Disaccharides that contain 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and d-glycero-d-talo-oct-2-ulosonic acid (Ko) substituted at the 8-position by 4-amino-4-deoxy-β-L-arabinopyranosyl (Ara4N) residues have been prepared. Coupling an N-phenyltrifluoroacetimidate-4-azido-4-deoxy-l-arabinosylglycosyl donor to acetyl-protected allyl glycosides of Kdo and Ko afforded anomeric mixtures of disaccharide products in 74 and 90 % yield, respectively, which were separated by chromatography. Further extension of an intermediate Ara4N-(1→8)-Kdo disaccharide acceptor, which capitalized on a regioselective glycosylation with a Kdo bromide donor under Helferich conditions, afforded the branched trisaccharide α-Kdo-(2→4)[β-L-Ara4N-(1→8)]-α-Kdo derivative. Deprotection of the protected di- and trisaccharide allyl glycosides was accomplished by TiCl(4)-promoted benzyl ether cleavage followed by the removal of ester groups and reduction of the azido group with thiol or Staudinger reagents, respectively. The reaction of the anomeric allyl group with 1,3-propanedithiol under radical conditions afforded the thioether-bridged spacer glycosides, which were efficiently coupled to maleimide-activated bovine serum albumin. The neoglycoconjugates serve as immunoreagents with specificity for inner core epitopes of Burkholderia and Proteus lipopolysaccharides.

Lipopolysaccharide, carbohydrates, Burkholderia, glycoconjugates, Proteus, glycosylation, glycolipids, Biomimetic synthesis

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8
8	bLArap4N	99.92	68.40	68.53	52.30	60.07
	aXKdop	176.00	100.80	34.92	67.03	66.79	72.33	67.23	70.84


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8
8	bLArap4N	4.99	3.74	4.03-4.11	3.49	3.68-3.99
	aXKdop	-	-	1.77-2.03	4.03-4.11	4.01	3.61	4.03-4.11	3.78-3.94


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8
8	bLArap4N	99.92/4.99	68.40/3.74	68.53/4.03-4.11	52.30/3.49	60.07/3.68-3.99
	aXKdop			34.92/1.77-2.03	67.03/4.03-4.11	66.79/4.01	72.33/3.61	67.23/4.03-4.11	70.84/3.78-3.94

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

N[C@H]1CO[C@H](OC[C@@H](O)[C@H]2O[C@@](O)(C(=O)O)C[C@@H](O)[C@H]2O)[C@H](O)[C@H]1O

369.323 g/mol (C₁₃H₂₃NO₁₁)

Disaccharides that contain 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and d-glycero-d-talo-oct-2-ulosonic acid (Ko) substituted at the 8-position by 4-amino-4-deoxy-β-L-arabinopyranosyl (Ara4N) residues have been prepared. Coupling an N-phenyltrifluoroacetimidate-4-azido-4-deoxy-l-arabinosylglycosyl donor to acetyl-protected allyl glycosides of Kdo and Ko afforded anomeric mixtures of disaccharide products in 74 and 90 % yield, respectively, which were separated by chromatography. Further extension of an intermediate Ara4N-(1→8)-Kdo disaccharide acceptor, which capitalized on a regioselective glycosylation with a Kdo bromide donor under Helferich conditions, afforded the branched trisaccharide α-Kdo-(2→4)[β-L-Ara4N-(1→8)]-α-Kdo derivative. Deprotection of the protected di- and trisaccharide allyl glycosides was accomplished by TiCl(4)-promoted benzyl ether cleavage followed by the removal of ester groups and reduction of the azido group with thiol or Staudinger reagents, respectively. The reaction of the anomeric allyl group with 1,3-propanedithiol under radical conditions afforded the thioether-bridged spacer glycosides, which were efficiently coupled to maleimide-activated bovine serum albumin. The neoglycoconjugates serve as immunoreagents with specificity for inner core epitopes of Burkholderia and Proteus lipopolysaccharides.

Lipopolysaccharide, carbohydrates, Burkholderia, glycoconjugates, Proteus, glycosylation, glycolipids, Biomimetic synthesis

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

N[C@H]1CO[C@H](OC[C@@H](O)[C@H]2O[C@@](O)(C(=O)O)[C@@H](O)[C@@H](O)[C@H]2O)[C@H](O)[C@H]1O

385.322 g/mol (C₁₃H₂₃NO₁₂)

Disaccharides that contain 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and d-glycero-d-talo-oct-2-ulosonic acid (Ko) substituted at the 8-position by 4-amino-4-deoxy-β-L-arabinopyranosyl (Ara4N) residues have been prepared. Coupling an N-phenyltrifluoroacetimidate-4-azido-4-deoxy-l-arabinosylglycosyl donor to acetyl-protected allyl glycosides of Kdo and Ko afforded anomeric mixtures of disaccharide products in 74 and 90 % yield, respectively, which were separated by chromatography. Further extension of an intermediate Ara4N-(1→8)-Kdo disaccharide acceptor, which capitalized on a regioselective glycosylation with a Kdo bromide donor under Helferich conditions, afforded the branched trisaccharide α-Kdo-(2→4)[β-L-Ara4N-(1→8)]-α-Kdo derivative. Deprotection of the protected di- and trisaccharide allyl glycosides was accomplished by TiCl(4)-promoted benzyl ether cleavage followed by the removal of ester groups and reduction of the azido group with thiol or Staudinger reagents, respectively. The reaction of the anomeric allyl group with 1,3-propanedithiol under radical conditions afforded the thioether-bridged spacer glycosides, which were efficiently coupled to maleimide-activated bovine serum albumin. The neoglycoconjugates serve as immunoreagents with specificity for inner core epitopes of Burkholderia and Proteus lipopolysaccharides.

Lipopolysaccharide, carbohydrates, Burkholderia, glycoconjugates, Proteus, glycosylation, glycolipids, Biomimetic synthesis

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

N[C@H]1CO[C@H](OC[C@@H](O)[C@H]2O[C@@](O)(C(=O)O)C[C@@H](O[C@]3(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O3)[C@H]2O)[C@H](O)[C@H]1O

589.5 g/mol (C₂₁H₃₅NO₁₈)