Enzymatic Synthesis of Galactose-Containing Disaccharides Employing β-Galactosidase fromBacillus circulans

Directed and Efficient Syntheses of β(1→4)-Linked Galacto-Oligosaccharides

“…However, their isolation from pectic cell wall material is exceedingly cumbersome and has rarely provided well defined products Ϫ exceptions being mg quantities of galactobiose, [13] -triose, and -tetraose. [12] Similarly, the generation of oligo-β(1Ǟ4)-galactosides by β-galactosidase-induced galactosyl transfer has, despite its simplicity, not passed the β(1Ǟ4)-galactobiose stage, [32,33] while their chemical synthesis has proven to be a particularly formidable task, since the axially disposed 4-OH of a galactosyl acceptor, necessarily carrying blocking groups at O-6 and O-3, is sterically less accessible for glycosylation than primary or equatorial OHs, aside from its being comparatively unreactive to begin with.…”

Synthesis of Novel Di‐ and Trisaccharide Mimetics with Non‐Glycosidic Amino Bridges

“…Reactions with compound 15 were performed at room temperature for 3 days, while reactions with GlcNAc (14) required 3 h at 55°C. [27] Under these conditions, neither the 6-O-mesylate 3 nor the 6azido-6-deoxy 4 compounds were accepted by the enzyme. However, reaction of amine 5 with acceptor 15 could be achieved and resulted in the formation of allyl 6-amino-6deoxy-β--galactopyranosyl-(1Ǟ4)-2-acetamido-2-deoxyα--glucopyranoside (21).…”

Convenient enzymatic synthesis of a p-nitrophenyl oligosaccharide series of sialyl N-acetyllactosamine, sialyl Lex and relevant compounds

“…The structure of pNP galactosylated trisaccharide 6 was confirmed compared to the previous data. 23 (J 1,2 7.2 Hz), 4.66 (J 1 000 ,2 000 8.4 Hz), 4.62 (J 1 00 ,2 00 7.8 Hz) and 4.56 (J 1 0 ,2 0 7.8 Hz) in the 1 H NMR spectrum of tetrasaccharide 7 were shown to be all b-linkage. The 13 C NMR signals also revealed the structure 7 [d 79.3 (C-4), 79.0 (C-4 0 ) and 78.8 (C-4 00 )], which was downshifted compared to other carbons.…”