Infrared and 1H NMR studies of hydrogen bonding in N-(2-amino-2-deoxy-β-D-glucopyranoside)-N′-carbamoyl-L-amino acid esters

✍ Scribed by Monika Plass; Iwona Wawer; Boguslawa Piekarska-Bartoszewicz; Andrzej Temeriusz

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 138 KB
• Volume: 10
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199710)10:10<747::aid-poc945>3.0.co;2-j

✦ Synopsis

Ureido 2-deoxy-␤-D-glucopyranosides with seven different amino acid ester residues were studied by means of IR and 1 H NMR spectroscopy. The H-D exchange rates increase in the order L-Val <L-Leu <L-Ala < Gly for both NH protons; however, the exchange rate at N-1-H (linked to the glucopyranoside) is significantly faster than that at N-3-H (at the amino acid residue). The analysis of IR spectra in the region of the NH stretching vibrations shows, in agreement with other investigations, that the signals at 3454, 3423 and 3355 cm Ϫ 1 are due to the free and the intramolecular associated NH groups forming a five-and seven-membered ring, respectively. It was found that the C 7 associated ring is formed by hydrogen bonding between the N-1-H function and the C--O of the acetyl group at the C-3 position in the glucopyranoside. The N-3-H group is involved in a hydrogen bond with the C--O function of the ester group protecting the amino acid residue. Furthermore, it was found that the ureido sugar with L-Val exhibits a stronger C 7 hydrogen bond than the other amino acid residues. This result conforms with the lowest H-D exchange rate at the N-1 position of this compound. Steric effects resulting in the shielding of this hydrogen bond against OD attack are considered as a reason for this peculiarity.