Title Trisaccharide Research Articles

Chemical modification of lactose. XVII. Syntheses of O-.ALPHA.- and O-.BETA.-L-fucopyranosyl-(1.RAR.4)- or -(1.RAR.6)-O-.BETA.-D-galactopyranosyl-(1.RAR.4)-D-glucopyranoses (4'- or 6'-O-.ALPHA.- and -O-.BETA.-L-fucopyranosyllactoses).

1, 6-Anhydro-2, 2', 3, 3', 6'- and -2, 2', 3, 3', 4'-penta-O-benzyl-β-lactoses (4 and 7) were synthesized from 1, 6-anhydro-2, 2', 3, 3'-tetra-O-benzyl-4', 6'-O-benzylidene-β-lactose (1). Condensation of 4 with 2, 3, 4-tri-O-acetyl-α-L-fucopyranosyl bromide (acetobromofucose) in the conventional Koenigs-Knorr reaction, followed by deacetylation, gave 4'-O-linked trisaccharide derivatives bearing α- and β-L-fucopyranosyl linkages (10 and 15) in 13.4 and 25.6% yields, respectively. Analogous condensation of 7 with acetobromofucose gave a 6'-O-linked, fully protected trisaccharide bearing a β-L-fucopyranosyl linkage (20) in 64% yield. Halide ion-catalyzed condensation of 7 with 2, 3, 4-tri-O-benzyl-α-L-fucopyranosyl bromide gave a trisaccharide derivative bearing an α-L-fucopyranosyl linkage (26) in 51.8% yield. Removal of the protecting groups of 10, 15, 20, and 26 provided the title trisaccharides (14, 19, 25, and 30). 1H- and 13C-NMR spectral data of 14, 19, 25, 30, and synthetic intermediates are also presented.

Synthesis ofO-α-L-Fucopyranosyl-(1→2)-O-β-D-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-D-glucopyranose. The H-Blood Group Specific Trisaccharide

Abstract Different reaction conditions were investigated for the preparation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside (5). Compound 5 on reaction with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide afforded the 4-O-substituted 2-acetamido-2-deoxy-β-D-glucopyranosyl derivative which, on O-deacetylation, gave benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-β-D-galactopyranosyl-β-D-glucopyranoside (8). The trimethylsilyl (Me3Si) derivative of 8, on treatment with pyridineacetic anhydride-acetic acid for 2 days, gave the disaccharide derivative having an O-acetyl group selectively introduced at the primary position and Me3Si groups at the secondary positions. The latter groups were readily cleaved by treatment with aqueous acetic acid in methanol to afford benzyl 2-acetamido-4-O-(6-O-acetyl-β-D-galactopyranosyl)-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside, which on isopropylidenation gave the desired, key intermediate benzyl 2-acetamido-4-O-(6-O-acetyl-3,4-O-isopropylidene-β-D-galactopyranosyl)-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside (12). Reaction of 12 with 2,3,4-tri-O-benzyl-α-L-fucopyranosyl bromide under catalysis by bromide ion afforded the trisaccharlde derivative from which the title trisaccharide was obtained by systematic removal of the protective groups. The structures of the final trisaccharide and of various intermediates were established by 1H and 13C NMR spectroscopy.

Carbohydrate components of flavonol triaosides: A convenient synthesis of O-α- l-rhamnopyranosyl-(1→3)- O-α- l-rhamnopyranosyl-(1→6)- d-Galactose and O-α- l-rhamnopyranosyl-(1→2)- O-α- l-rhamnopyranosyl-(1→6)- d-galactose

Condensation of 1,2:3,4-di- O-isopropylidene-α- d-galactopyranose ( 1) with 2,4-di- O-acetyl-3- O-(2,3,4-tri- O-acetyl-α- l-rhamnopyranosyl)-α- l-rhamnopyranosyl bromide ( 2), followed by subsequent removal of the isopropylidene and acetyl groups from the product, afforded the first of the title trisaccharides. The reaction of 1 with 3,4-di- O-benzyl-2- O-p-nitrobenzoyl-α- l-rhamnopyranosyl bromide and deacylation of the product gave a disaccharide derivative that was treated with 2,3,4-tri- O-acetyl-α- l-rhamnopyranosyl bromide. Removal of the protecting groups from the product gave the second ( 15) of the title trisaccharides. The reaction of 1 with the acetobromo derivative of 2- O-α- l-rhamnopyranosyl- l-rhamnose, with subsequent removal of protecting groups from the product, also gave trisaccharide 15.

