenyl-5-(propan-2-ylsulfanyl)-4H-1,2,4-triazol-3-yl]-1H-indol-3-yl}methanamine derivatives was synthesized and characterized. Cytotoxic evaluations of these molecules over a panel of three human cancer cell lines were carried out. Few molecules exhibited potent growth inhibitory action against the treated cancer cell lines at lower micro molar concentration. An in vitro assay investigation of these active compounds using recombinant human SIRT1 enzyme showed that one of the compounds (IT-14) inhibited the deacetylation activity of the enzyme. The in vivo study of IT-14 exemplified its promising action by reducing the prostate weight to the body weight ratio in prostate hyperplasia animal models. A remarkable decrease in the disruption of histoarchitecture of the prostate tissues isolated from IT-14 treated animal compared to that of the positive control was observed. The molecular interactions with SIRT1 enzyme were also supported by molecular docking simulations. Hence this compound can act as a lead molecule to treat prostatic hyperplasia.

Characterisation and bioactivity of oosporein produced by endophytic fungus Cochliobolus kusanoi isolated from Nerium oleander L.

Bioactive compounds comprising secondary metabolites produced by endophytic fungi have wide applications in pharmacology and agriculture. Isolation, characterisation and evaluation of biological activities of secondary metabolites were carried out from Cochliobolus kusanoi an endophytic fungus of Nerium oleander L. The fungus was identified based on 18S rDNA sequence analysis. There are no reports available on the compounds of C.kusanoi hence, antimicrobial metabolite produced by this fungus was extracted and purified by fractionation using hexane, diethyl ether, dichloromethane, ethyl acetate and methanol. Out of all the solvent fractions, the methanol fraction exhibited better antimicrobial activity which was further purified and characterised as oosporein. Oosporein from C.kusanoi exhibited broad spectrum in vitro antimicrobial, antioxidant and cytotoxic activities. The characterisation and antioxidant activity of oosporein from C. kusanoi are reported for the first time.

Synthesis, structural analysis and solvatochromic behaviour of 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile mesogen

In this communication, we report the synthesis and characterisation of a new luminescent liquid crystalline material, 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile (3). We have confirmed its structure by Fourier transform infrared and 1H nuclear magnetic resonance spectroscopy, elemental analysis and X-ray single crystal diffraction studies. The newly synthesised compound crystallises in a monoclinic system with the space group C2/c and its cell parameters are found to be a = 25.181(4) Å, b = 15.651(4)Å, c = 12.703(19) Å, V = 4880.4 (16) Å, Z = 8. The results indicate that the presence of weak CH … O and CH … N hydrogen bonding as short-range intermolecular interactions are responsible for the formation of its crystal assembly. The measured torsion angle shows the existence of a distorted structure for the molecule wherein 4-butoxyphenylene ring substituent at the fourth position of the central pyridine ring forms a torsion angle χ[C(4), C(3), C(10), C(19)] of 40.55°. Its liquid crystalline behaviour was investigated with the aid of polarised optical microscopy and differential scanning calorimetry. The study reveals that the compound displays a broad nematic phase in the range of 78–112°C. Further, solution phase optical studies indicate that it is a blue light emitter in different non-polar and polar organic solvents at a concentration of 10−5M.

New luminescent 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile: Synthesis, crystal structure, DFT and photophysical studies

In the current communication, we report the synthesis, spectroscopic, crystal structure, DFT and photophysical studies of a new nicotinonitrile derivative, viz. 2-methoxy-6-(4-methoxy-phenyl)-4-p-tolyl-nicotinonitrile (2) as a potential blue light emitting material. The compound 2 was synthesized in good yield via a simple route. The acquired spectral and elemental analysis data were in consistent with the chemical structure of 2. The single crystal study further confirms its three dimensional structure, molecular shape, and nature of short contacts. Its DFT calculations reveal that compound 2 possesses a non-planar structure and its theoretical IR spectral data are found to be in accordance with experimental values. In addition, its UV-visible and fluorescence spectral measurements prove that the compound exhibits good absorption and fluorescence properties. Also, it shows positive solvatochromic effect when the solvent polarity was varied from non-polar to polar.

4'-Cyano-biphenyl-4-yl 7-diethyl-amino-2-oxo-2H-chromene-3-carboxyl-ate.

In the title compound, C27H22N2O4, the dihedral angles between the central benzene ring and the cyanobenzene ring and the 2H-coumarin ring system (r.m.s. deviation = 0.014 Å) are 22.95 (11) and 75.59 (8)°, respectively. Both terminal C atoms of the pendant diethylamino group lie to the same side of the coumarin ring system [deviations = 1.366 (2) and 1.266 (2) Å]. In the crystal, molecules are linked by C—H⋯O and C—H⋯N hydrogen bonds and a C—H⋯π interaction, generating a three-dimensional network.

2-[5-(2-Fluoro­phen­yl)-3-isobutyl-1H-pyrazol-1-yl]benzoic acid

In the title compound, C20H19FN2O2, the dihedral angle between the aromatic rings is 62.1 (1)°, and those between the pyrazole ring and the fluorobenzene and benzoic acid rings are 52.1 (1) and 53.1 (1)°, respectively. In the crystal, molecules are linked into [010] C(7) chains by O—H⋯N hydrogen bonds.

Methyl 4-benz­yloxy-2-hy­droxy­benzoate

In the title compound, C15H14O4, the dihedral angle between the benzene rings is 67.18 (8)°. The Ca—Cm—O—Ca (a = aromatic and m = methylene) torsion angle is 172.6 (3)° and an intramolecular O—H⋯O hydrogen bond generates an S(6) ring. In the crystal, molecules are linked by C—H⋯O hydrogen bonds into zigzag chains propagating in [001] and C—H⋯π interactions also occur.

N-(3-Meth-oxy-benzo-yl)-4-methyl-benzene-sulfonamide.

In the title compound, C15H15NO4S, the dihedral angle between the benzene rings is 88.87 (1)°. In the crystal, adjacent molecules form inversion dimers through pairs of strong N—H⋯O hydrogen bonds, generating R 2 2(8) loops. Two C—H⋯π interactions and an aromatic π–π interaction [centroid–centroid separation = 3.8191 (1) Å] are also observed.

4-Meth-oxy-N-(pyridin-4-ylmeth-yl)-3-(tri-fluoro-meth-yl)benzamide monohydrate.

In the title compound, C15H13F3N2O2·H2O, the dihedral angle between the benzene and pyridine rings is 74.97 (1)°. The –CF3 group attached to the benzene ring is syn to the C=O bond in the adjacent side chain. In the crystal, molecules are linked to one another through the water molecules by strong N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, forming a ladder-type network. The benzamide molecules are also linked to one another through C—H⋯F interactions, forming C(6) chains parallel to the b-axis direction. Aromatic π–π stacking interactions [centroid–centroid separations = 3.7150 (1) and 3.7857 (1) Å] between adjacent pairs of pyridine and benzene rings are also observed, resulting in a three-dimensional architecture are also observed.