Constitutional and configurational assignments by 13C n.m.r. spectroscopy of Escherichia coli capsular polysaccharides containing ribose and 3-deoxy-D-manno-2-octulosonic acid (KDO)

Abstract

The ¹³C n.m.r. heteronuclear coupling constant,³J(C-1, H-3a)ca, 5 Hz, affords for the first time in a natural product, proof of the β-anomric clonfiguration of the (3-deoxy-D-manno-2-octulopyranosyl)ono (KDO) residues in the capsular polysaccharide from Escherchia coli O6 : K13 : H1, while empirical correlations and spin–lattice relaxation times (T₁-values) support the constitutional assignments made previously on this and the related, branched polysaccharide from Escherichia coli LP 1092.