Structural analysis of 6-S-(benzoxazol-2-yl)-6-deoxy1,2:3,4-di-O-isopropylidene-6-thio-α-d-galactopyranose by means of X-ray diffraction, high resolution NMR spectroscopy, and molecular modelling

✍ Scribed by Miles T. Lakin; Nadine Mouhous-Riou; Christelle Lorin; Patrick Rollin; Jan Kroon; Serge Pérez

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 517 KB
• Volume: 290
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(96)00144-9

✦ Synopsis

The conformational behaviour of a representative azaheterocycle/thiosugar hybrid: 6-S-(benzoxazol-2-yl)-6-deoxy-l,2:3,4-di-O-isopropylidene-6-thio-a-D-galactopyranose, 1, has been characterised by X-ray crystallography, molecular modelling and NMR studies. The crystal of (C19Ha3NO6 S) belongs to the monoclinic space group P2 I, with a = 8.4330(4), b = 10.287(3), c = 11.417(4) ,~, /3 = 101.66(5) °, V = 970.0(5) ,~3, and Z = 2. The structure has been determined by X-ray diffraction at 299 K using an area detector. Least-squares refinement based on reflections yielded a final wR2 of 0.098, with R1 = 0.040 [for 2210 reflections with F o > 4o-(F o)]. The pyranose ring adopts a conformation between that of the screw-boat, °S 5, and the twist-boat, °T 2 forms. Proton NMR chemical shifts have been assigned by measurement of ID and 2D spectra. The C-5-C-6 conformer populations in CDC13 solution have been estimated. In parallel, a