Synthesis and spectroscopic characterization of hydroxycinnamoylated methyl alpha-L-arabinofuranosyl-(1-->2)- and (1-->3)-beta-D-xylopyranosides.
A reaction sequence for the preparation of methyl 5-O-feruloyl-alpha-L- arabinofuranosyl-(1-->3)-beta-D-xylopyranoside, the companion 5-O-p-coumaroyl disaccharide, and their (1-->2) analogs has been developed. The (1-->3) hydroxycinnamoylated disaccharides are available in 11 steps from L-arabinose and methyl beta-D-xylopyranoside in 17% overall yield (based on methyl beta-D-xylopyranoside). The corresponding (1-->2) materials were prepared in 9 steps in > 37% overall yield. Complete spectral characterization provides unambiguous assignments for comparison with analogous materials isolated from plant cell-walls. Conformational aspects of the prepared materials are discussed in relation to coupling-constant information.
Helm
R F
RF
USDA-Agricultural Research Service, US Dairy Forage Research Center, Madison, WI 53706.
Ralph
J
J
D001089:Arabinose / Q000031:analogs & derivatives*; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000737:chemistry; D003373:Coumaric Acids / Q000737:chemistry*; D006027:Glycosides / Q000138:chemical synthesis*; D008031:Lignin / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010944:Plants / Q000737:chemistry; D011422:Propionates
D003373:Coumaric Acids; D006027:Glycosides; D011422:Propionates; C010807:xylosides; D008031:Lignin; C004999:ferulic acid; D001089:Arabinose; C495469:p-coumaric acid