J. Lehmann et al., SELECTIVE DEFUCOSYLATION BY MERCAPTOLYSIS - A POTENTIAL STEP IN ANALYZING BRANCHED OLIGOSACCHARIDES, Carbohydrate research, 264(2), 1994, pp. 199-207
A method of stepwise chemical degradation was elaborated on a mu g qua
ntity of 3-O-alpha-L-fucosyllactose. The key step, TiCl4-catalysed dit
hioacetal formation from the permethylated N-4-nitrophenyl triosylamin
e (4) was accompanied by quantitative defucosylation. [C-14]Acetylatio
n of the dried mercaptalation mixture gave radiolabelled -beta-D-galac
topyranosyl)-2,6-diO-methyl-D-glucose diethyl dithioacetal (7) and 5-O
-[C-14]acetyl-2,3,4-tri-O-methyl-L-fucose diethyl dithioacetal (8). Th
e former was further degraded via the bis(sulfone), and thereby 2,3,4,
6-tetra-O-methyl-D-galactose (13) was expelled. The monosaccharide bra
nches, fucose and galactose, were identified as derivatives 8 and 13,
respectively, by comparison with authentic samples. Isolation of micro
quantities of products was carried out by preparative TLC.