Jens Peter Lorentzen

Hans Paulsen; Jens Peter Lorentzen; Wolfram Kutschker

Abstract The azidonitration of 3,4,6-tri- O -acetyl-1,5-anhydro-2-deoxy- d - arabino -hex-1-enitol at low temperature afforded preponderantly the azidonitrate having the d - manno configuration. After reaction with sodium acetate, 1,3,4,6-tetra- O -acetyl-2-azido-2-deoxy-α- d -mannopyranose was directly isolated and deblocking gave 2-azido-2-deoxy- d -mannopyranose. 3,4,6-Tri- O -acetyl-2-azido-2-deoxy-α- d -mannopyranosyl bromide and 2-azido-3,4,6-tri- O -benzyl-α- d -mannopyranosyl bromide were prepared and are suitable for selective α- and β-glycoside synthesis. In the presence of platinum-oxygen, the catalytic oxidation of benzyl 2-azido-2-deoxy-α- d -mannopyranoside gave in high yields (benzyl 2-azido-2-deoxy-α- d -mannopyranosid)uronic acid from which 2-amino-2-deoxy- d -mannopyranuronic acid was obtained. By catalytic oxidation, selectively blocked derivatives of 2-amino-2-deoxy- d -mannopyranose were converted into the corresponding uronic acid derivatives.

Hans Paulsen; Jens Peter Lorentzen

Abstract In the presence of silver silicate, the reaction of 3,4,6-tri- O -acetyl-2-azido-2-deoxy-α- d -acetyl-2-azido-2-deoxy-α- d -mannopyranosyl bromide with 1,6-anhydro-2-azido-3- O -benzyl-2-deoxy-β- d -glucopyranose gave β-glycosidically linked 1,6-anhydro-2-azido-3- O -benzyl-2-deoxy-4- O -(3,4,6- O -(3,4,6-tri- O -acetyl-2-azido-2-deoxy-β- d - mannopyranosyl)-β- d d- glucopyranose. After deacetylation and catalytic oxidation with oxygen and platinum, 1,6-anhydro-2-azido-4- O -[(3-azido-2-deoxy-β- d -mannopyranosyl)uronic acid]-3- O -benzyl-2-deoxy-β- d -glucopyranose was obtained. A series of intermediate steps led to the glycosyl donor 6- O -acetyl-2-azido-3- O -benzyl-4- O -[benzyl (3,4-di- O -acetyl-2-azido-2-deoxy-β- d -mannopyranosyl)uronate]-2-deoxy-α,β-glucopyranosyl chloride which was coupled with 8-methoxycarbonyloctyl 4-azido-2- O -benzyl-4,6-dideoxy-α- d -galactopyranoside to give 8-methoxycarbonyloctyl O -[benzyl (3,4-di- O -acetyl-2-azido-2-deoxy-β- d -mannopyranosyl)uronate]-(1→4)- O (6- O -acetyl-2-azido-3- O -benzyl-2-deoxy-α- d -glucopyranosyl)-(1→3)-4-azido-2- O -benzyl-4,6-dideoxy-α- d -s galactopyranoside. Deblocking gave the spacer-linked repeating unit of the enterobacterial common antigen, β- d -Man p NAcA-(1→4)-α- d -Glc p NAc-(1→3)-α- d -Fuc p 4NAcO(CH 2 ) 8 CO 2 CH 3 .

Hans Paulsen; Jens Peter Lorentzen

Abstract The following oligosaccharide sequences containing the repeating unit of the O-specific chain of lipopolysaccharides from aeromonas salmonicida have been synthesized: α-D-Glcp-(1→3)-α-L-Rhap-(1 →3)-β-D-ManpNAcO(CH 2 ) 8 CO 2 Me, α-D-Glcp-(1 →4)-α-D-Glcp-(1→3)-α-L-Rhap-(1→3)-β-D-ManpNAcO(CH 2 ) 8 CO 2 Me and α-D-Glcp(1→4)-α-D-Glcp-(1→3)-[β-D-ManpNAc(1→4)]-L-Rha.

Hans Paulsen; Jens Peter Lorentzen

Abstract 8-Methoxycarbonyloctyl 2-azido-4,6- O -benzylidene-2-deoxy-β- d -mannopyranoside reacted with 2,3,4-tri- O -acetyl-α- l -rhamnopyranosyl bromide to give a disaccharide from the which the glycosyl-acceptor 8-methoxycarbonyloctyl 2-azido-4,6- O -benzylidene-2-deoxy-3- O -(2,4,-di- O -acetyl-α- l -rhamnopyranosyl)-β- d -manno pyranoside ( 19 ) was obtained. This glycosyl-acceptor with 2,3,4,6-tetra- O -benzyl-α- d -glucopyranosyl chloride to give trisaccharide derivative 22 and with 2,3,6-tri- O -(α- 2 H 2 )benzyl-4- O -(2,3,4,6-tetra- O -(α- 2 H 2 )benzyl-α- d -glucopyranosyl)-α- d -glucopyranosyl chloride to give tetrasaccharide derivative 29 . Deblocking of 22 yielded 8-methoxycarbonyloctyl O -(α- d -glucopyranosyl)-(1→3)- O -α- l -rhamnopyranosyl-(1→3)-2-acetamido-2-deoxy-β- d -mannopyranoside and deblocking of 29 8-methoxycarbonyloctyle O -α- d -glucopyranosyl-(1→4)- O -α- d -glucopyranosyl-(1→3)- O -α- l -rhamnopyranosyl- (1→3)-2-acetamido-2-deoxy-β- d -mannopyranoside. Both oligosaccharides represent the “repeating unit” of the O-specific chain of the lipopolysaccharide from Aeromonas salmonicida .

Hans Paulsen; Bernd Helpap; Jens Peter Lorentzen

Hans Paulsen; Jens Peter Lorentzen

Hans Paulsen; Meike Pries; Jens Peter Lorentzen

Hans Paulsen; Jens Peter Lorentzen

Bernd Baasner; Jens Peter Lorentzen

Jens Peter Lorentzen; Barbara Helpap; Oswald Lockhoff