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Item Synthesis, characterization and nonlinear optical properties of 2-[(E)-2-(4-ethoxyphenyl)ethenyl]-1-methylquinolinium 4-substitutedbenzenesulfonate compounds(2010) Ruanwas, P.; Kobkeatthawin, T.; Chantrapromma, S.; Fun, H.-K.; Philip, R.; Smijesh, N.; Padaki, M.; Isloor, A.M.In the present investigation, 2-[(E)-2-(4-ethoxyphenyl)ethenyl]-1-methylquinolinium 4-substituted benzenesulfonate (X = CH3 (1), X = OCH3 (2), X = Cl (3), X = Br (4)) have been synthesized and characterized by 1H NMR, UV-Vis and FT-IR spectroscopy methods. In addition compound 3 was also characterized by single crystal X-ray diffraction (XRD) and found that it crystallized out in the monoclinic space group P21 with cell parameters, a = 9.8072(9) , b = 6.4848(5) , c = 19.4405(16) , ? = 90 , ? = 103.421(5) , ? = 90 , z = 2 and V = 1202.61(17) 3. The nonlinear optical absorption of the samples has been studied at 532 nm using 5 ns laser pulses, employing the open-aperture z-scan technique. It is found that some of the samples are potential candidates for optical limiting applications. 2009 Elsevier B.V. All rights reserved.Item Synthesis and biological evaluation of aminoketones(2010) Sankappa, Rai, U.; Isloor, A.M.; Shetty, P.; Isloor, N.; Malladi, S.; Fun, H.-K.A three-component Mannich reaction of different ketones with aromatic aldehydes and different amines in microwave irradiation under solvent free condition afforded corresponding ?-amino carbonyl compounds in excellent yields. This method proved as a novel and improved modification of the reported three-component Mannich reaction in terms of milder reaction conditions, reaction times, clean reaction profiles, very small quantity of catalyst and simple workup procedure. Newly synthesized ?-aminoketones were characterized by spectral studies. Structure of compound 4a was also confirmed by single-crystal X-ray analysis. All the compounds were screened for their antimicrobial activity by MIC method. Few of the molecules were found to be biologically potent. 2010 Elsevier Masson SAS. All rights reserved.Item Redetermination of methyl 3,4-O-isopropyl-idene-?-D-fucopyran-oside monohydrate(2009) Fun, H.-K.; Jebas, S.R.; Rai, S.; Shetty, P.; Isloor, A.M.In the title compound, C10H18O5 H2O, the fucopyran-oside ring adopts a chair conformation. The crystal packing is stabilized by inter-molecular O - H?O and C - H?O hydrogen bonds together with intra-molecular O?O [2.2936 (8) ] and inter-molecular O?O [2.7140 (8)-2.829 (3) ] short contacts. The mol-ecules are linked together to form an infinite chain along the a axis. This structure has been solved previously but with no R-values [Spiers (1931). Z. Kristallogr. Kristallgeom. Kristallphys. Kristallchem. 78, 101].Item Methyl 2,6-bis-[(5-bromo-4,6-dimethoxypyrimidin-2-yl)oxy]benzoate(2010) Fun, H.-K.; Goh, J.H.; Rai, S.; Isloor, A.M.; Shetty, P.In the title compound, C20H18Br2N 4O8, the inter-planar angle of the pyrimidine rings is 75.1 (2) . The central benzene ring is inclined at inter-planar angles of 66.5 (2) and 71.9 (2) with respect to the two pyrimidine rings. In the crystal structure, adjacent molecules are connected into two-molecule-thick arrays parallel to the bc plane via short Br?Br [3.5328 (12) ] and Br?O [3.206 (3) and 3.301 (4) ] inter-actions. A weak inter-molecular ?-? aromatic stacking inter-action [centroid-centroid distance = 3.526 (3) ] is also observed.Item Methyl 2,6-bis-[(5-chloro-4,6-dimethoxypyrimidin-2-yl)oxy]benzoate(2010) Fun, H.