Selective tritylation of methyl β-sophoroside (1) and subsequent acetylation gave the 3,4,2′,3′,4′-penta-O-acetyl-6,6′-di-O-trityl derivative, which was O-detritylated, and the product p-toluenesulfonylated, to give methyl 3,4,2′,3′,4′-penta-O-acetyl-6,6′-di-O-p-tolylsulfonyl-β-sophoroside (4) in 63% net yield. Compound 4 was also obtained in 69% yield by p-toluenesulfonylation of 1, followed by acetylation. Several, 6,6′-disubstituted derivatives of 1 were synthesized by displacement reactions of 4 with various nucleophiles. Treatment of 4 with sodium methoxide afforded methyl 3,6:3′,6′-dianhydro-β-sophoroside. Several 6- and 6′-monosubstituted derivatives of 1 were prepared, starting from the 4,6-O-benzylidene derivative of 1. 相似文献
Preparation of the following glycosides is described: 2-aminoethyl β-d-glycosides of (A) 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-d-glucopyranose, (B) 2-acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-β-d-glucopyranose (N,N′-diacetylchitobiose pentaacetate), (C) 4-O-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-2,3,6-tri-O-acetyl-β-d-glucopyranose (cellobiose heptaacetate); 8-carboxyoctyl glycosides of (D) cellobiose, and (E) N,N′-diacetylchitobiose. Conjugates were prepared from (A), (B), and (C) by coupling to bovine serum albumin by cyanuric trichloride and subsequent deacetylation; (D) and (E) were coupled to bovine serum albumin by the mixed-anhydride reaction. Conjugates (A) and (B) were insoluble; conjugates (C), (D), and (E) functioned as artificial antigens and gave rise to precipitating antibodies in rabbits. Specificities of the antisera were determined by inhibition studies. 相似文献
2-Methyl-[3,6-di-O-acetyl-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-α-d-glucopyrano]-[2,1-d]-2-oxazoline (4) was prepared from 2-acetamido-3,6-di-O-acetyl-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-α-d- glucopyranosyl chloride. Condensation of 3,4:5,6-di-O-isopropylidene-d-mannose dimethyl acetal with 4 in the presence of a catalytic amount of p-toluenesulfonic acid afforded O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-(1 → 4)-O-(2-acetamido-3,6-di-O-acetyl-2-deoxy-β-d-glucopyranosyl)-(1 → 2)-3,4:5,6-di-O-isopropylidene-d-mannose dimethyl acetal (6) in 8.6% yield. Catalytic deacetylation of 6 with sodium methoxide, followed by hydrolysis with dilute sulfuric acid, gave O-β-d-galactopyranosyl-(1 → 4)-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1 → 2)-d-mannose (7). The inhibitory activities of 7 and related sugars against the hemagglutinating activities of various lectins were assayed, and 7 was found to be a good inhibitor against Phaseolus vulgaris hemagglutinin. 相似文献
Condensation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside with 2,3,4,6-tetra-O-benzyl-1-O-(N-methyl)acetimidoyl-β-D-glucopyranose gave benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-α-D-glucopyranoside which was catalytically hydrogenolysed to crystalline 2-acetamido-2-deoxy-4-O-α-D-glucopyranosyl-α-D-glucopyranose (N-acetylmaltosamine). In an alternative route, the aforementioned imidate was condensed with 2-acetamido-3-O-acetyl-1,6-anhydro-2-deoxy-β-D-glucopyranose, and the resulting disaccharide was catalytically hydrogenolysed, acetylated, and acetolysed to give 2-acetamido-1,3,6-tri-O-acetyl-2-deoxy-4-O-(2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl)-α-D-glucopyranose Deacetylation gave N-acetylmaltosamine. The synthesis of 2-acetamido-2-deoxy-4-O-β-D-glucopyranosyl-α-D-glucopyranose involved condensation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide in the presence of mercuric bromide, followed by deacetylation and catalytic hydrogenolysis of the condensation product. 相似文献
A lactosaminyl donor, 3,6-di-O-acetyl-2-deoxy-2-phthalimido-4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-β-d- glucopyranosyl chloride, was synthesized in 10 steps, starting from 1,3,4,6-tetra-O-acetyl-2-deoxy-2-phthalimido-β-d-glucopyranose. Benzyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranoside was prepared by regioselective benzylation at the primary hydroxyl group by the stannyl method, and was used as a key intermediate. 相似文献
