Selectivity control during the solid supported protic acids catalysed synthesis of 1,2-disubstituted benzimidazoles and mechanistic insight to rationalize selectivity
Selectivity control during the solid supported protic acids catalysed synthesis of 1,2-disubstituted benzimidazoles and mechanistic insight to rationalize selectivity
Reduced Schiff bases with a common p-nitro-o-phenylenediamine moiety have been synthesised and their structures have been characterized by single-crystal structural analysis. Schiff bases having self-complementary H-bond donors and H-bond acceptors can form a âscissorsâ like structure through intermolecular H-bonding interaction. Reduced Schiff bases interact with biologically important dihydrogenphosphate ion and form stable complexes. Furthermore, dihydrogenphosphate and water form an unprecedented self-assembled dihydrogenphosphateâwater [H2PO4·H2O]nnâ 1D supramolecular polymer upon complexation with reduced Schiff bases.
Design, synthesis, and enzyme kinetics of novel benzimidazole and quinoxaline derivatives as methionine synthase inhibitors
作者:Hosam Elshihawy、Mohamed A. Helal、Mohamed Said、Mohamed A. Hammad
DOI:10.1016/j.bmc.2013.10.052
日期:2014.1
Methionine synthase catalyzes the transfer of a methyl group from 5-methyltetrahydrofolate to homocysteine, producing methionine and tetrahydrofolate. Benzimidazole and deazatetrahydrofolates derivatives have been shown to inhibit methionine synthase by competing with the substrate 5-methyltetrahydrofolate. In this study, a novel series of substituted benzimidazoles and quinoxalines were designed and assessed for inhibitory activity against purified rat liver methionine synthase using a radiometric enzyme assay. Compounds 3g, 3j, and 5c showed the highest activity against methionine synthase (IC50: 20 mu M, 18 mu M, 9 mu M, respectively). Kinetic analysis of these compounds using Lineweaver-Burk plots revealed characteristics of mixed inhibition for 3g and 5c; and uncompetitive inhibition for 3j. Docking study into a homology model of the rat methionine synthase gave insights into the molecular determinants of the activity of this class of compounds. The identification of these drug-like inhibitors could lead the design of the next generation modulators of methionine synthase. (C) 2013 Elsevier Ltd. All rights reserved.
Reusable Amine-Based Structural Motifs for Green House Gas (CO<sub>2</sub>) Fixation
A series of compounds with an amine based structural motif (ASM) have been synthesized for efficient atmospheric CO2 fixation. The H-bonded ASM bicarbonate complexes were formed with an in situ generated HCO3- ion. The complexes have been characterized by IR, C-13 NMR, and X-ray single-crystal structural analysis. ASM bicarbonate salts have been converted to pure ASMs in quantitative yield under mild conditions for recycling processes.