Synthesis, and carbon-13 n.m.r. study, of O-α- l-rhamnopyranosyl-(1→3)- O-α- l-rhamnopyranosyl-(1→2)- l-rhamnopyranose and O-α- l-rhamnopyranosyl-(1→3)- O-α- l-rhamnopyranosyl (1→3)- l-rhamnopyranose, constituents of bacterial, cell-wall polysaccharides

O-α- l-Rhamnopyranosyl-(1→3)- l-rhamnopyranose ( 19) and O-α- l-rhamnopyranosyl-(1→2)- l-rhamnopyranose were obtained by reaction of benzyl 2,4- ( 7) and 3,4-di- O-benzyl-α- l-rhamnopyranoside ( 8) with 2,3,4-tri- O-acetyl-α- l-rhamnopyranosyl bromide, followed by deprotection. The per- O-acetyl α-bromide ( 18) of 19 yielded, by reaction with 8 and 7, the protected derivatives of the title trisaccharides ( 25 and 23, respectively), from which 25 and 23 were obtained by Zemplén deacetylation and catalytic hydrogenolysis, With benzyl 2,3,4-tri- O-benzyl-β- d-galactopyranoside, compound 18 gave an ≈3:2 mixture of benzyl 2,3,4-tri- O-benzyl-6- O-[2,4-di- O-acetyl-3- O-(2,3,4-tri- O-acetyl-α- l-rhamnopyranosyl)-α- l-rhamnopyranosyl]-β- d-galactopyranoside and 4- O-acetyl-3- O-(2,3,4-tri- O-acetyl-α- l-rhamnopyranosyl)-β- l-rhamnopyranose 1,2-(1,2,3,4-tetra- O-benzyl-β- d-galactopyranose-6-yl (orthoacetate). The downfield shift at the α-carbon atom induced by α- l-rhamnopyranosylation at HO-2 or -3 of a free α- l-rhamnopyranose is 7.4-8.2 p.p.m., ≈1 p.p.m. higher than when the (reducing-end) rhamnose residue is benzyl-protected (6.6-6.9 p.p.m.). α- l-Rhamnopyranosylation of HO-6 of gb- d-galactopyranose deshields the C-6 atom by 5.7 p.p.m. The 1 2-orthoester ring structure [O 2,C(me)OR] gives characteristic resonances at 24.5 ±0.2 p.p.m. for the methyl, and at 124.0 ±0.5 p.p.m. for the quaternary, carbon atom.

Synthesis of blood-group substances. Part 11. Synthesis of the trisaccharide O-α-D-galactopyranosyl-(1 → 3)-O-β-D-galactopyranosyl-(1 → 4)-2-acetamido-2-deoxy-D-glucopyranose

Reaction of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide with benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside in 1,2-dichloroethane in the presence of mercuric bromide and molecular sieves (4 A) provided after O-deacetylation crystalline benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(β-D-galacto pyranosyl)-α-D-glucopyranoside. Acetonation followed by benzylation and mild acid hydrolysis provided crystaline benzyl 2-acetamido-4-O-(2,6-di-O-benzyl-β-D-galactopyranosyl)-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside. Reaction of this diol with 1-O-(N-methyl) acetimidyl-2,3,4,6-tetra-O-benzyl-β-D-galactopyranose in nitromethane in the presence of toluene-p-sulphonic acid regiospecifically gave the derivative (15). The title trisaccharide was obtained after catalytic hydrogenolysis. The alcohol benzyl 2-acetamido-4-O-(2,3,6-tri-O-benzyl-β-D-galactopyranosyl)-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside was found to be unreactive under the same conditions.

