Studies on the stereoselective synthesis of a protected α-D-Gal-(1→2)-D-Glc fragment

A novel 1,2-cis stereoselective synthesis of protected α-D-Gal-(1→2)-D-Glc fragments was developed. Methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside (13), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside (15), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (17), and methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-β-D-glucopyranoside (19) were favorably obtained by coupling a new donor, isopropyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-1-thio-β-D-galactopyranoside (2), with acceptors, methyl 3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside (4), methyl 3,4,6-tri-O-benzoyl-α-D-glucopyranoside (5), methyl 3-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (8), and methyl 3,4,6-tri-O-benzoyl-β-D-glucopyranoside (12), respectively. By virtue of the concerted 1,2-cis α-directing action induced by the 3-O-allyl and 4,6-O-benzylidene groups in donor 2 with a C-2 acetyl group capable of neighboring-group participation, the couplings were achieved with a high degree of α selectivity. In particular, higher α/β stereoselective galactosylation (5.0:1.0) was noted in the case of the coupling of donor 2 with acceptor 12 having a β-CH(3) at C-1 and benzoyl groups at C-4 and C-6.     

Solution and solid-state structure of N-acetamido-3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosylamine

High resolution 1H NMR and 13C NMR spectroscopic and single crystal X-ray structural analyses of N-acetamido-3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosylamine (1), a minor product of azidonitration reaction of 3,4,6-tri-O-acetyl galactal, are reported. The solution phase studies of 1 reflect that the compound exists in 4C1 conformation with cis-orientation of the substituents at C-1 and C-2. The solid-state structure of 1 reveals that a molecule of water is entrapped in the solid state of 1 and this water molecule serves to mediate N-H...O and C-H...O interactions.     

Construction of a branched chain at C-3 of a hexopyranoside. Synthesis of miharamycin sugar moiety analogs

Synthesis of the conveniently protected epimer at C-3' of the miharamycin sugar moiety was accomplished starting from the corresponding 3,3'-spiroepoxide. Reaction of the epoxide with lithium cyanide, followed by hydrolysis and spontaneous cyclization, afforded the intermediate deoxylactone methyl 4,6-O-benzylidene-3-C-(carboxymethyl)-alpha-D-glucopyranoside-3',2-lacto ne (8). Stereoselective hydroxylation with MoO5 x py x HMPA, reduction with lithium aluminum hydride and cyclization with diethyl azodicarboxylate-triphenylphosphine gave the target molecule methyl 2,3'-anhydro-4,6-O-benzylidene-3-C-[(R)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside (5). Direct reduction of 8 gave other analogs having no C-3' hydroxyl group together with having a C-3' hydroxyl group (hemiacetal). In addition, C-3' epimers were also synthesized through C-3', C-3' dihydroxy analogs. Wittig reaction of an appropriate ketosugar with [(ethoxycarbonyl)methylene]triphenylphosphorane leading to a 7:3 Z/E mixture, followed by hydroxylation with osmium tetroxide, reduction and cyclization afforded the target molecule 5 and the miharamycin sugar moiety methyl 2,3'-anhydro-4,6-O-benzylidene-3-C-[(S)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside. Examination of X-ray data for 5 and its NMR spectroscopy data allowed us to explain a contradiction reported in the literature.     

Synthesis of a sialyl-alpha-(2-->6)-lactosamine trisaccharide with a 5-amino-3-oxapentyl spacer group at C-1I.

