Faculty Publications
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Item (E)-1-(4-Chloro-phen-yl)ethanone semi-carbazone(2009) Fun, H.-K.; Ching Kheng, C.K.; Padaki, M.; Malladi, S.; Isloor, A.M.In the title compound, C9H10ClN3O, the semicarbazone group is approximately planar, with an r.m.s. deviation from the mean plane of 0.054 (1) Å. The dihedral angle between the least-squares planes through the semicarbazone group and the benzene ring is 30.46 (5)°. In the solid state, mol-ecules are linked via inter-molecular N - H?O and N - H?N hydrogen bonds, generating R22(9) ring motifs which, together with R22(8) ring motifs formed by pairs of inter-molecular N - H?O hydrogen bonds, lead to the formation of a seldom-observed mol-ecular trimer. Furthermore, N - H?O hydrogen bonds form R21(7) ring motifs with C - H?O hydrogen bonds, further consolidating the crystal structure. Mol-ecules are linked by these inter-molecular inter-actions, forming two-dimensional networks parallel to (100).Item (E)-1-Phenyl-ethanone semicarbazone(2009) Fun, H.-K.; Yeap, C.S.; Padaki, M.; Malladi, S.; Isloor, A.M.In the title compound, C9H11N3O, the benzene ring is disordered over two positions with refined occupancies of 0.922 (5) and 0.078 (5). The program PLATON [Spek (2009). Acta Cryst. D65, 148-155] recommends the solution in the space group C2/m with a = 7.3050 (3), b = 6.6745 (2), c = 18.3853 (6) Å and ? = 96.986 (2)°. However, the large number of non-extinct reflections needed to be ignored if C2/m is chosen suggested that the space group is incorrect, even though the R values are lower than that for P21/c. The semicarbazone group is essentially planar, with a maximum deviation of 0.046 (1) Å for one of the N atoms. The mean plane of the semicarbazone group forms dihedral angles of 33.61 (8) and 39.1 (9)° with the benzene ring of the major and minor components, respectively. In the crystal structure, mol-ecules are linked by inter-molecular N - H?O hydrogen bonds into extended chains along the c axis. The crystal structure is further stabilized by weak inter-molucular C - H?? inter-actions. © 2009 Fun et al.Item (E)-1-(4-Fluoro-phen-yl)ethan-1-one semicarbazone(2009) Fun, H.-K.; Yeap, C.S.; Padaki, M.; Malladi, S.; Isloor, A.M.In the title compound, C9H10FN3O, the semicarbazone group is nearly planar, with the maximum deviation of 0.044 (1) Å for one of the N atoms. The mean plane of semicarbazone group forms a dihedral angle of 30.94 (4)° with the benzene ring. The mol-ecules are linked into a supra-molecular chain by N - H?O hydrogen bonds formed along the c axis. The crystal structure is further stabilized by weak inter-molucular C - H?? inter-actions; the closest C?Cg contact is 3.6505 (11) Å.Item (E)-1-(4-Bromophenyl)ethan-1-one semicarbazone(2009) Fun, H.-K.; Goh, J.H.; Padaki, M.; Malladi, S.; Isloor, A.M.In the title compound, C9H10BrN3O, the hydrazone portion and aliphatic chain are essentially coplanar [maximum deviation 0.057 (15) Å] and the mean plane makes a dihedral angle of 70.9 (6)° with the benzene ring. The main feature of the crystal structure is the inter-molecular N - H?O hydrogen bond, which links mol-ecules into zigzag chains along the a axis. These chains are further stacked along the b axis. The crystal structure features non-classical inter-molecular C - H?O inter-actions. The crystal studied was a nonmerohedral twin, with a twin ratio of 0.505 (1):0.495 (1).Item 2-(4-Methylanilino)acetohydrazide(2009) Fun, H.