Synthesis of O-α- l-fucopyranosyl-(1→2)- O-β- d-galactopyranosyl-(1→4)- d-glucopyranose (2′- O-α- l-fucopyranosyl-lactose)

Selective benzoylation of 2,3:5,6:3′,4′-tri- O-isopropylidenelactose dimethyl acetal ( 1) with benzoyl chloride in dichloromethane afforded the 6′- O-benzoyl derivative ( 2). The constitution of 2 was inferred from its n.m.r. spectrum, and confirmed by methylation and subsequent hydrolysis to 2- O-methyl- d-galactose and d-glucose. Glycosidation of 2 (catalyzed by bromide ion) with 2,3,4-tri- O-benzyl-α- l-fucopyranosyl bromide gave the 2′- O-linked, fully protected trisaccharide ( 9). O-Debenzoylation of 9, followed by deacetalation, furnished the tri- O-benzyl trisaccharide ( 11). Subsequent hydrogenolysis of the benzyl groups of 11 afforded the title trisaccharide. The acetal 1 was converted into a monoacetate and a dibenzoate, and a simple synthesis of 2′- O-methyl-lactose, starting from 1, is also described.

Synthesis of phenyl O-α- l-fucopyranosyl-(1→2)- O-β- d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-α- d-galactopyranoside

phenyl 2-acetamido-2-deoxy-4,6- O-( p-methoxybenzylidene)-3- O-[4,6- O-( p-methoxybenzylidene)-β- d-alactopyranosyl]-α- d-galactopyranoside ( 3) was prepared from phenyl 2-acetamido-2-deoxy-4,6- O-( p-methoxybenzylidene)-3- O-(2,3,4,6-tetra- O-acetyl-β- d-galactopyranosyl)-α- d-galactopyranoside by zemplén deacetylation, followed by reaction with p-methoxybenzaldehyde in the presence of anhydrous zinc chloride. The selective benzoylation of 3 gave the 3′-benzoate which, on condensation with 2,3,4-tri- O-benzyl-α- l-fucopyranosyl bromide under catalysis by halide ion, afforded a crystalline trisaccharide from which the title trisaccharide was obtained by debenzoylation followed by catalytic hydrogenolysis.

Practical synthesis of O-β- d-mannopyranosyl-, O-α- d-mannopyranosyl-, and O-β- d-glucopyranosyl-(1→4)- O-α- l-rhamnopyranosyl-(1→3)- d-galactoses

The koenigs-Knorr glycosylation of 4,6- O-ethylidene-1,2- O-isopropylidene-3- O-(2,3- O-isopropylidene-α- l-rhamnopyranosyl)-α- d-galactopyranose ( 3) by 4,6-di- O-acetyl-2,3- O-carbonyl-α- d-mannopyranosyl bromide ( 10), as well as Helferich glycosylations of 3 by tetra- O-acetyl-α- d-mannopyranosyl and -α- d-glucopyranosyl bromides, proceeded smoothly to give high yields of trisaccharide derivatives ( 12, 16, and 17). An efficient procedure for the transformation of 12, 16, and 17 into the α-deca-acetates of the respective trisaccharides has been developed. Zemplén de-acetylation then afforded the title trisaccharides in yields of 53, 52, and 62 %, respectively, from 3. A new route to 1,4,6-tri- O-acetyl-2,3- O-carbonyl-α- d-mannopyranose is suggested.

Synthesis of O-α l-fucopyranosyl-(1→3)- O-β- d-galactopyranosyl-(1→4)- d-glucose (3′- O-α- l-fucopyranosyllactose), and an Improved Route to its β-(1″→3′)-linked Isomer

Isopropylidenation of lactose with 2,2-dimethoxypropane in N, N-dimethyl-formamide at 80-85° gave a 1:2 mixture of the kinetically favored 4′,6′-acetal 1 and the thermodynamically more-stable 3′,4′-acetal 2, which were separated by chromatography. The 1,2,3,6,2′,6′-hexaacetate ( 3) and the 1,2,3,6,2′,6′-hexabenzoate ( 4) of 2, as well as the corresponding, deacetonated esters 5 and 6, were prepared by standard procedures. Condensation of 1,2,3,6,2′,6′-hexa- O-acetyl-α,β-lactose ( 5) with 2,3,4 tri- O-benzy1- l-fucopyranosyl bromide by the method of bromide-ion catalysis gave the α-(1″→3′)-linked, protected trisaccharide 8. Deacetylation followed by hydrogenolytic removal of the benzyl groups afforded the title trisaccharide 10. The hexaacetate 5 was also condensed with 2,3,4-tri- O-acetyl-α- l-fucopyranosyl bromide, under Koenigs-Knorr conditions, which provided an improved route to the corresponding, β-(1″→3′)-linked trisaccharide.