As part of a continuing study aimed to achieve improved monoclonal antibodies against carcinoembryonic antigen (CEA) carbohydrate fragments, the synthesis of a sialyl-(2-->6)-lactosamine trisaccharide with a 5-amino-3-oxapentyl spacer group at C-1I has been developed. Two different routes to access this target are described. For this purpose 5-azido-3-oxapentyl 6-O-benzyl-2-deoxy-2-phthalimido-beta-D-glucopyranoside (4) was selectively beta-galactosylated in 81% yield using the crystalline 2,3-di-O-acetyl-4,6-O-benzylidene-alpha-D-galactopyranosyl trichloroacetimidate as the donor, taking advantage of the bulky phthalimido group at C-2 of 4. On the other hand, galactosylation of the suitable protected acceptor 5-azido-3-oxapentyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside with the crystalline 2,3-di-O-acetyl-4,6-O-benzylidene-alpha-D-galactosyl bromide renders the corresponding disaccharide in a moderate 58% yield. Despite the fact that the first strategy, unlike the second one, requires a hydrazinolysis-acetylation reaction at the disaccharide stage, it was found to be more convenient to access the disaccharide acceptor. Sialylation was performed using a thiophenyl donor under an NIS-TfOH activation procedure in acetonitrile to give a mixture of alpha and beta trisaccharides in 49 and 16% yields, respectively.     

Studies on the stereoselective synthesis of a protected α-d-Gal-(1→2)-d-Glc fragment

A novel 1,2-cis stereoselective synthesis of protected α-d-Gal-(1→2)-d-Glc fragments was developed. Methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-d-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-α-d-glucopyranoside (13), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-d-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-d-glucopyranoside (15), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-d-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranoside (17), and methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-d-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-β-d-glucopyranoside (19) were favorably obtained by coupling a new donor, isopropyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-1-thio-β-d-galactopyranoside (2), with acceptors, methyl 3-O-benzoyl-4,6-O-benzylidene-α-d-glucopyranoside (4), methyl 3,4,6-tri-O-benzoyl-α-d-glucopyranoside (5), methyl 3-O-benzoyl-4,6-O-benzylidene-β-d-glucopyranoside (8), and methyl 3,4,6-tri-O-benzoyl-β-d-glucopyranoside (12), respectively. By virtue of the concerted 1,2-cis α-directing action induced by the 3-O-allyl and 4,6-O-benzylidene groups in donor 2 with a C-2 acetyl group capable of neighboring-group participation, the couplings were achieved with a high degree of α selectivity. In particular, higher α/β stereoselective galactosylation (5.0:1.0) was noted in the case of the coupling of donor 2 with acceptor 12 having a β-CH₃ at C-1 and benzoyl groups at C-4 and C-6.     

Circular dichroism of 1,3-dioxane-type (2'-naphthyl)methylene acetals of glycosides

The CD spectra are reported for a series of 1,3-dioxane-type 4,6-O-(2'-naphthyl)methylene acetals of carbohydrates with and without interacting aromatic protective groups on the C-1, C-2, and C-3 hydroxy groups. In the absence of interacting chromophores, the signs of the (1)B transitions are not sensitive to the configuration of C-4, while the signs of the weak (1)L(a) bands are opposite in the galacto and gluco derivatives. The equatorial parallel conformation is found to be the preferred conformation of the 2-naphthyl group in the solid state by X-ray diffraction. The intense (1)B(a) and (1)B(b) transitions of the naphthalene chromophore allowed a safe configurational assignment by exciton coupled interaction with the aromatic protective groups in para-methoxyphenyl-beta-D-glycosides. The origin of the observed CEs were deduced and the additivity of the interactions was studied. The direction of the hydrogenolytic cleavage of 4,6-O-(2'-naphthyl)methylene acetal of carbohydrates could also be detected by the (1)B(b) transition of the 2-naphthyl chromophore.     

Stereoselective synthesis of methyl 4,6-O-benzylidene-2-C-methoxycarbonylmethyl-alpha-D-ribo-hexopyranosid-3-ulose, and its X-ray crystallographic analysis

Methyl 4,6-O-benzylidene-2-C-methoxycarbonylmethyl-alpha-D-ribo-hexopyranosid-3-ulose has been stereoselectively synthesized in 65% yield by reaction of methyl 4,6-O-benzylidene-alpha-D-arabino-hexopyranosid-2-ulose with diethyl malonate. X-ray crystallographic structure analysis reveals that the chain-branch and the OH group are bonded to C-2 in axial and equatorial positions, respectively. The molecules in the crystal lattice are stacked along a one-dimensional chain, with intermolecular hydrogen bonds between O-8 of one molecule and 2-OH of the next as well as intramolecular hydrogen bonds between O-3 and 2-OH. All phenyl groups are parallel as well as the planes of sugar rings in the molecular columnar stacking.     