Treatment of methyl 3-O-acetyl-4,6-O-benzylidene-α-D-glucopyranoside 2-chlorosulphate (2), 3,4,6,3′,4′,6′-hexa-O-acetylsucrose 2,1′-bis(chlorosulphate), 3,4,6,3′,4′,6′-hexa-O-acetyl-1′-O-benzoylsucrose 2-chlorosulphate, and 3,4,3′,4′-tetra-O-acetyl-6,6′-dichloro-6,6′-dideoxysucrose 2,1′-bis(chlorosulphate) with lithium chloride in hexamethylphosphoric triamide gave the corresponding chlorodeoxy-manno derivatives. Treatment of the 2-chlorosulphate 2 with such nucleophilic reagents as lithium bromide, sodium azide, sodium chloride, and sodium benzoate in hexamethylphosphoric triamide gave the 2-hydroxy compound as a major product. Selective chlorination at C-1′ was achieved when 3,4,6,3′,4′,6′-hexa-O-acetylsucrose was treated with sulphuryl chloride in a mixture of pyridine and chloroform. 相似文献
The 2,1′-O-isopropylidene derivative (1) of 3-O-acetyl-4,6-O-isopropylidene-α-d-glucopyranosyl 6-O-acetyl-3,4-anhydro-β-d-lyxo-hexulofuranoside and 2,3,4-tri-O-acetyl-6-O-trityl-α-d-glucopyranosyl 3,4-anhydro-1,6-di-O-trityl-β-d-lyxo-hexulofuranoside have been synthesised and 1 has been converted into 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-d-lyxo-hexulofuranoside (2). The SN2 reactions of 2 with azide and chloride nucleophiles gave the corresponding 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-azido-4-deoxy-β-d-fructofuranoside (6) and 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-chloro-4-deoxy-β-d-fructofuranoside (8), respectively. The azide 6 was catalytically hydrogenated and the resulting amine was isolated as 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 4-acetamido-1,3,6-tri-O-acetyl-4-deoxy-β-d-fructofuranoside. Treatment of 5 with hydrogen bromide in glacial acetic acid followed by conventional acetylation gave 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,3,6-tri-O-acetyl-4-bromo-4-deoxy-β-d-fructofuranoside. Similar SN2 reactions with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-d-ribo-hexulofuranoside (12) resulted in a number of 4′-derivatives of α-d-glucopyranosyl β-d-sorbofuranoside. The regiospecific nucleophilic substitution at position 4′ in 2 and 12 has been explained on the basis of steric and polar factors. 相似文献
Reaction of 6-O-acetylsucrose1 with sulphuryl chloride in chloroform-pyridine affords, after dechlorosulphation and acetylation, a mixture of two isomeric 2,3,6-tri-O-acetyl-4-chloro-4-deoxy-α-d-galactopyranosyl 3-O-acetyl-1,4,6-trichloro-1,4,6-trideoxy-β-d-hexulofuranosides (6 and 7) and 2,3,6-tri-O-acetyl-4-chloro-4-deoxy-α-d-galactopyranosyl 3,4-di-O-acetyl-1,6-dichloro-1,6-dideoxy-β-d-fructofuranoside (4). Chlorination of C-4, C-1′, and C-6′ occurs by direct displacement of the initially formed chlorosulphonyloxy groups by chloride ions, but displacement of the 4′-chlorosulphate is sterically hindered. The introduction of a 4′-chloro substituent involves ring opening of intermediate 3′,4′-epoxides by chloride ions, the ribo-epoxide producing the sorbo-isomer 6 and the lyxo-epoxide giving the fructo-isomer 7. The proposed mechanism is supported by the formation of 4-chloro-4-deoxyfructofuranosides when 3′,4′-lyxo-hexulofuranosides are treated with sulphuryl chloride under the same conditions. 相似文献
Allyl 4-O-(4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-β-d-galactopyranosyl)-2-O-benzoyl-3,6-di-O-benzyl-α-d- galactopyranoside was O-deallylated to give the 1-hydroxy derivative, and this was converted into the corresponding 1-O-(N-phenylcarbamoyl) derivative, treatment of which with dry HCl produced the α-d-galactopyranosyl chloride. This was converted into the corresponding 2,2,2-trifluoroethanesulfonate, which was coupled to allyl 2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranoside, to give crystalline allyl 4-O-[4-O-(4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-β-d-galactopyranosyl)-2-O-benzoyl-3,6-di- O-benzyl-β-d-galactopyranosyl]-2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranoside (15) in 85% yield, no trace of the α anomer being found. The trisaccharide derivative 15 was de-esterified with 2% KCN in 95% ethanol, and the product O-debenzylated with H2-Pd, to give the unprotected trisaccharide. Alternative sequences are discussed. 相似文献
