- Convenient synthesis of D-talose from D-galactose
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The rare and expensive D-talose was conveniently synthesized from readily available D-galactose in four steps with an overall yield of 58%. The key step was the inversion of equatorial 2-OH of galactose to the axial one by S N2 reaction under the modified Lattrell-Dax reaction conditions.
- Xiao, Hualing,Wang, Guangfa,Wang, Peng,Li, Yingxia
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- DRUG DELIVERY
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A drug delivery vehicle comprising a vesicle conjugated to one or more targeting groups, wherein the targeting groups comprise an oligosaccharide which is Lewis A or Lewis B or a mimetic thereof, or a pharmaceutically acceptable salt or PEGylated form of the oligosaccharide : (I) wherein R represents the pointof attachment to the vesicle.10
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Page/Page column 29; 30
(2019/11/19)
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- SYNTHESIS AND USE OF GLYCODENDRIMER REAGENTS
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The present invention relates to a chemically modified mutant protein including a cysteine residue substituted for a residue other than cysteine n a precursor protein, the substituted cysteine residue being subsequently modified by reacting the cysteine residue with a glycosylated thiosulfonate. Also a method of producing the chemically modified mutant protein is provided. The present invention also relates to a glycosylated methanethiosulfonate. Another aspect of the present invention is a method of modifying the functional characteristics of a protein including providing a protein and reacting the protein with a glycosylated methanethiosulfonate reagent under conditions effective to produce a glycoprotein with altered functional characteristics as compared to the protein. In addition, the present invention relates to methods of determining the structure-function relationships of chemically modified mutant proteins. The present invention also relates to synthetic methods for producing thio-glycoses, the thio-glycoses so produced, and to methods for producing glycodendrimer reagents.
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Page/Page column 25; sheet 8
(2010/11/08)
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- Stereoselective synthesis of α-L-Fucp-(1,2)- and -(1,3)-β-D-Galp(1)-4-methylumbelliferone using glycosyl donor substituted by propane-1,3-diyl phosphate as leaving group
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Stereoselective synthesis of α-L-Fucp-(1,2)- and -(1,3)-β-D-Galp(1)-4-methyllumbelliferone was accomplished using glycosyl donor substituted by propane-1,3-diyl phosphate as leaving group. The α-stereochemistry for the anomeric centre was assigned on the basis of the observed 13C-H coupling constant of 165.4 Hz for the bond. The results suggested that the bond-forming reaction intermediate was formed through participation of the second carbon acetoxy function or by an SN2-like process.
- Vankayalapati, Hariprasad,Singh, Gurdial
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p. 2187 - 2193
(2007/10/03)
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- Carbohydrate Homologation by the Use of 2-(Trimethylsilyl)thiazole. Preparative Scale Synthesis of Rare Sugars: L-Gulose, L-Idose, and the Disaccharide Subunit of Bleomycin A2
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The well established one-carbon homologation method of protected monosaccharides employing 2-(trimethylsilyl)thiazole (2-TST) as a formyl anion equivalent has been used for high yield and multigram scale synthesis of the title rare hexoses from L-xylose. Thus, L-gulose has been obtained by stereoselective anti-addition of 2-TST to aldehydo-L-xylose diacetonide followed by thiazole to formyl conversion of the resulting alcohol. The inversion of configuration at C-1 of this alcohol by an oxidation - reduction sequence prior to the aldehyde releasing from thiazole led to L-idose. The same alcohol was readily elaborated into 1,3,4,6-tetra-O-acetyl-L-gulopyranose whose highly stereoselective glycosidation coupling with 3-O-carbamoyl-2,4,6-tri-O-acetyl-α-D-mannosyl diethyl phosphate afforded the same peracetylated disaccharide subunit employed by Boger and Honda in the total synthesis of the antibiotic bleomycin A2.
- Dondoni, Alessandro,Marra, Alberto,Massi, Alessandro
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p. 6261 - 6267
(2007/10/03)
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- Stereoselective ring-opening of acetylated pyranose-1,2-(ethyl orthoacetates)
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When acetylated pyranose-1,2-(ethyl orthoacetates) were hydrolyzed in acidic solvents, the ring-opening of the orthoacetate rings was influenced by the axial or equatorial OAc group at C-4 on the pyranoses; on acid-catalyzed hydrolysis, 3,4,6-tri-O-acetyl-α-D-galactopyranose- (8) and methyl 3,4-di-O-acetyl-α-D-galacturonatopyranose-1,2-(ethyl orthoacetate) (16) having an axial OAc group at C-4 on the pyranose rings gave 1,3,4,6-tetra-O-acetyl-α-D-galactopyranose (9) and methyl 1,3,4-tri-O-acetyl-α-D-galacturonatopyranose (23), respectively, whereas 3,4,6-tri-O-acetyl-α-D-glucopyranose- (10) and methyl 3,4-di-O-acetyl-α-D-glucuronatopyranose-1,2-(ethyl orthoacetate) (22) having an equatorial OAc group at C-4 on the pyranose rings gave 2,3,4,6-tetra-O-acetyl-D-glucopyranose (11) and methyl 2,3,4-tri-O-acetyl-D-glucuronatopyranose (24), respectively. On the acid-catalyzed hydrolysis, 3,4-di-O-acetylβ-L-arabinopyranose-1,2-(ethyl orthoacetate) (34) having an axial OAc group at C-4 on the pyranose ring gave a mixture of 1,3,4-tri-O-acetyl-β-L- (35) and 2,3,4-tri-O-acetyl-L-arabinopyranose (36). These selectivities of ring-opening of the 1,2-(orthoacetates) were considered to have resulted from the differences of the conformers of the 1,2-(orthoacids) intermediates derived from the 1,2-(orthoacetates) and the orientation of the acetyl groups at C-4 on the pyranose rings.
- Saito,Sumita,Ichinose,Kanda
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