2771-48-4Relevant articles and documents
An improved procedure for the analysis of linkage positions in 2- acetamido-2-deoxy-D-glucopyranosyl residues by the reductive-cleavage method
D'Ambra,Gray
, p. 115 - 125 (1994)
The conditions of the reductive-cleavage method were modified to allow simultaneous analysis of 2-acetamido-2-deoxy-D-glucopyranosyl residues and monosaccharides of other classes. Methyl 2-deoxy-3,4,6-tri-O-methyl-2-(N- methylacetamido)-β-D-glucopyranoside was found to undergo transglycosidation under reductive-cleavage conditions when the reaction was quenched with an alcohol. Transglycosidation proceeded via an oxazolinium-ion intermediate, which then acted as a glycosyl donor to form an anomerically pure product. Time-course studies showed that in the presence of trimethylsilyl trifluoromethanesulfonate (Me3SiOSO2CF3), 4 h were required for complete conversion of the substrate into this intermediate, which was then trapped with methanol-d4. When the reaction was conducted in the presence of a mixture of trimethylsilyl methanesulfonate (Me3SiOSO2Me) and boron trifluoride etherate (BF3·OEt2) or with BF3·OEt2 alone, 24 h and 48 h, respectively, were required for complete conversion. The α anomer was unreactive after 24 h under all conditions, confirming earlier results. Reaction with racemic 2-butanol yielded a pair of diastereomers, in a 1:1 ratio, which were distinguishable by their GLC retention times and their 1H NMR spectra. Reaction with (S)-2-butanol gave only one of the diastereomeric products. These experiments demonstrated the feasibility of using the reductive-cleavage method to determine the absolute configuration of 2- acetamido sugars. The condition of the reductive-cleavage method were modified to allow simultaneous analysis of 2-acetamido-2-deoxy-D-glycopyranosyl residues and monosaccharides. These experiments demonstrated the feasibility of using the reductive-cleavage method to determine the absolute configuration of 2-acetamido sugars.
Chemoenzymatic Synthesis of Glycoconjugates Mediated by Regioselective Enzymatic Hydrolysis of Acetylated 2-Amino Pyranose Derivatives
Zheng, Changping,Bavaro, Teodora,Tengattini, Sara,Mascherpa, Andrea Gualla,Sollogoub, Matthieu,Zhang, Yongmin,Terreni, Marco
, p. 3622 - 3631 (2019/06/17)
Highly regioselective deprotection of a series of 2-amino pyranose building blocks was achieved by enzymatic hydrolysis. These monodeprotected intermediates were successfully used in the synthesis of a variety of glycoconjugate derivatives with a core of glucosamine or galactosamine, including neo-glycoproteins and glycosphingolipids. The hydrolysis catalyzed by acetylxylan esterase from Bacillus pumilus (AXE) is suitable for the synthesis of neo-glycoproteins with an N-acetyl glucosamine core. The hydrolysis catalyzed by Candida rugosa lipase (CRL) was successfully applied in the preparation of new sialylated glycolipids starting from glucosamine building blocks protected as phthalimide. This chemoenzymatic approach can be used for the preparation of new glycoconjugate products with anticancer activity.
Direct glycosylation of unprotected and unactivated sugars using bismuth nitrate pentahydrate
Polanki, Innaiah K.,Kurma, Siva H.,Bhattacharya, Asish K.
, p. 196 - 205 (2015/06/08)
Bi(NO3)3, a low-cost, mild, and environmentally green catalyst, has been successfully utilized for Fischer glycosylation for the synthesis of alkyl/aryl glycopyranosides by reacting unprotected sugars, namely, D-glucose, L-rhamnose, D-galactose, D-arabinose, and N-acetyl-D-glucosamine with various alcohols in good to excellent yields. The glycosides were formed with high α-selectivity. Further, an expedient separation of α- and β-glycosides using silver nitrate-impregnated silica gel flash liquid chromatography has been developed.
Iminosugar glycoconjugates
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Page/Page column 5, (2008/06/13)
The iminosugar conjugates according to the invention are N-alkylated 1,5-dideoxy-1,5-iminohexitol or 1,5-dideoxy-1,5-iminopentitol derivatives. The iminosugar component can be, for example, D-gluco-, L-ido-, D-galacto-, D-manno-, 2-acetamido-2-deoxy-D-gluco- or xylo-configuration. The N-substituent is a protected L-α-aminoacid derivative, showing L-lysine-like structural features. The linkage between the carbohydrate and the peptide component is not via the usual glycosidic position, but shows structural features of a very stable tertiary amine. Thus the linkage is very stable. These new compounds are synthesised by using catalytic intramolecular reductive amination of dicarbonyl sugars with partially protected amino acids. The process of intramolecular reductive amination itself is carried out using Pearlman's catalyst (Pd(OH)2/C) and H2 at ambient pressure and room temperature. The resulting accessible class of iminosugar conjugate compounds is represented by the general structure shown in Figure 4(c). The alkyl chain length parameter n can be freely chosen from n=0 upwards. Preferably n is between 0 and 10, and more preferably n is 2, 3, or 4. Residue R1 can be chosen from H, OH, or NHAc, with Ac being Acetyl. R2 can be H, OH, or NHAc. R3, R4, R5, R6 can be H or OH. R7 and R8 can be H, CH2OH CH3, COQH, or COOR with R being Alkyl or Aryl. R9 and R10 can be chosen from H, NH2, NHR, with R being a protective group, an amino acid, a peptide, or a protein. R11 can be OH, O-Alkyl, O-Aryl, NH2, N-Alkyl, N-Aryl, amino acid or peptide, connected via an amide bond.