Simultaneous regioselective protection of phenyl 1-thioglucosides at the C-3 and C-6 or at the C-2 and C-6 hydroxy groups

Simultaneous regioselective 3,6- or 2,6-selective protection of 1-thio-beta- or alpha-D-glucopyranosides is described. The C-3 and C-6 hydroxy groups of the beta-thioglucoside were selectively protected with triisopropylsilyl or tert-butyldiphenylsilyl trifluoromethanesulfonate. The C-2 and C-6 hydroxy groups of the alpha-thioglucoside were selectively protected with tert-butyldiphenylsilyl trifluoromethanesulfonate.     

2-O-Methyl- and 3,6-Di-O-methyl-cellulose from Natural Cellulose: Synthesis and Structure Characterization

For the first time, 2-O-methyl- (2MC) and 3,6-di-O-methyl-cellulose (36MC) were synthesized via 3-O-allyl- and 3-O-methyl-cellulose, respectively. Position 6 of 3-O-allyl- and 3-O-methyl-cellulose was protected with the 4-methoxytrityl groups. The reaction time and temperature were optimized to achieve a high regioselectivity at C-6 and to prevent the introduction of the 4-methoxytrityl group at C-2 of the polymer. It was found that the substituent at C-3 of 3-O-functionalized celluloses influenced the reactivity of the hydroxyl group at C-6. The structure was characterized by means of (1)H and (13)C NMR spectroscopy of the acetates of 2MC and 36MC. 2MC and 36MC were soluble in water and did not show thermoreversible gelation.     

Highly efficient preparation of tumor antigen-containing glycopeptide building blocks from novel pentenyl glycosides

O-Glycosylated amino acids containing the tumor-associated T(Tf)-antigen (beta-D-Gal-(1-->3)-alpha-D-GalNAc) disaccharide unit were conveniently synthesized in seven steps starting from D-galactose via an n-pentenyl glycoside (NPG) building block. Azidonitration of 3,4,6-tri-O-acetyl-D-galactal, followed by nitrate displacement with simultaneous acetate hydrolysis with sodium 4-penten-1-oxide, afforded n-pentenyl 2-deoxy-2-azidogalactoside (3) in near quantitative yield. Subsequent high-yielding transformations resulted in the synthesis of the key glycosyl donor n-pentenyl beta-disaccharide 5 that was employed for the stereospecific preparation of glycosyl amino acids via NIS-promoted glycosylations with serine or threonine acceptors. The surprising utility of the reaction of sodium 4-penten-1-oxide with anomeric nitrates encouraged the detailed exploration of the action of a variety of nucleophiles on anomeric nitrates for the synthesis of useful 2-azido glycosyl donors directly from the 'classic' Lemieux azidonitration product of protected galactals. This expedient synthesis (28% overall yield from 1 to 7a) that makes use of heretofore rarely exploited pentenyl 2'-azidoglycosides, should be a valuable entry in the armamentarium of routes to biologically relevant glycopeptides in both mono- and multivalent forms.     