-K.; Goh, J.H.; Rai, S.; Isloor, A.M.; Shetty, P.In the title compound, C20H18Cl2N 4O8, the two pyrimidine rings are inclined at dihedral angles of 66.68 (5) and 71.91 (6) with respect to the central benzene ring. In the crystal structure, inter-molecular C-H?N hydrogen bonds link neighbouring molecules into a ribbon-like structure along the b axis. The ribbons are inter-connected into a two-dimensional network parallel to the bc plane by short inter-molecular Cl?Cl [3.4427 (6) ] and Cl?O [3.1420 (9) and 3.1750 (11) ] inter-actions. The crystal structure is further stabilized by inter-molecular ?-? inter-actions [centroid-centroid distance 3.4552 (8) ] involving the pyrimidine rings.Item Novel chromeno [2,3-b]-pyrimidine derivatives as potential anti-microbial agents(2010) Sankappa, Rai, U.; Isloor, A.M.; shetty, P.; Vijesh, A.M.; Prabhu, N.; Isloor, S.; Thiageeswaran, M.; Fun, H.-K.An efficient, microwave irradiated synthesis of novel chromeno[2,3-b]-pyrimidine derivatives was carried out. 2-Amino-3,4-dihydro-2H-chromene-3-carbonitrile was converted into imine using N,N-Dimethylacetaldehyde dimethylacetal to give the core intermediate, which was used for the preparation of chromenopyrimidine library, using acetic acid and different amine in microwave irradiation for 5 min. Structures of newly synthesized compounds were confirmed by spectral studies. Compound 6g was characterized by single crystal X-ray analysis. All the compounds were also screened for their anti-microbial activity. Few of the compounds are found to be potential antimicrobials. 2010 Elsevier Masson SAS. All rights reserved.Item N-[(4-Amino-5-sulfanylidene-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl] -4-methylbenzamide(2010) Fun, H.-K.; Yeap, C.S.; Mange, Y.; Isloor, A.M.; Hegde, C.In the title compound, C11H13N5OS, the dihedral angle between the triazole ring and the benzene ring is 84.21 (7) . The amino group adopts a pyramidal configuration. An intra-molecular N - H?O hydrogen bond stabilizes the molecular structure and generates an S(8) ring. In the crystal, molecules are linked by inter-molecular N - H?O, N - H?S, N - H?N and C - H?S hydrogen bonds into layers lying parallel to the bc plane. The crystal structure is further stabilized by aromatic ?-? stacking interactions [centroid-centroid distance = 3.3330 (7) ].Item N-(1-Naphth-yl)-10H-9-oxa-1,3-diaza-anthracen-4-amine(2009) Fun, H.-K.; Chantrapromma, S.; Rai, S.; Shetty, P.; Isloor, A.M.In the mol-ecule of the title compound, C21H15N 3O, the 10H-9-oxa-1,3-diaza-anthracene ring system is slightly bent, with dihedral angles of 3.99 (6) and 4.80 (6) between the pyran ring and the pyrimidine and benzene rings, respectively. This ring system makes a dihedral angle of 85.23 (3) with the naphthalene plane. In the crystal packing, mol-ecules are linked by N - H?N hydrogen bonds into chains along the a axis and these chains are stacked along the b axis. The crystal is further stabilized by weak C - H?N and C - H?? inter-actions.Item N,N-Bis(2,6-difluorobenzyl)-1,3,4-thia-diazol-2-amine(2009) Fun, H.-K.; Liew, W.-C.; Chandrakantha, B.; Isloor, A.M.In the title compound, C16H11F4N 3S, the dihedral angles between the thia-diazole ring and the difluorobenzyl rings are 81.95 (7) and 81.96 (7) , whereas the dihedral angle between the difluorobenzyl rings is 11.41 (7) . In the crystal structure, C - H?N and C - H?F inter-actions link the molecules into two-dimensional arrays parallel to the bc plane. Fun et al. 2009.Item Ethyl 1-tert-butyl-5-phenyl-1H-pyrazole-4-carboxylate(2010) Fun, H.-K.; Quah, C.K.; Chandrakantha, B.; Isloor, A.M.; Shetty, P.In the title compound, C16H20N2O 2, the pyrazole ring is essentially planar [maximum deviation = 0.008 (2) ] and is inclined at an angle of 82.82 (10) with respect to the phenyl ring. The crystal packing is consolidated by pairs of intermolecular C-H?O hydrogen bonds, which link the molecules into centrosymmetric dimers stacked along the a axis.