The synthesis of O-β- D-mannopyranosyl-(1→4)- O-(2-acetamido-2-deoxy-β- D-glucopyranosyl)-(1→4)-2-acetamido-2-deoxy- D-glucopyranose. part II

Allyl 2-acetamido-3,6-di- O-(2-butenyl)-2-deoxy-β- D-glucopyranoside was prepared, and coupled with 2-methyl-(4- O-acetyl-3,6-di- O-benzyl-1,2-dideoxy-α- D-glucopyrano)-[2,1- d]-2-oxazoline. The resulting, protected disaccharide allyl 2-acetamido-4- O-(2-acetamido-4- O-acetyl-3,6-di- O-benzyl-2-deoxy-β- D-glucopyranosyl)-3,6-di- O-(2-butenyl)-2-deoxy-β- D-glucopyranoside was O-deacetylated and the product coupled with 2- O-acetyl-3,4,6-tri- O-benzyl-α- D-glucopyranosyl bromide in the presence of silver trifluoromethanesulfonate and 1, 1,3,3-tetramethylurea, to give the trisaccharide, allyl O-(2- O-acetyl-3,4,6-tri- O-benzyl-β- D-glucopyranosyl)-(1→4)- O-(2-acetamido-3,6-di- O-benzyl-2-deoxy-β- D-glucopyranosyl)-(1→4)-2-acetamido-3,6-di- O-(2-butenyl)-2-deoxy-β- D-glucopyranoside. O-Deacetylation, oxidation with acetic anhydride-dimethyl sulfoxide, and stereoselective reduction with sodium borohydride gave mainly allyl O-(3,4,6-tri- O-benzyl-β- D-mannopyranosyl)-(1→4)- O-(2-acetamido-3,6-di- O-benzyl-2-deoxy-β- D-glucopyranosyl)-(1→4)-2-acetamido-3,6-di- O-(2-butenyl)-2-deoxy-β- D-glucopyranoside. Removal of the 2-butenyl groups was performed by treatment with potassium tert-butoxide in dimethyl sulfoxide, followed by isomerization of the allyl to a 1-propenyl group with tris(triphenyl-phosphine)rhodium chloride. Mild, acid treatment, and catalytic hydrogenation, gave the title trisaccharide.

ChemInform Abstract: CHEMICAL MODIFICATION OF LACTOSE. XII. PREPARATION OF O‐(2‐ACETAMIDO‐2‐DEOXY‐β‐D‐GLUCOPYRANOSYL)‐(1 → 6)‐O‐β‐D‐GALACTOPYRANOSYL‐(1 → 4)‐D‐GLUCOPYRANOSE (6′‐N‐ACETYLGLUCOSAMINYLLACTOSE)

AbstractDas Disaccharid (I) wird über die tritylierten Verbindungen (II) und (III) in das benzylierte Derivat (IV) übergeführt, das mit dem Oxazolin (V) das Trisaccharid (VI) liefert.

Synthesis of 2-acetamido-4-O-(2-acetamido-2-deoxy-.BETA.-D-glucopyranosyl)-2-deoxy-3-O-(.ALPHA.-L-fucopyranosyl)-D-glucopyranose (3-O-.ALPHA.-L-fucopyranosyl-di-N-acetylchitobiose).

A synthesis of the title trisaccharide (14) is reported. The first step of the synthetic route is stereospecific condensation of 2-acetamido-1, 6-anhydro-3-O-benzyl-2-deoxy-β-D-glucopyranose with 2-methyl-(3, 4, 6-tri-O-acetyl-1, 2-dideoxy-α-D-glucopyrano)-[2', 1' : 4, 5]-2-oxazoline to yield a fully protected β-D-(1→4)-linked disaccharide (8) bearing 2-acetamido-2-deoxy-D-glucopyranose (GlcNAc) at the non-reducing residue. After acetolysis of the 1, 6-anhydro ring of 8, the resulting fully-protected disaccharide is debenzylated to yield chitobiose heptaacetate (10) having a free hydroxyl group at the C-3 position of the reducing GlcNAc. Compound 10 is glycosylated with 2, 3, 4-tri-O-benzyl-α-L-fucopyranosyl bromide by a bromide ion-catalyzed reaction. After removing the protecting groups of the resulting trisaccharide by debenzylation and de-O-acetylation, an anomeric mixture of 14 is obtained as an amorphous solid. CMR spectral data for 14 are also presented.