Synthesis and biological activity of anomeric muramoyldipeptide butylglycosides

The synthesis of anomeric butyl glycosides of muramyl dipeptide was reported. alpha-Butyl glycoside of N-acetyl-D-glucosamine was 4,6-O-benzylidenated and the benzylidene derivative was 3-O-alkylated by the Williamson reaction with sodium (S)-2-chloropropionate. The resulting protected alpha-butyl glycoside of muramic acid was then condensed with L-Ala-D-iGln-OBzl by the DCC-HOSu method. Mild acidic hydrolysis and subsequent catalytic hydrogenolysis of the resulting glycopeptide yielded the target alpha-butyl glycoside of N-acetyl-L-alanyl-D-isoglutamine. In the synthesis of beta-butyl glycoside of N-acetylmuramyl-L-alanyl-D-isoglutamine, 2-acetamido- 4,6-di-O-acetyl-2-deoxy-3-O-[(R)-1-(methoxycarbonyl)ethyl]-alpha- D-glucopyranose, a 1-OH derivative of muramic acid, was the key compound. Its interaction with the excess thionyl chloride resulted in the corresponding glycosyl halide, which was condensed with n-butanol according to Helferich. O-Deacetylation, 4,6-isopropylidenation, and subsequent alkaline hydrolysis of the resulting compound gave the protected beta-butyl glycoside of muramic acid. Its activation and condensation with L-Ala-D-iGln-OBzl and the subsequent removal of protective groups were performed in the same manner as the reactions in the synthesis of alpha-butyl glycoside of N-acetyl-L-alanyl-D-isoglutamine. The adjuvant activity of the butyl glycosides to HIV proteins rgp160 and rgp120 and their ability to affect in vitro HIV replication and the proliferation of mouse spleen T-cells were examined. The biological activity of anomeric muramyl dipeptides was shown to depend essentially on the configuration of their anomeric center.     

A first total synthesis of a novel sulfated ganglioside, 3'-O-sulfo-GM1b

A first total synthesis of a novel sulfated ganglioside, 3'-O-sulfo-GM1b, is described. The suitably protected gangliotriose (GgOSe3) derivative, 2-(trimethylsilyl)ethyl (2-acetamido-4,6-O-benzylidene-2-deoxy-beta-D-galactopyranosyl)-(1-->4)-(2,6-di-O-benzyl-3-O-p-methoxybenzyl-beta-D-galactopyranosyl)-(1-->4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside was glycosylated with the alpha-NeuAc-(2-->3)-galactose donor to give the protected GM1b oligosaccharide (95%). After proper manipulation of the protecting groups, the oligosaccharide was converted into the target ganglioside by the successive introduction of the ceramide and sulfo groups, followed by complete deprotection.     

Mode of action on deacetylation of acetylated methyl glycoside by cellulose acetate esterase from Neisseria sicca SB

The regioselective deacetylation of purified cellulose acetate esterase from Neisseria sicca SB was investigated on methyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside and 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranoside. The substrates were used as model compounds of cellulose acetate in order to estimate the mechanism for deacetylation of cellulose acetate by the enzyme. The enzyme rapidly deacetylated at position C-3 of methyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside to accumulate 2,4,6-triacetate as the main initial reaction product in about 70% yield. Deacetylation was followed at position C-2, and generated 4,6-diacetate in 50% yield. The enzyme deacetylated the product at positions C-4 and C-6 at slower rates, and generated 4- and 6-monoacetates at a later reaction stage. Finally, it gave a completely deacetylated product. For 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranoside, CA esterase deacetylated at positions C-3 and C-6 to give 2,4,6- and 2,3,4-triacetate. Deacetylation proceeded sequentially at positions C-3 and C-6 to accumulate 2,4-diacetate in 55% yield. The enzyme exhibited regioselectivity for the deacetylation of the acetylglycoside.     

Synthesis of beta-D-GlcA-(1----3)-beta-D-Gal disaccharides with 4- and 6-sulfate groups and 4,6-disulfate groups.

