Synthesis of the colitose determinant of Escherichiacoli O111 and 3,6-di-O-(α-D-galactopyranosyl)-α-D-glucopyranoside

Abstract

TOMMY IVERSEN and DAVID R. BUNDLE. Can. J. Chem. 60, 299 (1982). The syntheses of two branched trisaccharides, which constitute important elements of enterobacterial lipopolysaccharides are described. The common structural feature of each trisaccharide is a-D-glucopyranoside, upon which branching occurs at the 0 -3 and 0 -6 positions. Selective blocking of this hexoside at 0 -2 and 0-4 by persistent blocking groups was accomplished by benzylation of 1 ,6-anhydro-P-D-glucopyranoside (1). Acetolysis of the product 2 afforded a mixture of anomeric triacetates 3 from which the corresponding 3,6-di-0-acetyI-2,4-O-benzyl-a-~-glucopyranosyl chloride (4) was prepared. The a and P 8-methoxycarbonyloctyl glycosides 5 and 6 were obtained in the ratio -2:1, when 4 was reacted with 8-methoxycarbonyloctanol. Transesterification of the a-glycoside 5 gave the aglyconic intermediate 7 from which each trisaccharide could be obtained in a one step reaction. Thus glycosylation of 7 with tetra-0-benzyl-a-D-galactopyranosyl chloride (8) or 2,4-di-0-benzyl-3,6-dideoxy-a-Lxylo-hexopyranosyl chloride (10) gave the trisaccharides 11 and 13. In both cases removal of blocking groups was achieved in a single hydrogenolysis step. Trisaccharide 12 represents a trisaccharide sequence present in the core saccharide of Salmonella lipopolysaccharides, while the colitose containing trisaccharide 14 is an essential element of the E. coli 011 1 0-antigen.TOMMY IVERSEN et DAVID R. BUNDLE. Can. J . Chem. 60, 299 (1982).On decrit la synthese de deux trisaccharides ramifies qui constituent des elements importants des lipopolysaccharides enterobacteriens. La caracteristique structurale commune a chaque trisaccharide est I'a-D-glucopyrannoside, sur lequel s'effectue les ramification en positions 0-3 et 0-6. On a p11 proteger selectivement cet hexoside en positions 0 -2 et 0 -4 a I'aide de groupes protecteurs tres stables en benzylant I'anhydro-1,6 P-D-glucopyrannose (I). L'acelotyse du compose 2 conduit a un melange de triacetates 3 anomeres a partir duquel on a prepare le chlorure de di-0-acetyl-3,6 0-benzyl-2,4 a-D-glucopyrannosyle (4). On a obtenu les a -et P-glycosides de methoxycarbonyl-8 octyle, 5 et 6, dans un rapport de 2: 1 environ en faisant reagir le compose 4 avec le methoxycarbonyl-8 octanol. La transesterification de l'a-glycoside conduit al'intermediaire aglyconique 7 a partir duquel on peut obtenir chaque trisaccharide en une seule etape. Ainsi la glycosilation du compose 7 par le chlorure de tetra-0-benzyl a-D-galactopyrannosyle (8) ou par le chlorure de di-0-benzyl-2,4 dideoxy-3,6 a-L-xylohexopyrannosyle (10) donne les trisaccharides 11 et 13. Dans les deux cas, I'hydrolyse permet d'effectuer la deprotection en une seule etape. Le trisaccharide 12 represente une suite de trisaccharides presents dans le noyau saccharique des lipopolysaccharides du type Salmonella, tandis que le trisaccharide 14 contenant la colitose est un element essentiel de I'antigene 0 de I'E. Coli 0 1 11.[Traduit par le journal] Introduction Although antigenic determ...

Molecular recognition XII. The binding of the H human blood group determinants and congeners by a lectin of Galactiatenuiflora

“…The 3-and 4-deoxy-a-L-fucopyranosyl bromides (36 and 37) were prepared from 34 and 35, which were obtained by hydrolyses of methyl 2,4-di-0-benzyl-3,6-dideoxy- (21) and methyl 2,3-di-0-benzyl-4,6-dideoxy-a-L-xylo-hexopyrano- sides.4 ~alide-ion-catalyzed reactions of the bromides 36 and 37 with 44 then produced the 3c-and 4c-deoxy blocked trisaccharides 50 and 51 in 86 and 91% yields. Debenzoyla---'P.…”

“…The I3C nmr data are reported in Table 1. (15 mL) and dichloromethane (3 mL) was kept at room temperature for 5 h. After neutralization with Amberlite IRC 50 H + , filtration, and evaporation to dryness, the resulting powder (21) was desolved in N,N-dimethylformamide (7 mL) and acetonitrile (15 mL) and then treated with a,a-dimethoxytoluene (0.24 mL, 1.5 mmol) and p-toluenesulfonic acid (25 mg) for 1 day. The mixture was neutralized with triethylamine and evaporated to dryness.…”

Structural background for serological cross‐reactivity between bacteria of different enterobacterial serotypes

“…The presence of colitose in the O ‐antigens was proved by NMR, as well. The approval of the presence of colitose in the LPS of P. morganii O34 is of big importance, because colitose has been reported to be an immunodominant component in “cross”‐like structures , and because only a few bacterial species are able to synthesize this sugar .…”

Total Synthesis of theEscherichia coliO111O‐Specific Polysaccharide Repeating Unit

“…The 1 J C1,H1 coupling constant of 164. 8 Hz was characteristic for the formation of a b-glycosidic linkage. The coupling of nucleophile 23 with thiogalactoside 7 by activation with NIS and TfOH in Et 2 O/CH 2 Cl 2 , followed by cleavage of the levulinoyl ester, afforded target disaccharide 24 in 48 % yield over two steps.…”

“…8 Hz was characteristic for the formation of a b-glycosidic linkage. Fmoc cleavage by treatment with triethylamine afforded b-glucosamine nucleophile 23 in 71 % yield over two steps.…”