SYNTHESE EN SERIE D-XYLOPYRANOSE: TRI-O-ACETYL-D-XYLOSES ET DERIVES CHLOROACETYLES

Article abstract of DOI:10.1016/S0008-6215(00)80731-4

Selective acetylation of D-xylose with acetic anhydride in dry pyridine at -30 deg C gave 1,2,3- and 1,2,4-tri-O-acetyl-α-D-xylopyranose with traces of 2,3,4-tri-O-acetyl-D-xylopyranose.Acetylation of D-xylose under conditions differing from the preceding ones only with respect to an azotropic distillation of an excess of pyridine before addition of acetic anhydride afforded a mixture of the eight possible triacetates.Unambiguous synthesis of 1,2,3-, 1,2,4-, and 1,3,4-tri-O-acetyl-β-D-xylopyranose was obtained from 3,4-di-O-acetyl-1,2-O-(1-ethoxyethylidene)-α-D-xylopyranose, which also gave 1,3,4-tri-O-acetyl-α-D-xylopyranose.The aforementioned O-acetyl derivatives and the derived monochloroacetyl compounds were analyzed by ¹³C- and ¹H-n.m.r. spectroscopy at 62.86 and 250 MHz, respectively.