6-O-glycosylation of a lipid A-subunit analog (GLA-27) with methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-α-d-manno-2-octulopyranosyl bromide)onate (a KDO derivative)

Stereoselective synthesis of the alpha-glycoside of a KDO "C"-disaccharide

The reaction of tert-butyl (4,5,7, 8-tetra-O-acetyl-3-deoxy-alpha-D-manno-2-octulopyranosyl chloride)onate donor 7 with the 6-formylgalactopyranoside acceptor 4 in the presence of SmI(2) provided only the KDO alpha-C-disaccharide 8. The bulky tert-butyl ester in the donor was used to reverse the stereochemical outcome of C-glycosylation, stereoselectively forming the alpha-"C"-disaccharide of KDO.

Synthesis of allyl 6-O-(3-deoxy-alpha- and -beta-D-manno-oct-2- ulopyranosylonic acid)-(1----6)-2-deoxy-2-[(3R)-3-hydroxytetradecanamido]- beta-D-glucopyranoside 4-phosphate and of the copolymer of the alpha anomer with acrylamide

The title disaccharides were synthesized by mercuric cyanide-catalyzed condensation of methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-alpha-D-manno-oct-2-ulopyranosyl bromide)onate and allyl 2-[(3R)-3-acetoxy-tetradecanamido]-3-O-benzyl-2-deoxy-beta-D- glucopyranoside, followed by phosphorylation of the alcoholic function of the amino sugar. The phosphorylated anomers were separated by chromatography and deprotected by conventional methods. Polymeric material was obtained by copolymerisation, catalyzed by peroxosulphate and N,N,N',N'-tetramethylethylenediamine, of the alpha anomer with acrylamide; it contained ca. one disaccharide unit for 18 acrylamide residues.

Synthesis of alpha-Kdo-(2----4)-Kdo disaccharide derivatives and their conjugation with a protected form of GLA-60, a biologically active analog of a lipid A subunit

A variety of the protected O-[(3-deoxy-alpha-D-manno-2-octulopyranosyl)onic acid]-(2----4)-3-deoxy-D-manno-2-octulosonic acid [alpha-Kdo-2(2----4)-Kdo] derivatives have been synthesized starting from methyl [2-(trimethylsilyl)ethyl 4,5,7,8-tetra-O-acetyl-3-deoxy-alpha-D-manno-2-octulopyranosid] onate. Some of these were conjugated with a protected form of a bacterial lipid A subunit-analog (GLA-60) having beneficial immunopharmacological activity, namely benzyl 2-[(3R)-3-(benzyloxy-methoxy)tetradecanamido]-2-deoxy-4-O- (diphenoxyphosphinyl)3-O-[(3R)-3-tetradecanoyloxytetradecanoyl+ ++]-beta -D-glucopyranoside.