Synthesis and conformational analysis of the plant hormone (auxin) related 2-(indol-3-yl)ethyl and 2-phenylethyl β-d-xylopyranosides and their 2,3,4-tri-O-acetyl derivatives

✍ Scribed by Sanja Tomić; Bouke P. van Eijck; Biserka Kojić-Prodić; Jan Kroon; Volker Magnus; Biljana Nigović; Goran Laćan; Nebojša Ilić; Helmut Duddeck; Monika Hiegemann

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 1023 KB
• Volume: 270
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(95)00037-t

✦ Synopsis

The synthesis, structure analysis by X-ray diffraction and NMR spectroscopy (including also 1H {1H}NOE measurements), as well as molecular mechanics and dynamics of D-xylopyranose conjugates of 2-(indol-3-yl)ethanol (1) and 2-phenylethanol ( 2) are described. The per-O-acetylated derivatives of 2-(indol-3-yl)ethyl fl-o-xylopyranoside (4fl) and 2-phenyletbyl fl-D-xylopyranoside (7/3) were prepared [along with corresponding a-D-isomers (4a and 7a) and 1,2-O-orthoacetates (5,8)] by Koenigs-Knorr condensation of the aglycone alcohols with 2,3,4-tri-O-acetyl-a-Dxylopyranosyl bromide. Glycoside 4fl was deprotected to yield 2-(indol-3-yl) ethyl /3-0xylopyranoside (6). The crystal structures of 4/3 and 7/3 were determined. The crystals of both compounds are monoclinic, space group P 21 with a = 11.985(1), b = 7.317(1), c = 12.428(1) ,~, 13 = 93.2(1) °, Z = 2 (4/3); a = 5.809(1), b ---19.833(1), c = 8.912(1) A, /3 = 106.0(1) °, Z = 2 (7/3). The fl-D-xylopyranose rings are in the 4C 1 chair conformation. The results of the theoretical * Corresponding author.