The trisaccharides allyl O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→6)-O-2-acetamido-2-deoxy-β-D-glucopyranosyl-(1→6)-2-acetamido-2-deoxy-α- and -β-D-glucopyranoside (16a and 16b), the tetrasaccharides allyl O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→4)-O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→6)-O-2-acetamido-2-deoxy-β-D-glucopyranosyl-(1→6)-2-acetamido-2-deoxy-α- and -β-D-glucopyranoside (19a and 19b), and the pentasaccharides allyl O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→8)-O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→4)-O-(sodium 3-deoxy-α-D-manno-2-octulopyranosylonate)-(2→6)-O-2-acetamido-2-deoxy-β-D-glucopyranosyl-(1→6)-2-acetamido-2-deoxy-α- and -β-D-glucopyranoside (23a and 23b) were prepared. The glycosidic linkages were formed using 1,3,4,6-tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose (6) and FeCl3 as promoter as well as per-O-acetylated Kdo mono- and di-saccharide bromide derivatives (12 and 20) under Helferich conditions. The oligosaccharides, which correspond to dephosphorylated part-structures of enterobacterial and chlamydial lipopolysaccharides, were characterized by NMR spectroscopy as well as plasma desorption and matrix-assisted laser desorption mass spectrometry.

Lipopolysaccharide, NMR, synthesis, structure, core, epitope, Chlamydia, mass spectrometry

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8
1,6,6	aXKdop	175.6	101.0	35.2	67.2	67.4	72.6	70.6	64.4
1,6,2	Ac
1,6	bDGlcpN	102.5	56.5	74.9	71.7	75.3	63.2
1,2	Ac
1	bDGlcpN	101.0	56.6	75.0	71.3	75.7	69.9
	Allyl


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8
1,6,6	aXKdop	-	-	1.84-2.12	4.11	4.06	3.69	3.98	3.70-3.97
1,6,2	Ac	-	2.06-2.08
1,6	bDGlcpN	4.56	3.77	3.56	3.47	3.60	3.62-3.68
1,2	Ac	-	2.06-2.08
1	bDGlcpN	4.57	3.72	3.55	3.38	3.61	3.70-4.23
	Allyl


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8
1,6,6	aXKdop			35.2/1.84-2.12	67.2/4.11	67.4/4.06	72.6/3.69	70.6/3.98	64.4/3.70-3.97
1,6,2	Ac	NMR TSV error 2: unequal length of 13C and 1H datasets
1,6	bDGlcpN	102.5/4.56	56.5/3.77	74.9/3.56	71.7/3.47	75.3/3.60	63.2/3.62-3.68
1,2	Ac	NMR TSV error 2: unequal length of 13C and 1H datasets
1	bDGlcpN	101.0/4.57	56.6/3.72	75.0/3.55	71.3/3.38	75.7/3.61	69.9/3.70-4.23
	Allyl

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C=CCO[C@@H]1O[C@H](CO[C@@H]2O[C@H](CO[C@]3(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O3)[C@@H](O)[C@H](O)[C@H]2NC(C)=O)[C@@H](O)[C@H](O)[C@H]1NC(C)=O

684.645 g/mol (C₂₇H₄₄N₂O₁₈)