O-α-d-Mannopyranosyl-(1→6)-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→4)-2-acetamido-N-(l-aspart-4-oyl)-2-deoxy-β-d-glucopyranosylamine (12), used in the synthesis of glycopeptides and as a reference compound in the structure elucidation of glycoproteins, was synthesized via condensation of 2,3,4,6-tetra-O-acetyl-α-d-mannopyranosyl bromide with 2-acetamido-4-O-(2-acetamido-3-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-β-d-glucopyranosyl azide (5) to give the intermediate, trisaccharide azide 7. [Compound 5 was obtained from the known 2-acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-β-d-glucopyranosyl azide by de-O-acetylation, condensation with benzaldehyde, acetylation, and removal of the benzylidene group.] The trisaccharide azide 6 was then acetylated, and the acetate reduced in the presence of Adams' catalyst. The resulting amine was condensed with 1-benzyl N-(benzyloxycarbonyl)-l-aspartate, and the O-acetyl, N-(benzyloxycarbonyl), and benzyl protective groups were removed, to give the title compound. 相似文献
2-O-Benzoyl-3,6-di-O-benzyl-4-O-(chloroacetyl)-, 4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-, and 2-O-benzoyl-3,4,6-tri-O-benzyl-α-d-galactopyranosyl chloride were converted into the corresponding 2,2,2-trifluoroethanesulfonates, and these were treated with allyl 2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranoside, to give allyl 2-O-benzoyl-4-O-[2-O-benzoyl-3,6-di-O-benzyl-4-O-(chloroacetyl)-β-d-galactopyranosyl]-3,6-di-O-benzyl- α-d-galactopyranoside (26; 41% yield), allyl 4-O-(4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-β-d-galactopyranosyl)-2-O-benzoyl-3,6-di-O-benzyl- α-d-galactopyranoside (27; 62% yield), and allyl 2-O-benzoyl-4-O-(2-O-benzoyl-3,4,6-tri-O-benzyl-β-d-galactopyranosyl)-3,6-di-O-benzyl-α-d-galactopyranoside (28; 65% yield). All disaccharides were free from their α anomers. Disaccharides 26 and 27 were found to be base-sensitive, and were de-esterified by KCN in aqueous ethanol, and debenzylated with H2-Pd. Attempts to produce (1→4)-β-d-galactopyranosides from the coupling of a number of fully esterified d-galactopyranosyl sulfonates to allyl 2,3,6-tri-O-benzoyl-α-d-galactopyranoside were unsuccessful. 相似文献
The aminocyclitol antibiotic neamine has been chemically modified at the hydroxyl group on C-6 of the 2-deoxystreptamine moiety. The partially acetylated neamine derivatives, 6,3′,4′-tri-O-acetyl- (3) and 5,3′,4′-tri-O-acetyl-1,3,2′,6′-tetra-N-(ethoxycarbonyl)neamine (4), were prepared by random hydrolysis of the 5,6-O-ethoxyethylidene derivative (2), followed by chromatographic purification. Condensation of 4 and 2,3,5-tri-O-benzoyl-d-ribofuranosyl chloride led to 6-O-(β-d-ribofuranosyl)neamine (7). Analogous condensation of 4 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide or 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide afforded the corresponding 6-O-(d-hexopyranosyl)neamines. 相似文献
Benzylidenation of β-maltose monohydrate with α,α-dimethoxytoluene in N,N-dimethylformamide in the presence of p-toluenesulfonic acid gave, in 70% yield, 4′,6′-O-benzylidenemaltose, which was acetylated to afford, 1,2,3,6,2′,3′-hexa-O-acetyl-4′,6′-O-benzylidene-β-maltose (4). Removal of the benzylidene group of 4 gave 1,2,3,6,2′,3′-hexa-O-acetyl-β-maltose (5), which was transformed into 1,2,3,6,2′,3′,4′-hepta-O-acetyl-6′-O-p-tolylsulfonyl-β-maltose (8). Several 6′-substituted β-maltose heptaacetates were synthesized by displacement reactions of 8 with various nucleophiles. Condensation of 5 with 2,3,4,6-tetra-O-benzyl-α-d-glucopyranosyl bromide, under catalysis by halide ion, followed by removal of protecting groups, furnished panose in good yield. 相似文献
In continuation of our chemosystematic study of Stachys (Labiatae) we have isolated the previously reported isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (1) and 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (4) and four new allose-containing flavonoid glycosides from S. anisochila. The new glycosides are hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranside] (6) as well as the three corresponding diacetyl analogues of 1, 4 and 6, isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside], 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside] and hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside]. Extensive two-dimensional NMR studies (proton-carbon correlations, COSY experiments) allowed assignment of all 1H NMR sugar signals and a correction of the 13C NMR signal assignments for C-2 and C-3 of the allose. 相似文献
