Synthesis and carboxylate anion binding studies on cyclic sugar-amino acid hybrids |
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Authors: | Ankita Singh Vipin K Maikhuri Vineet Verma Rajni Johar Chhatwal Deepti Sharma |
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Institution: | 1. Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi, India;2. Maitreyi College, University of Delhi, Delhi, India;3. Sri Venkateswara College, University of Delhi, Delhi, India |
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Abstract: | AbstractHere in, the condensation of boc-glycine with 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitol followed by its boc-deprotection to form 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitolyl bis-glycinate, which in turn on condensation with succinic acid/pyridine-2,6-dicarboxylic acid led to the formation of sugar-amino acid hybrid macrocyclic compounds 4, 6 and debenzylated marocyclic compound 5, having amide bonds that function as efficient host for polar, hydrogen bond acceptors and carboxylate ions. The anion inclusion capability of synthesized macrocylic hosts has been evaluated by the study of their binding with boc-GlyCOOˉ anion as guest through 1H NMR titration studies in CDCl3. The binding constant (Ka) of boc-GlyCOOˉ guest with macrocyclic hosts 4 and 6 involving succinate and pyridine-2,6-dicarboxylate linkers was found to be 9.201?×?103 and 1.437?×?104 M?1, respectively. The higher binding constant was observed in the complex of boc-GlyCOOˉ with pyridine-dicarboxylate containing host may be due to the extra rigidity & suitable conformation attained by the presence of rigid-aromatic dicarboxylate linker. |
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Keywords: | Binding constant carboxylate ion glycine heptitol sugar NMR titration sugar-amino acid based macrocycle |
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