Synthesis, NMR, and conformational studies of fucoidan fragments. IV. 4-mono- and 4,4'-disulfated (1 -> 3)-alpha-L-fucobioside and 4-sulfated fucoside fragments

Propyl 4-O-sulfonato- and 4,4'-di-O-sulfonato-3-O-alpha-L-fucopyranosyl-alpha-L-fucopyranosides, which are related to fragments of brown algal fucoidans, have been synthesized. Their spectral (H-1 and C-13 NMR, NOE) and conformational properties have been studied in combination with molecular modeling and compared with the respective non-sulfated propyl fucobioside. Correlations between chemical shifts and conformational properties of these compounds were investigated.