The sodium salts of the 6-sulfate 7, the 4-sulfate 10, and the 4,6-disulfate 12 of benzyl 3-O-(beta-D-glucopyranosyl uronate)-beta-D-galactopyranoside (5) have been synthesized. Methyl (2,3,4-tri-O-acetyl-1-bromo-1-deoxy-alpha-d-glucopyran)uronate (1) was coupled with benzyl 2-O-benzoyl-4,6-O-benzylidene-beta-D-galactopyranoside (2) to yield 3. The benzylidene acetal of 3 was hydrolyzed to give benzyl 2-O-benzoyl-3-O-[methyl (2,3,4-tri-O-acetyl-beta-D-glucopyranosyl)uronate]-beta-D-galactopyra noside (4). Compound 4 was utilized as a key intermediate to prepare the sulfated disaccharides 7,10, and 12. Direct sulfation of 4 with sulfur trioxide-trimethylamine for 2 days yielded the 6-sulfate 6. The 4,6-disulfate 11 was accessible by running the reaction under the same conditions for 14 days. The 4-sulfate 9 was obtained after protecting the 6-OH group of 4 by reaction with benzoyl imidazole to give the 6-benzoate 8, followed by sulfation under vigorous conditions. Treatment of the protected compounds 4, 6, 9, and 11 with aqueous sodium hydroxide in tetrahydrofuran gave the unprotected 5, 7, 10, and 12, respectively.     

Structure-activity relationships of progesterone derivatives that bind to the digitalis receptor: modifications in A and B rings

A number of progesterone derivatives, having a 17 alpha-acetoxy group and various functions at C-3 and C-6, interact at the cardiac glycoside (CG) binding site, using [3H]ouabain in a radioligand binding assay (RBA) with membranes from dog myocardium. We now report on results of structure-activity studies concerned with modification of the A and B rings as they influence potency in the RBA. Some progesterone derivatives with 5 alpha- or 5 beta-stereochemistry show weak receptor competing activity. Among the congeners highest potency is associated with the presence of C-4 or C-4,6 unsaturation and a C-6 substituent (CH3, Cl, Br) whose importance appears to reside in its steric rather than electronic character. The C-3 function may be carbonyl, 3 beta-hydroxy or 3 beta-acetoxy when associated with C-4 or C-4,6 unsaturation. In compounds with other substituents that promote activity, C-6 alpha substitution with -CH3, -Cl, or -Br strongly enhances activity; -F, -OCH3, carbonyl, or the unsubstituted compound promotes weak binding; and -OC2H5, -OAc, -OCOOCH3, or -OH eliminates binding activity. Receptor interaction with the double bond at C-4, but not C-5, appears to be particularly important for binding. The most potent analog identified thus far is chlormadinone acetate (17 alpha-acetoxy-6-chloropregna-4,6-diene-3,20-dione), which has 1/20 the potency of ouabain in the RBA. Studies to determine optimal structural requirements for CG-receptor binding by these hormonal steroid congeners, in conjunction with appropriate biological assays, may provide insight into the nature of a putative endogenous counterpart, lead to a better understanding of the mode of action of the CG and yield CG-like compounds with superior therapeutic properties.     

The structure of the agaran sulfate from Acanthophora spicifera (Rhodomelaceae, Ceramiales) and its antiviral activity. Relation between structure and antiviral activity in agarans

The sulfated agaran isolated by water extraction from the red seaweed, Acanthophora spicifera (Rhodomelaceae, Ceramiales), is made up of A-units highly substituted with sulfate groups on C-2 (28-30%), sulfates on C-2 and 4,6-O-(1'-carboxyethylidene) groups (9-15%), and only the C-2 sulfate groups (5-8%) with small amounts of C-6 sulfate, 6-O-methyl, and nonsubstituted residues. B-units are formed mainly by 3,6-anhydro-alpha-L-galactose (15-16%) and its precursor, alpha-L-galactose 6-sulfate (10-17%), together with lesser amounts of 3,6-anhydro-alpha-L-galactose 2-sulfate, alpha-L-galactose 2,6-disulfate, alpha-L-galactose 2,3,6-tri-sulfate, alpha-L-galactose 2,6-disulfate 3-xylose, 2-O-methyl-alpha-L-galactose, and unsubstituted alpha-L-galactose. Small, but significant quantities of beta-D-xylose were found in all the fractions, together with small amounts to traces of D-glucose. Some of the fractions have high antiviral activity. Attempts to correlate structure and antiviral activity in agarans are presented.     

