Showing papers by "Bachcha Singh published in 2010"
TL;DR: The mesomorphic properties of these compounds were studied by differential scanning calorimetry and polarizing microscopy as mentioned in this paper, where m = 6, 7, 8, 9, 10, 11, 12, 14, and 16 have been synthesized.
Abstract: A new series of 3-[4-(4′-alkoxybenzoyloxybenzylidene)amino]-1,2,4-triazines, C3H2N3N˭CHC6H4OCOC6H4OCmH2m + 1 where m = 6, 7, 8, 9, 10, 11, 12, 14, and 16 have been synthesized. These compounds have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR spectroscopy. Mesomorphic properties of these compounds were studied by differential scanning calorimetry and polarizing microscopy. The mesomorphic nature of these compounds is dependent on the alkoxy chain length. The compounds (m = 6, 7) do not exhibit mesomorphism while the compounds (m = 8, 9, 11, 12, 14) show a monotropic nematic mesophase in cooling cycle. The 3-[4-(4′-decyloxybenzoyloxybenzylidene)amino]-1,2,4-triazine displays an enantiotropic nematic mesophase and the hexadecyloxy compound exhibits the smectic A mesophase.
14 citations
TL;DR: Among the eight compounds evaluated for their antiproliferative activity in vitro, L(8) produced good activity against the cancer cell lines A549 and PC-3 and was mainly through the hepatobiliary system.
Abstract: The synthesis of eight ligands by using 2-amino benzimidazole with different mono/bis aldehydes is described herein. The final products were characterized by spectral techniques such as FT-IR, 1H NMR, and EI-Mass. The structure–activity relationships of the benzimidazole derivatives are also reported. Studies on the complexation of the ligands with 99mTc were optimized by using stannous tartrate as reducing agent under various reaction conditions. The radiochemical stability was ≥95% for all the complexes, and they were to be stable for 12–14 hours in serum. Most of the ligands showed fast blood clearance. Biodistribution studies of the 99mTc complexes of these ligands showed no significant uptake in the brain or in the heart, and the clearance was mainly through the hepatobiliary system. Among the eight compounds evaluated for their antiproliferative activity in vitro, L8 produced good activity against the cancer cell lines A549 and PC-3.
14 citations
TL;DR: The resulting models could act as an efficient strategy for estimating the hypoxic conditions through imaging and provide some insights into the structural features related to the biological activity of these compounds.
Abstract: Copper(II) bis(thiosemicarbazone) are very useful for blood flow and hypoxic imaging. The aim of this study was to identify structure-activity relationships (SARs) within a series of analogues with different substitution patterns in the ligands, in order to design improved hypoxia imaging agents and elucidate hypoxia selectivity mechanisms. Genetic algorithms (GAs) were used to develop specific copper metal-ligand force field parameters for the MM3 force-field calculations. These new parameters produced results in good agreement with experiment and previously reported copper metal-ligand parameters. A successful quantitative SAR (QSAR) for predicting the several classes of Cu(II)-chelating ligands was built using a training set of 21 Cu(II) complexes. The QSAR exhibited a correlation between the predicted and experimental test set. The QSAR preformed with great accuracy; r(2) = 0.95 and q(2) = 0.90 utilizing a leave-one-out cross-validation with multiple linear regression analysis to find correlation between different calculated molecular descriptors of these complexes. The final QSAR mathematical models were found as the following: Log P = {3.01698 (+/-0.0590)} - LUMO {0.1248 (+/-0.068)} + MR {0.3219 (+/-0.086)} n = 21 |r| = 0.972 s = 0.188 F = 98.102 The resulting models could act as an efficient strategy for estimating the hypoxic conditions through imaging and provide some insights into the structural features related to the biological activity of these compounds.
4 citations
TL;DR: A new series of mesogenic unsymmetrical azines, N-(o-hydroxybenzylidene)-N′-(4-n-alkoxybenzoyloxy benzylidsene)azines, HOC6H4CH˭N-N˭CHC 6H4OCOC6h4O CmH2m+1 (m = 7, 8, 9, 10, 11, 12, 14, and 16) have been prepared as discussed by the authors.
Abstract: A new series of mesogenic unsymmetrical azines, N-(o-hydroxybenzylidene)-N′-(4-n-alkoxybenzoyloxybenzylidene)azines, HOC6H4CH˭N-N˭CHC6H4OCOC6H4O CmH2m + 1 (m = 7, 8, 9, 10, 11, 12, 14, and 16) have been prepared. They have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR (Nuclear Magnetic Resonance) spectra. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The azines m = 7, 10, and 14 exhibit features of enantiotropic nematic (N) mesophase whereas azines m = 8, 11 exhibit features of a monotropic nematic phase. The azines m = 9, 12, and 16 do not exhibit mesogenic nature.
4 citations
TL;DR: A new series of 2,5-bis(4n-alkoxybenzoyloxy)-3,6-dichloro-1,4-benzoquinones, C6Cl2O2(OOCC6H4OR)2 Cu(CH3COO)2·H2O where R˭CmH2m+1 and m ǫ = 6,7,8,9,10, 11,12,14, and 16 have been synthesized as discussed by the authors.
Abstract: A new series of 2,5-bis(4-n-alkoxybenzoyloxy)-3,6-dichloro-1,4-benzoquinones, C6Cl2O2(OOCC6H4OR)2 and their copper (II) compounds, C6Cl2O2(OOCC6H4OR)2 Cu(CH3COO)2·H2O where R˭CmH2m+1 and m = 6,7,8,9,10, 11,12,14, and 16 have been synthesized. The compounds have been characterized by elemental analyses, fourier transform infrared (FTIR) far IR, 1H, and 13C NMR spectra. The UV-Visible, electron spin resonance (ESR), and magnetic susceptibility studies of the copper compounds have also been made. Mesomorphic properties of these compounds were studied by differential scanning calorimetry and polarizing microscopy. The mesomorphic nature of these compounds depends on the alkoxy chain length. The compounds (m = 6, 7, 8, 14) exhibit the nematic mesophase. Compound (m = 9)shows a nematic mesophase in heating cycle and both a nematic and a smectic A mesophase in the cooling cycle, whereas compound (m = 10) shows enantiotropic nematic and smectic A mesophases. Compound (m = 11) shows a monotropic smectic A mesophas...
1 citations
TL;DR: In this article, a new series of 2,5-bis[4n-alkoxybenzoyloxy-(4-benzoyleloxy)]-3,6-dichloro-1, 4-benzoquinones, C6Cl2O2(OCOC 6H4OCOC6H4OR)2, where R = CmH2m+1 and m = 7, 8, 9, 10, 11, 12, 14, and 16, have been synthesized.
Abstract: A new series of 2,5-bis[4-n-alkoxybenzoyloxy-(4-benzoyloxy)]-3,6-dichloro-1,4-benzoquinones, C6Cl2O2(OCOC6H4OCOC6H4OR)2, where R = CmH2m + 1 and m = 7, 8, 9, 10, 11, 12, 14, and 16, have been synthesized. These compounds have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR spectra. Mesomorphic properties of these compounds were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The mesomorphic nature of these compounds depends on the alkoxy chain length. The compounds (m = 7, 8, 9, 10) exhibit a monotropic nematic mesophase in cooling cycle, while the compounds (m = 11, 12, 14, and 16) show no mesogenic behavior in both heating and cooling cycles. The intermolecular interactions play a vital role in the mesogenic nature of these compounds. In higher homologues of the series the intermolecular interactions become more prominent leading to loss in mesogenic nature.