Preparation and structural characterization of N-glycated amino acid and linear or cyclic dipeptides containing the 6-amino-6-deoxy-1,2:3,4-di-O-isopropylidene-α-d-galactopyranose moiety
✍ Scribed by Mare Čudić; Biserka Kojić-Prodić; Vjekoslav Milinković; Jaroslav Horvat; Štefica Horvat; Mikael Elofsson; Jan Kihlberg
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 779 KB
- Volume
- 287
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
N-Glycated derivatives of glycine, glycylglycine, and 2,5-piperazinedione, containing the 6-deoxy-l,2:3,4-di-O-isopropylidene-a-D-galactos-6-yl moiety, were synthesized and studied by X-ray crystallography and NMR spectroscopy. The crystal structures of N-(6-deoxy-l,2:3,4-di-Oisopropylidene-a-D-galactos-6-yl)glycine (2), its glycylglycine analogue (3), and 2,5-piperazinedione congener (4) were determined. The crystals of 2 are monoclinic; space group P2 t with a = 10.5098(5), b = 5.7632(5), c = 13.0938(7) A, /3 = 90.245(5) °, Z = 2. The compounds 3 and 4 crystallized in the orthorhombic space group P21212 t with a=5.3429(9), b= 15.1484(4), c = 22.853(2) ,~, Z= 4 (3) and a = 28.69( 6), b = 15.478(3), c = 15.504(2) A, Z = 4 (4). In the solid state the a-D-galactopyranose moiety of 2 and 3 existed in the twisted °T 2 conformation, whereas in 4 a transition state between °T 2 and °S 2 was recorded. ~ H NMR spectroscopy revealed that the conformation in solution for the galactopyranose moiety of compounds 2-4 closely resembled that found in the crystals.