Syntheses of estetrol monoglucuronides.

Four possible monoglucuronides of estetrol (estra-1,3,5(10)-triene-3,15 alpha, 16 alpha, 17 beta-tetraol) have been prepared from appropriately protected estetrol by the Koenigs-Knorr reaction employing cadmium carbonate as a catalyst. Condensation of methyl acetobromoglucuronate with estetrol 15,16,17-triacetate provided the 3-glucuronide acetate-methyl ester in a satisfactory yield. Introduction of the glucuronyl residue into C-17 was similarly attained by the use of estetrol 3-benzoate 15,16-acetonide. When estetrol 3,17-diacetate and acetobromosugar were stirred in anhydrous toluene in the presence of cadmium salt, the reaction occurred at C-16 and C-15 yielding two isomeric monoglucuronide derivatives in a ratio of ca. 5 to 2. Removal of the protecting groups in the four glucuronide acetate-methyl esters gave the desired estetrol glucuronides, respectively. These synthetic substrates underwent readily enzymatic hydrolysis with beef-liver beta-glucuronidase to afford estetrol.     

Synthesis of oligosaccharides with group specificity for blood types A, B and H (Type 3)

Chemical synthesis of A, B, and H (type 3) human blood group determinant oligosaccharides (as R-glycosides, R = OCH2CH2CH2NHCOCF3) and their polymeric derivatives are reported. 4,6; 4',6'-Di-O-benzylidene derivative of Gal beta 1----3GalNAc alpha 1----R was chloroacetylated selectively at 3'-OH, the chloroacetate was alpha-fucosylated and dechloroacetylated to give protected H (type 3) trisaccharide bearing free 3'-OH. alpha-Glycosylation of the trisaccharide with 2-azido-3,4,6-tri-O-benzyl-beta-D-galactopyranosyl chloride and 2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl bromide gave rise to protected A and B tetrasaccharides, respectively. Deprotected R-glycosides were converted to OCH2CH2CH2NH2 derivatives. Their reaction with poly(4-nitrophenylacrylate) affords polyacrylamide-coupled conjugates with A, B, and H (type 3) specificity.     

Synthesis of n-octyl 2,6-dideoxy-alpha-L-lyxo-hexopyranosyl-(1-->2)-3-amino-3-deoxy-beta-D-galactopyranoside, an analog of the H-disaccharide antigen

The synthesis of an analog of the H-disaccharide antigen (2), in which the galactopyranosyl moiety bears an amino group at C-3 and the fucopyranosyl residue is deoxygenated at C-2, is reported. The key reaction in the preparation of 2 was the glycosylation of an appropriately protected n-octyl 3-azido-3-deoxy-galactopyranoside derivative with a 2,6-dideoxy thioglycoside promoted by 1-(phenylsulfinyl)piperidine and triflic anhydride. Disaccharide 2 is of interest in studies directed towards understanding the molecular basis of substrate recognition by the blood group A and B glycosyltransferases.     

Biotin sulfone tagged oligomannosides as immunogens for eliciting antibodies against specific mannan epitopes

Biotinylated tri and tetrasaccharide: α Man (1→3) α Man (1→2) α Man; α Man (1→3) α Man (1→2) α Man (1→2) α Man were prepared using methyl tertbutyl phenyl thioglycosides glycosyl donors (MBP) and biotin sulfone strategy. Three key mannosyl thioglycosidic donors have been prepared: one for 1→2 linkage and two for the 1→3 linkage (protected with a 4,6-O-benzylidene or a 4,6-di-O-benzyl). The benzyliden protected one was not found reactive enough, and the benzylated donor was preferred. These biotinylated oligomanosides were evaluated as antigen in Crohn disease diagnosis and used coupled to streptavidin as hapten for eliciting polyclonal antibodies in mice.