-K.; Yeap, C.S.; Malladi, S.; Padaki, M.; Isloor, A.M.In the title mol-ecule, C9H13N9O, the non-hydrogen atoms of the hydrazide group are essentially planar [maximum deviation = 0.028 (1) Å for one of the N atoms]. The mean plane of this group forms a dihedral angle of 83.34 (5)° with the plane of the benzene ring. In the crystal structure, molecules are linked by inter-molecular N - H?O, N - H?N and weak C - H?N hydrogen bonds into a two-dimensional network parallel to the ab plane. Additional stabilization is provided by a weak C - H?? inter-action. © Fun et al. 2009.Item 4-Amino-3-[(4-methoxyphenyl)aminometh-yl]-1H-1,2,4-triazole-5(4H)-thione(2009) Fun, H.-K.; Yeap, C.S.; Malladi, S.; Padaki, M.; Isloor, A.M.The mol-ecule of the title compound, C10H13N 5OS, is approximately planar, the dihedral angle between the triazole and benzene rings being 4.53 (10)°. The amino group adopts a pyramidal configuration. In the crystal structure, molecules are linked into two-dimensional networks parallel to (001) by inter-molecular N - H?S and N - H?N hydrogen bonds. In addition, an S?S short contact of 3.3435 (7) Å is observed. © Fun et al. 2009.Item 4-Amino-3-(1-naphthyloxymethyl)-1H-1,2,4-triazole-5(4H)-thione(2010) Fun, H.-K.; Ching Kheng, C.K.; Vijesh, A.M.; Malladi, S.; Isloor, A.M.In the title compound, C13H12N4OS, the dihedral angle between the triazole and naphthalene ring systems is 67.42 (5)°. In the crystal, adjacent mol-ecules are linked via two pairs of inter-molecular N-H?S inter-actions, forming R 2 2(8) and R 2 2(10) ring motifs. Weak C-H?S inter-actions generate infinite chains along [001] and the structure is further consolidated by C-H?? bonds and aromatic ??? stacking inter-actions [distance between the centroids of the triazole rings = 3.2479 (7) Å].Item 3-Ethyl-6-[3-(4-fluoro-phen-yl)-1H-pyrazol-4-yl]-1,2,4-triazolo[3,4-b][1,3, 4]thia-diazole(2010) Fun, H.-K.; Ching Kheng, C.K.; Malladi, S.; Isloor, A.M.In the title compound, C14H11FN6S, the 1,2,4-triazolo[3,4-b][1,3,4]thia-diazole ring system is essentially planar [maximum deviation = 0.022 (3) Å] and is inclined at dihedral angles of 15.00 (18) and 52.82 (16)° with respect to the pyrazole and phenyl rings. In the crystal, mol-ecules are linked into two-dimensional networks parallel to (100) via inter-molecular N - H?N and weak C - H?N hydrogen bonds. The crystal packing is further consolidated by weak ?-? stacking inter-actions, with a centroid-centroid distance of 3.590 (2) Å. The crystal studied was an inversion twin with a 0.37 (13):0.63 (13) domain ratio.Item Synthesis, characterization and anti-microbial studies of some novel 2,4-disubstituted thiazoles(2010) Vijesh, A.M.; Isloor, A.M.; Prabhu, V.; Ahmad, S.; Malladi, S.In the present study a series of novel 2,4-disubstituted thiazole derivatives containing substituted pyrazole moiety was synthesized by the reaction of 3-Aryl-1H-pyrazole-4-carbaldehyde thiosemicarbazone with 6-Bromo/H-3-(bromoacetyl)-2H-chromen-2-one/phenacyl chloride. Structures of newly synthesized compounds were characterized by spectral studies. New compounds were screened for their antibacterial studies against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The results revealed that compounds 7c, 8e, and 8f having 2,5-dichlorothiophene substituent and 8c, 8d having 2,4-dichlorophenyl substituent showed significant antibacterial activity against all tested microorganisms. © 2010 Elsevier Masson SAS. 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.