Amar A. Hosamani

Synthesis, molecular docking and anti-mycobacterial evaluation of new imidazo(1,2-a)pyridine-2-carboxamide derivatives

New anti-tubercular agents, imidazo[1,2-a]pyridine-2-carboxamide derivatives (5a-q) have been designed and synthesized. The structural considerations of the designed molecules were further supported by the docking study with a long-chain enoyl-acyl carrier protein reductase (InhA). The chemical structures of the new compounds were characterized by IR, (1)H NMR, (13)C NMR, HRMS and elemental analysis. In addition, single crystal X-ray diffraction has also been recorded for compound 5f. Compounds were evaluated in vitro against Mycobacterium tuberculosis H37Rv, and cytotoxicity against HEK-293T cell line. Amongst the tested compounds 5j, 5l and 5q were emerged as good anti-tubercular agents with low cytotoxicity. The structure-anti TB activity relationship of these derivatives was explained by molecular docking.

Synthesis, crystal structures, biological screening and electrochemical analysis of some salen-based transition metal complexes

A new series of transition metal complexes with (1) Mn(III), (2) Co(II), (3) Ni(II) and (4) Cu(II) have been synthesized by the reaction of [6,6′-((1E,1′E)-(propane-1,3-diylbis(azanylylidene))bis(methanylylidene))bis(5-isopropyl-2-methylphenol)] with suitable metal salts. The synthesized complexes have been characterized by elemental analysis and spectroscopic techniques. The results of single crystal structures show that the metal is bonded to the ligand through the phenolic oxygens and imino nitrogens. Synthesized complexes have been evaluated for antibacterial activity and antioxidant activity, which shows considerable results.

Charge density analysis of metformin chloride, a biguanide anti-hyperglycemic agent

The experimental charge density analysis of the anti-hyperglycemic agent metformin chloride with high-resolution X-ray diffraction data at low temperature (100 K) has been performed and these experimental results were compared with that derived from the corresponding periodic theoretical calculations at the B3LYP/6-31G** level of theory. The experimental and theoretical multipolar charge-density analyses of metformin chloride have been accomplished in order to understand its structural and electronic properties. The C and N atoms of the molecular backbone adopt a near trigonal geometry due to the occurrence of extensive delocalization/resonance of C—N bonds, as confirmed by topological analysis and also found by Natural Resonance Theory calculations performed in the isolated metformin cation. The molecule contains six C—N bonds and the topological bond order analysis shows that four bonds have bond orders close to 4/3 and two bonds can be considered as single. The analysis of numerical parameters of the valence shell charge concentration reports that the N3 atom, which forms two bonds with C atoms, possesses one non-bonding valence-shell charge concentration (VSCC) in the direction of the electron lone pair. Among the intermolecular interactions of the chloride atom with the H—C and H—N atoms, eight have been found to be shorter than the sum of van der Waals radii. The analysis of contacts on the Hirshfeld surface reveals that the H—N⋯Cl hydrogen bonds are enriched (over-represented) and act as the driving force in the crystal packing formation. The metformin cations form favorable electrostatic interactions with the chloride anions which have globally a stronger energy than the unfavorable cation/cation interactions.

Synthesis, characterizations, biological activities and docking studies of novel dihydroxy derivatives of natural phenolic monoterpenoids containing azomethine linkage

In the present work, we report the synthesis of six new azomethine linkage containing dihydroxy derivatives of carvacrol, thymol, and eugenol. All the synthesized derivatives have been characterized by spectroscopic techniques and their structures were confirmed by X-ray single crystallography. Synthesized derivatives were screened for anti-oxidant activity using DPPH radical scavenging assay, and anticancer activity by using SRB assay against pancreatic cancer with MIAPaCa-2 and colon cancer with HCT-15 cell lines. The molecular docking studies of all the synthesized derivatives were performed on cyclooxygenases (COX-2) protein enzyme. In the anti-oxidant test, the values of EC50 indicated that all the compounds show excellent anti-oxidant potency, and similarly the GI50 values in anticancer tests indicated that most of the compounds possess good anticancer efficacy. The overall docking score suggested that all the synthesized compounds exhibit good binding affinity towards cyclooxygenases (COX-2) protein enzyme.Graphical Abstract

Crystal structure of 2-(4-chloro­phen­yl)-3-(4-meth­oxy­phen­yl)-3-(methyl­sulfanyl)­acrylo­nitrile

In the title compound, C17H14ClNOS, the aromatic rings are inclined to one another by 64.22 (9)°. The acrylonitrile group (C=C—C N) is planar to within 0.003 (2) Å, with the S atom and the methyl C atom displaced from this plane by 0.2317 (6) and −0.637 (2) Å, respectively. In the crystal, molecules are linked via pairs of C—H⋯π interactions, forming inversion dimers. There are no other significant intermolecular interactions present.

Synthesis, characterization and determination of absolute structures of palladium complexes of novel chiral acyclic tellurated Schiff base ligands

Enantiomerically pure chiral hybrid organotellurium ligands (R)-L1H, (S)-L2H and (R)-L3H have been synthesized via condensation of the chiral β-organotellurated amines 2a, 2b and 2c, respectively, with salicylaldehyde. When these chiral acyclic tellurated Schiff base ligands reacted with Na2PdCl4 in a 1 : 1 molar ratio, they afforded the corresponding orange-red asymmetric complexes [Pd(L1–3)Cl] (1–3). All these compounds were characterized by elemental analysis, polarimetry, and 1H, 13C{1H} NMR and FT-IR spectroscopies. The absolute structures of the complexes 1 and 2 were determined by single crystal X-ray diffraction, and the complexes 1 and 2 crystallized in the hexagonal and orthorhombic crystal systems with the space groups P65 and P212121, respectively. The characterisation data showed that the ligands coordinated in the deprotonated tridentate (Te, N, O−) mode and acquired a square planar geometry around the central palladium(II) ion along with a monodentate chloro (Cl−) in 1–3. The Pd–Te, Pd–Cl, Pd–O and Pd–N bond lengths found were 2.5008(9), 2.3286(19), 2.037(6) and 2.009(6) A, respectively, in 1 and 2.497(2)/2.506(3), 2.293(6)/2.326(6), 2.035(15)/2.030(2) and 1.949(17)/2.010(2) A, respectively, in 2. There was intermolecular CH⋯Cl [2.81–2.96 A] and CH⋯O [2.40–2.64 A] hydrogen bonding in 1 and 2, which resulted in supramolecular structures. The Te⋯Cl [3.309–3.710 A] secondary interactions resulted in the helical structure of 1 and dimeric structure of 2 with a short Pd⋯Pd [3.500(1) A] distance. The Flack parameters (x) of 1 [0.02(3)] and 2 [0.024(12)] confirmed their absolute configurations.