Analysis of pyruvylated beta-carrageenan by 2D NMR spectroscopy and reductive partial hydrolysis.
A polysaccharide rich in 4',6'-O-(1-carboxyethylidene)-substituted (i.e., pyruvylated) beta-carrageenan has been prepared by solvolytic desulfation of a polysaccharide containing predominantly pyruvylated alpha-carrageenan, which was extracted from the red seaweed, Callophycus tridentifer. The 13C and 1H NMR chemical shifts of pyruvylated beta-carrageenan have been fully assigned using 2D NMR spectroscopic techniques. The 4',6'-O-(1-methoxycarbonylethylidene) group, generated during chemical methylation of the polysaccharide, has been shown to survive under the conditions of acidic hydrolysis that cleave the 3,6-anhydro-alpha-D-galactosidic bonds in permethylated samples of both pyruvylated beta- and pyruvylated alpha-carrageenans. As a result, two novel pyruvylated carrabiitol derivatives have been prepared.
Falshaw
Ruth
R
Industrial Research Ltd, P.O. Box 31-310, Lower Hutt, New Zealand. r.falshaw@irl.cri.nz
Furneaux
Richard H
RH
Wong
Herbert
H
D002351:Carrageenan / Q000032:analysis* / Q000737:chemistry; D005690:Galactose / Q000031:analogs & derivatives; D006868:Hydrolysis; D015394:Molecular Structure; D009005:Monosaccharides / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular; D019289:Pyruvic Acid / Q000737:chemistry*; D000461:Rhodophyta / Q000737:chemistry; D014993:Xylitol / Q000031:analogs & derivatives
D009005:Monosaccharides; C082983:desulfated carrageenan; D019289:Pyruvic Acid; D002351:Carrageenan; D014993:Xylitol; D005690:Galactose