Manpreet Kaur

5,7,12,14-Tetra­hydro-5,14:7,12-bis­([1,2]benzeno)­penta­cene-6,13-diol di­methyl­formamide disolvate

The crystal lattice of the title compound, C34H22O2·2C3H7NO, at 173u2005K has monoclinic (P21/n) symmetry. Molxadecules are located on crystallographic centers of symmetry and have approximate non-crystallographic mmm symmetry, indicating that in solution the chemical and spectroscopic behavior would be that of a D2h molxadecule. The compound has applications in gas-separation membranes fabricated from polymers of intrinsic microporosity (PIM). The compound is the product of reduction of the corresponding quinone by Na2S2O4 in DMF/NaHCO3.

Benzimidazolyl based Schiff base palladium complex in an ionic liquid: an effective combination for Suzuki coupling

Abstract A new benzimidazole based Pd(II) Schiff base complex was prepared and its catalytic activity was evaluated for Suzuki cross-coupling reactions in ethyl-methyl imidazolium hexafluorophosphate [EMIM PF6] ionic liquid at ambient temperature. The system provides a stable and reusable method for coupling reactions. Optimization for suitable reaction conditions were studied with respect to the effect of catalyst concentration, effects of additives, solvent and substituents on boronic acid. Good to excellent yields were achieved using a modest amount of the catalyst. The reaction time was less and the yield was more compared to previously reported results. In addition, the catalyst can be easily reused and recycled for six times without much loss in activity; this is an example of sustainable and green methodology.

Crystal structures of three 3-chloro-3-methyl-2,6-di­aryl­piperidin-4-ones

The syntheses and crystal structures of 3-chloro-3-methyl-r-2,c-6-diphenylpiperidin-4-one and two of its derivatives are described. In each structure, the piperidine ring adopts a chair conformation. In the crystals, molecules are linked into C(6) chains by weak N—H⋯O hydrogen bonds and C—H⋯π interactions are also observed.

3-Chloro- r -2, c -6-bis(4-fluorophenyl)-3-methylpiperidin-4-one

The title compound, C18H16ClF2NO, contains one independent molxadecule in the asymmetric unit, with the piperidin-4-one ring adopting a slightly distorted chair conformation and an equatorial orientation of all the substituents except chlorine. A single weak interxadmolecular C—H⋯O interxadaction influences the crystal packing, forming infinite one-dimensional zigzag chains along the a axis. The structure was refined as a two-component inversion twin.

Crystal structure of 5,7,12,14-tetra­hydro-5,14:7,12-bis­([1,2]benzeno)­penta­cene-6,13-dione

5,7,12,14-Tetrahydro-5,14:7,12-bis([1,2]benzeno)pentacene-6,13-dione, used as a precursor in the synthesis of polymers of intrinsic microporosity (PIM) membranes, recrystallizes from DMF.

Reactions between arylhydrazinium chlorides and 2‐chloroquinoline‐3‐carbaldehydes: molecular and supramolecular structures of a hydrazone, a 4,9‐dihydro‐1H‐pyrazolo[3,4‐b]quinoline and two 1H‐pyrazolo[3,4‐b]quinolines

Hydrazone derivatives exhibit a wide range of biological activities, while pyrazolo[3,4-b]quinoline derivatives, on the other hand, exhibit both antimicrobial and antiviral activity, so that all new derivatives in these chemical classes are potentially of value. Dry grinding of a mixture of 2-chloroquinoline-3-carbaldehyde and 4-methylphenylhydrazinium chloride gives (E)-1-[(2-chloroquinolin-3-yl)methylidene]-2-(4-methylphenyl)hydrazine, C17H14ClN3, (I), while the same regents in methanol in the presence of sodium cyanoborohydride give 1-(4-methylphenyl)-4,9-dihydro-1H-pyrazolo[3,4-b]quinoline, C17H15N3, (II). The reactions between phenylhydrazinium chloride and either 2-chloroquinoline-3-carbaldehyde or 2-chloro-6-methylquinoline-3-carbaldehyde give, respectively, 1-phenyl-1H-pyrazolo[3,4-b]quinoline, C16H11N3, (III), which crystallizes in the space group Pbcn as a nonmerohedral twin having Z = 3, or 6-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinoline, C17H13N3, (IV), which crystallizes in the space group Roverline{3}. The molecules of compound (I) are linked into sheets by a combination of N-H...N and C-H...π(arene) hydrogen bonds, and the molecules of compound (II) are linked by a combination of N-H...N and C-H...π(arene) hydrogen bonds to form a chain of rings. In the structure of compound (III), one of the three independent molecules forms chains generated by C-H...π(arene) hydrogen bonds, with a second type of molecule linked to the chains by a second C-H...π(arene) hydrogen bond and the third type of molecule linked to the chain by multiple π-π stacking interactions. A single C-H...π(arene) hydrogen bond links the molecules of compound (IV) into cyclic centrosymmetric hexamers having overline{3} (S6) symmetry, which are themselves linked into a three-dimensional array by π-π stacking interactions.

