1H NMR Study of Hydrogen Bonding and Hydrogen to Deuterium Isotope Exchange in Ureido Sugars |
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| Authors: | Andrzej Wawer Iwona Wawer Boguslawa Piekarska-Bartoszewicz Andrzej Temeriusz |
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| Institution: | Department of Chemistry , Warsaw University , Warszawa 02-093, Pasteura 1, Poland |
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| Abstract: | Abstract The acidic properties of ureido NH protons in two new derivatives of methyl 3,4,6-triacetyl-2-deoxy-β-D-glucopyranoside and i-butylamine (1) and L-leucine (2) were studied by 1H NMR. Stronger influence of polar aprotic solvents, more effective interaction with nitroxyl radical and faster H/D exchange indicate that N1'-H proton which is proximate to the glucopyranose ring is more acidic than N3'-H one in both ureido sugars, this conclusion was supported by semi-empirical AM1 calculation. Hydrogen to deuterium exchange rates are 1.2 x 10?2 to 5.5x 10?3 M?1 min?l. Significantly slower exchange of N3'-H proton standing by Leu residue in 2 can be explained by the existence of internal H-bonds. |
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| Keywords: | 1H NMR H/D isotopic exchange ureido sugars |
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