2-Acetamido-4-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-2-deoxy-α-d-glucopyranosyl phosphate, pure according to thin-layer and gas—liquid chromatography, optical rotation, and treatment with alkaline phosphatase and 2-acetamido-2-deoxy-β-d-glucosidase, was prepared by treatment of 2-methyl-[4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-1,2-dideoxy-α-d-glucopyrano]-[2,1-d]-2-oxazoline with dibenzyl phosphate, followed by the removal of the benzyl groups by catalytic hydrogenolysis, and O-deacetylation. In contrast, a sample prepared by the phosphoric acid procedure was shown to consist mainly of the β anomer. 2-Acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-α-d-glucopyranosyl phosphate was treated wit P1-diphenyl P2-dolichyl pyrophosphate to give a fully acetylated pyrophosphoric diester, which was O-deacetylated to give P1-2-acetamido-4-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-2-deoxy-α-d-glucopyranosyl P2-dolichyl pyrophosphate. This compound could be separated from the β anomer by t.l.c., and its behavior under dilute acid and alkaline conditions was investigated. 相似文献
A convenient method of synthesis of 1,6-anhydro-4-deoxy-2-O-tosyl-4-fluoro-β-D-glucopyranose by fusion of 1,6;3,4-dianhydro-2-O-tosyl-β-D-galactopyranose with 2,4,6-trimethylpyridinium fluoride was found. By a successive action of ammonia, methyl trifluoroacetate, and acetic anhydride, the resulting compound was transformed into 1,6-anhydro-3-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-β-D-glucopyranose, which was converted into 3,6-di-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-αD-glucopyranosyl fluoride by the reaction with HF/Py. The resulting fluoride was further used as a glycosyl donor in the synthesis of methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-β-D-glucosaminide. 相似文献
Trans-khellactone, cis-khellactone, 3′-senecioyl-cis-khellactone, 3′-senecioyl-4′-acetyl-cis-khellactone, 4′-senecioyl-cis-khellactone, 3′-acetyl-4′-senecioyl-cis-khellactone, 3′,4′-di-isovaleryl-cis-khellactone, 3′,4′-disenecioyl-cis-khellactone, 3′-angeloyl-4′-isovaleryl-cis-khellactone and 3′-isovaleryl-4′-angeloyl-cis-khellactone were obtained from the aerial part of Seseli tortuosum. 相似文献
3,6-Anhydro-α-D-galactopyranose 1,2-(methyl orthoacetate) and its 4-acetate were synthesized from 2,3,4-tri-O-acetyl-6-O-tosyl-α-D-galactopyranosyl bromide. Condensation of the above-mentioned, acetylated ortho ester with 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose gave 6-O-(2,4-di-O-acetyl-3,6-anhydro-β-D-galactopyranosyl)-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose. The same disaccharide derivative was synthesised from 6-O-β-D-galactopyranosyl-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose by mono-O-tosylation followed by treatment with alkali and acetylation. 相似文献
Silver trifluoromethanesulfonate-promoted condensation of 3,4,6-tri-O-acetyl-2-deoxy-phthalimido-β-d-glucopyranosyl bromide with benzyl 3,6-di-O-benzyl-α-d-mannopyranoside and benzyl 3,4-di-O-benzyl-α-d-mannopyranoside gave the protected 2,4- and 2,6-linked trisaccharides in yields of 54 and 32%, respectively. After exchanging the 2-deoxy-2-phthalimido groups for 2-acetamido-2-deoxy groups and de-blocking, the trisaccharides 2,4-di-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-d-mannose and 2,6-di-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-d-mannose were obtained. Similar condensation of 3,6-di-O-acetyl-2-deoxy-2-phthalimido-4-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-β-d-glucopyranosyl bromide with benzyl 3,4-di-O-benzyl-α-d-mannopyranoside gave a pentasaccharide derivative in 52% yield. After transformations analogous to those applied to the trisaccharides, 2,6-di-O-[β-d-galactopyranosyl-(1→4)-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)]-d-mannose was obtained. 相似文献