80832-20-8Relevant academic research and scientific papers
Anomalous Zemplen deacylation reactions of 2-O-acyl-3-O-alkyl or -3-O-glycosyl derivatives of D-galactose and D-glucose: synthesis of O-alpha-D-mannopyranosyl-(1----4)-O-alpha-L-rhamnopyranosyl-(1----3)-D- galactose and an intermediate for the preparation of 2-O-glycosyl-3-O-(alpha-D-mannopyranosyl)-D-glucoses.
Szurmai,Liptak,Snatzke
, p. 201 - 208 (2007/10/02)
Treatment of 2-O-benzoyl (1) and 2-O-acetyl (5) derivatives of benzyl 4,6-benzylidene-3-O-(2,3,4-tri-O-acetyl-alpha-L-rhamnopyranosyl)-beta-D- galactopyranoside under Zemplen conditions (catalytic amount of sodium methoxide in methanol) gave partially deacylated disaccharides in which the 2-O-acyl groups were retained. Likewise, a similar result was obtained with the beta-L-rhamnopyranosyl analogue (3) of 1. This anomalous reaction was used in a synthesis of the title trisaccharide (17) and of methyl 4,6-O-benzylidene-3-O-(2,3:4,6-di-O-isopropylidene-alpha-D-mannopyranosy l)- alpha-D-glucopyranoside, an intermediate for the synthesis of 2-O-glycosyl-3-O-(alpha-D-mannopyranosyl)-D-glucoses.
SYNTHESIS OF 2-O-α, 3-O-α, 3-O-β, AND 4-O-α-L-RHAMNOPYRANOSYL-D-GALACTOSE
Liptak Andras,Szurmai Zoltan,Nanasi Pal
, p. 13 - 22 (2007/10/02)
Condensation of benzyl 3-O-benzoyl-4,6-O-benzylidene-, benzyl 2-O-benzoyl-4,6-O-benzylidene- (2), and benzyl 2,3,6-tri-O-benzyl-β-D-galactopyranoside, separately, with tri-O-acetyl-α-L-rhamnopyranosyl bromide gave mainly α-linked disaccharide derivatives.An appreciable proportion of the β-linked disaccharide was also abtained from 2.An anomalous deacylation reaction was found for the (1-->3)-linked disaccharide, and the partially benzoylated products were isolated and characterised.The anomeric configuration of each disaccharide was established on the basis of JC-1,H-1 values.The chemical shifts for the galactose moieties of the α and β-L-rhamnopyranosyl derivatives differed in a systematic way.
