Fragments of the teichoic acid-type polysaccharide of Streptococcus pneumoniae serotype 17F, containing a D-arabinitol phosphate moiety and a spacer, were synthesized. Starting from D-lyxose or D-mannose key intermediate 1-O-allyl-2,3-di-O-benzyl-5-O-benzoyl-D-arabinitol was prepared, which was condensed with tri-O-acetyl-α-L-rhamnosyl bromide. The resulting dimer was, after removal of the allyl group, phosphorylated with either N-benzyloxycarbonyl-3-aminopropyl(2-cyanoethyl)-N,N-diethylphosphoramidite or 2-cyanoethoxy(N,N-diethylamino)chlorophosphine, the latter reagent leading to a suitable phosphitedonor. The phosphite-acceptors N-benzyloxycarbonyl-3-aminopropyl 2,3-di-O-(2-methylbenzoyl)-α-L-rhamnopyranoside and N-benzyloxycarbonyl-3-aminopropyl 2,3-di-O-benzoyl-4-O-[2,3-di-O-(2-methylbenzoyl)-α-L-rhamnopyranosyl]-6-O-(2-methylbenzoyl)-β-D-glucopyranoside were prepared by selective removal of a 4-O-dichloroacetyl group from the fully protected monomer and dimer, respectively. Condensation of the phosphite-donor with the individual acceptors led to the isolation of spacer containing trimer and tetramer fragments of the title polysaccharide. Assemble of properly protected sugar units afforded inter alia the fully protected fragment [image] which, after removal of all protecting groups, was converted into the spacer containing tetramer [image].

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
4,4,0,2	aLRhap	100.4	71.4	71.0	72.8	70.1	17.6
4,4,0	xDAra-ol	66.5	75.5	70.6	71.5	63.9
4,4	P
4	aLRhap	101.4	71.3	70.9	78.4	68.9	17.7
	bDGlcp	?	74.3	75.3	78.2	76.0	61.0


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
4,4,0,2	aLRhap	5.04	4.01	3.78	3.41	3.81	1.24
4,4,0	xDAra-ol	4.06	4.14	3.66	3.68	3.67-3.76
4,4	P
4	aLRhap	4.84	3.97	3.87	3.96	4.10	1.26
	bDGlcp	4.43	3.24	3.56	3.52	3.50	3.73-3.83


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
4,4,0,2	aLRhap	100.4/5.04	71.4/4.01	71.0/3.78	72.8/3.41	70.1/3.81	17.6/1.24
4,4,0	xDAra-ol	66.5/4.06	75.5/4.14	70.6/3.66	71.5/3.68	63.9/3.67-3.76
4,4	P
4	aLRhap	101.4/4.84	71.3/3.97	70.9/3.87	78.4/3.96	68.9/4.10	17.7/1.26
	bDGlcp	?/4.43	74.3/3.24	75.3/3.56	78.2/3.52	76.0/3.50	61.0/3.73-3.83

The spectrum also has 1 signal at unknown position (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

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

686.55 g/mol (C₂₃H₄₃O₂₁P)