Chemical modification of lactose. XII. Preparation of O-(2-acetamido-2-deoxy-.BETA.-D-glucopyranosyl)-(1.RAR.6)-O-.BETA.-D-galactopyranosyl-(1.RAR.4)-D-glucopyranose (6'-N-acetylglucosaminyllactose).

The title trisaccharide (16) is a constituent of the higher oligosaccharides in human milk. As part of our program of synthesis of oligosaccharides in human milk, the title trisaccharide was prepared. Heating of a mixture of 1, 6-anhydro-2, 2´, 3, 3´, 4´-penta-O-benzyl-β-lactose and 2-methyl-(3, 4, 6-tri-O-acetyl-1, 2-dideoxy-α-D-glucopyrano) [2, 1-d]-2-oxazoline in nitromethane-toluene in the presence of p-toluenesulfonic acid at 95° for 1 hr with stirring afforded the protected 1, 6-anhydro-β-derivative of 16 (6). The protecting groups of 6 were removed by catalytic hydrogenation followed by deacetylation, or vice versa, to afford the 1, 6-anhydro-β-derivative of 16 (9). Compound 9 gave a crystalline peracetate (14). The 1, 6-anhydro-β-ring of 14 was cleaved by mild acetolysis to afford an anomeric mixture of the peracetate of 16, from which the α-anomer (15) was isolated as needles. Deacetylation of 15 gave the title trisaccharide as a hygroscopic amorphous powder.

Synthesis of blood-group substances. Part 8. A synthesis of the branched trisaccharide 2-acetamido-2-deoxy-4-O-(α-L-fucopyranosyl)-3-O-(β-D-galactopyranosyl)-D-glucopyranose

Reaction of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide with benzyl 2-acetamido-4-O-allyl-6-O-benzyl-2-deoxy-α-D-glucopyranoside provided crystalline benzyl 2-acetamido-3-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-4-O-allyl-6-O-benzyl-2-deoxy-α-D-glucopyranoside in 87% yield. Deallylation followed by condensation with 1-O-(N-methyl) acetimidyl-2,3,4-tri-O-benzyl-β-L-fucopyranose provided the crystalline derivative (13). The title trisaccharide was obtained after O-deacetylation followed by catalytic hydrogenolysis. Preparations of 2-acetamido-2-deoxy-3-O-(β-D-galactopyranosyl)-D-glucopyranose and 2-acetamido-2-deoxy-4-O-(α-L-fucopyranosyl)-D-glucopyranose are reported.

Synthesis of blood-group substances. Part 7. Synthesis of the branched trisaccharide O-α-L-fucopyranosyl-(1 → 3)-[O-β-D-galactopyranosyl-(1 → 4)]-2-acetamido-2-deoxy-D-glucopyranose

Reaction of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide with benzyl 2-acetamido-3-O-allyl-6-O-benzyl-2-deoxy-α-D-glucopyranoside in 1,2-dichloroethane in the presence of mercuric bromide and molecular sieves (4 A) provided crystalline benzyl 2-acetamido-4-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-3-O-allyl6-O-benzyl-2-deoxy-α-D-glucopyranoside in 77% yield. Deallylation with chloro(tristriphenylphosphine)rhodium(I) followed by condensation with 2,3,4-tri-O-benzyl-α-L-fucopyranosyl bromide provided the derivative (14). The title trisaccharide was obtained after O-deacetylation followed by catalytic hydrogenolysis.

ChemInform Abstract: CHEMICAL MODIFICATION OF LACTOSE. IX. SYNTHESIS OF O‐β‐D‐GALACTOPYRANOSYL‐(1 → 6)‐O‐β‐D‐GALACTOPYRANOSYL‐(1 → 4)‐D‐GLUCOPYRANOSE (6′‐GALACTOSYLLACTOSE)

AbstractIn einer modifizierten Königs‐Knorr‐Reaktion liefert die Tetra‐O‐acetyl‐lö‐anhydro‐ β‐lactose (I) mit dem entsprechenden Tetra‐O‐acetyl‐a‐D‐galactopyranosylbromid bei anschließender Acetylierung das kristalline anhydro‐Trisaccharid (II), das über (III) in die im Titel genannte Verbindung (IV) übergeführt wird.

