structural studies on k-凯发网

oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from kappaphycus striatum carrageenan. three oligosaccharides were purified by strong-anion exchange high-performance chromatography. their structure was elucidated using mass spectral and nmr data. negative-ion electrospray ionization (esi) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the k-carrageenan oligosaccharides. 2d nmr techniques, including 1h-1h cosy, 1h-1h tocsy and 13c-1h hmqc, were performed to determine the structure of a trisulfated pentasaccharide. 1d nmr and esims were used to determine the structures of a carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. all the oligosaccharides characterized have a 4-o-sulfo-d-galactopyranose residue at both the reducing and nonreducing ends.