Synthesis, structures and antimicrobial activity of copper derivatives of N-substituted imidazolidine-2-thiones: unusual bio-activity against Staphylococcus epidermidis and Enterococcus faecalis

The main objective of this study was to explore the antimicrobial activity of several copper(I) complexes with N,S-donor thio-ligands against Gram positive bacteria, namely Staphylococcus aureus (MTCC 740), Staphylococcus epidermidis (MTCC 435), and Enterococcus faecalis (MTCC 439), Gram negative bacteria, Shigella flexneri (MTCC 1457) and Escherichia coli (MTCC 119), and yeast, Candida tropicalis (MTCC 230). New copper complexes were prepared from copper(I) halides and imidazolidine-2-thiones (L-NR, R = Et; Prn; Bun; Ph) with triphenylphosphine as a co-ligand. The complexes are mononuclear, [CuX(L-NR)(PPh3)2] (X, R: Cl, Prn, 1; Br, Prn, 2; Cl, Bun, 3; I, Bun, 4; I, Ph, 6) and [CuBr(L-NPh)2(PPh3)] 5, and halogen-bridged dinuclear, [Cu2(μ-X)2(L-NR)2(PPh3)2] (Br, Et, 7; Cl, Prn, 8; Br, Prn, 9; I, Prn, 10; Br, Ph, 11; I, Ph, 12). These complexes were characterized using analytical data, IR, 1H/13C-NMR spectroscopy, single crystal X-ray crystallography, electron spray ionization mass spectrometry (ESI-MS) and techniques for antimicrobial study (agar diffusion, agar dilution, MTT assay). All of the complexes are found to be bactericidal against Staphylococcus aureus. The most significant outcome of this investigation is that several complexes have shown significant activity against Staphylococcus epidermidis and Enterococcus faecalis, which is higher than that of the standard drug Gentamicin. Finally, these complexes were nearly inactive against Shigella flexneri, Escherichia coli and yeast Candida tropicalis.

One-Pot Double [3 + 2] Cycloadditions for Diastereoselective Synthesis of Pyrrolidine-Based Polycyclic Systems

Sequential inter- and intramolecular [3 + 2] cycloadditions of azomethine ylides are developed for the one-pot and diastereoselective synthesis of highly condensed heterocyclic systems containing pyrrolidine and up to seven stereocenters. It has high synthetic efficiency and operational simplicity, and only water was generated as a byproduct.

1-[(1-Butyl-1H-1,2,3-triazol-5-yl)meth­yl]-3-methyl­quinoxalin-2(1H)-one

In the title compound, C16H19N5O, the quinoxaline and triazole rings are almost orthogonal, inclined to one another at an angle of 79.8u2005(3)°. A weak intraxadmolecular C—H⋯O interxadaction locks the conformation of the molxadecule. The crystal packing features weak interxadmolecular C—H⋯O and C—H⋯N interxadactions, which form chains along the b-axis direction. In addition, weak C—H⋯π interxadmolecular interxadactions further influence the crystal packing.

7-Bromo-1,4-bis­(prop-2-yn­yl)pyrido[2,3-b]pyrazine-2,3(1H,4H)-dione

In the title compound, C13H8BrN3O2, the pyrido-pyrazine fused-ring system is essentially planar (r.m.s. deviation = 0.061u2005A). The prop-2-ynyl moieties are twisted away from the ring system in opposite directions. In the crystal, a single weak C—H⋯O interxadaction generates [010] chains and aromatic π–π stacking interxadactions between the pyridine rings are observed.