Chemical modification of lactose. IX. Synthesis of O-.BETA.-D-galactopyranosyl-(1.RAR.6)-O-.BETA.-D-galactopyranosyl-(1.RAR.4)-D-glucopyranose (6'-galactosyllactose).

The title trisaccharide was synthesized from 1, 6-anhydro-β-lactose. Condensation of 2, 2', 3, 3'-tetra-O-acetyl-1, 6-anhydro-β-lactose and 2, 3, 4, 6-tetra-O-acetyl-α-D-galactopyranosyl bromide by a modified Koenigs-Knorr reaction followed by acetylation gave acetylated 1, 6-anhydro-β-trisaccharide (3) in 62% yield. The β-configuration for the new galactosidic linkage was obtained from the value of the molecular rotation of 3. Deacetylation of 3 afforded 1, 6-anhydro-β-trisaccharide (4). The structure was determined by a gas chromatographic (GC) analysis and a gas chromatography-mass spectrometry of acid hydrolysate of permethylated 4. Acetolysis of 3 under mild condition proceeded cleavage of the 1, 6-anhydro-β-ring and afforded acetylated trisaccharide contaminated with acetylated galactose and lactose. From the acetolysis mixture, the title trisaccharide was isolated via acetylated β-trisaccharide followed by deacetylation. The structure was determined by GC analysis of the partial methylated alditol acetates obtained from the hydrolysate of permethylated, borohydride reduced trisaccharide.

Syntheses of O-.ALPHA.- and O-.BETA.-D-galactopyranosyl-(1.RAR.6)-O-[.ALPHA.-D-glucopyranosyl-(1.RAR.4)]-D-glucopyranoses.

The title new reducing trisaccharides were synthesized starting from 1, 6-anhydro-β-maltose. Reflux of 2, 2', 3, 3', 4'-penta-O-acetyl-1, 6-anhydro-β-maltose with 2, 3, 4, 6-tetra-O-benzyl-α-D-galactopyranosyl chloride in benzene in the presence of mercuric cyanide and Drierite stereospecifically afforded the corresponding trisaccharide derivative having α-D-(1→6) galactosidic linkage (yield 63%). After debenzylation with subsequent acetylation, acetolysis of the β-1, 6-anhydro linkage, and deacetylation, the former title trisaccharide was obtained. Stirring of 2, 2', 3, 3', 4'-penta-O-acetyl-1, 6-anhydro-6'-O-trityl-β-maltose with 2, 3, 4, 6-tetra-O-acetyl-α-D-galactopyranosyl bromide in nitromethane in the presence of silver perchlorate and Drierite, followed by acetylation stereospecifically yielded the corresponding trisaccharide derivative having β-D-(1→6) galactosidic linkage (yield 56%). Acetolysis of the β-1, 6-anhydro linkage, followed by deacetylation gave the latter title trisaccharide.

Synthesis of p-nitrophenyl 6- O-(2-acetamido-2-deoxy-β- d-glucopyranosyl)-β- d-galactopyranoside and p-nitrophenyl O-β- d-galactopyranosyl-(1→3)- O-(2-acetamido-2-deoxy-β- d-glucopyranosyl)-(1→6)-β- d-galactopyranoside

Condensation of 2-methyl-(3,4,6-tri- O-acetyl-1,2-dideoxy-α- d-glucopyrano)-[2′,1′:4,5]-2-oxazoline with p-nitrophenyl 2,3-di- O-acetyl-β- d-galactopyranoside ( 4), followed by saponification of the resulting disaccharide derivative, produced p-nitrophenyl 6- O-(2-acetamido-2-deoxy-β- d-glucopyranosyl)-β- d-galactopyranoside as a crystalline compound. Reaction of 2-methyl-[4,6-di- O-acetyl-1,2-dideoxy-3- O-(2,3,4,6-tetra- O-acetyl-β- d-galactopyranosyl)-α- d-glucopyrano]-[2′,1′:4,5]-2- oxazoline with 4 in a similar reaction-sequence provided the title trisaccharide compound.