Expedient syntheses of neoglycoproteins using phase transfer catalysis and reductive amination as key reactions.
Starting from peracetylated chloro- or bromo-glycosyl donors of N-acetylneuraminic acid, N-acetylglucosamine, glucose and lactose, the corresponding p-formylphenyl glycosides were synthesized stereospecifically under phase transfer catalysed conditions at room temperature in yields of 38-67%. After Zemplén de-O-acetylation, the formyl groups were directly and chemoselectively coupled to the lysine residues of bovine serum albumin by reductive amination using sodium cyanoborohydride. The conjugation reactions were followed as a function of time and under a series of different molar ratios of the reactants to provide glycoconjugates of varying degree of antigenicities. Thus, carbohydrate protein conjugates were made readily available using essentially two key reactions.
Roy
R
R
Department of Chemistry, University of Ottawa, Ontario, Canada.
Tropper
F D
FD
Romanowska
A
A
Letellier
M
M
Cousineau
L
L
Meunier
S J
SJ
Boratyński
J
J
D000447:Aldehydes / Q000737:chemistry; D000586:Amination; D002240:Carbohydrate Sequence; D002384:Catalysis; D006023:Glycoproteins / Q000138:chemical synthesis*; D006027:Glycosides / Q000138:chemical synthesis; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012710:Serum Albumin, Bovine / Q000737:chemistry; D000637:Transaminases / Q000378:metabolism*
D000447:Aldehydes; D006023:Glycoproteins; D006027:Glycosides; D012710:Serum Albumin, Bovine; D000637:Transaminases