63000-71-5Relevant academic research and scientific papers
Iterative one-pot syntheses of chitotetroses
Huang, Lijun,Wang, Zhen,Li, Xiaoning,Ye, Xin-shan,Huang, Xuefei
, p. 1669 - 1679 (2007/10/03)
Rapid syntheses of chitotetrose derivatives were achieved in good yields using the newly developed reactivity independent iterative one-pot strategy. The protective groups on donors and acceptors were independently evaluated allowing matching of the two p
Synthesis of the Sda determinant and two analogous tetrasaccharides.
van Seeventer,Kamerling,Vliegenthart
, p. 181 - 195 (2007/10/03)
To contribute to the possibility of studying in greater detail the biological significance of Sda-containing glycans as occur in Tamm-Horsfall glycoprotein, the following three spacer-linked tetrasaccharides have been synthesized: the Sda determinant alpha-Neu p5Ac-(2-->3)-[beta- D-GalpNAc-(1-->4)]-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->O)(CH2)5NH 2 (1), the Gal-analogue alpha-Neup5Ac-(2-->3)-[beta-D-Galp-(1-->4)]-beta-D-Galp-(1-->4) -beta-D-GlcpNAc-(1-->O)(CH2)5NH2 (2), and the GlcNAc-analogue alpha-Neup5Ac-(2-->3)-[beta-D-GlcpNAc-(1-->4)]- beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->O)(CH2)5NH2 (3). The general trisaccharide acceptor 5-azidopentyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy- D-glycero-alpha-D-galactonon-2-ulopyranosylonate)-(2-->3)-(2 ,6-di-O-benzyl- beta-D-galactopyranosyl)-(1-->4)-3,6-di-O- benzyl-2-deoxy-2-phthalimido-beta-D-glucopyranoside was prepared, using methyl (phenyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero-D-galacto- non- 2-ulopyranosid)- onate as the sialyl donor. For the syntheses of 1, 2, and 3 the glycosyl donors 3,4,6-tri-O- acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide, 2,3,4,6-tetra-O-acetyl-alpha-D- galactopyranosyl bromide, and 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido -beta-D-glucopyranosyl trichloroacetimidate, respectively, proved to be the most suitable.
Synthesis of N-Acetylallosamine-Derived Disaccharides
Maloisel, Jean-Luc,Vasella, Andrea
, p. 1491 - 1514 (2007/10/02)
The protected disaccharide 44, a precursor for the synthesis of allosamidin, was prepared from the glycosyl acceptor 8 and the donors 26-28, best yields being obtained with the trichloroacetimidate 28 (Scheme 6).Glycosidation of 8 or of 32 by the triacetylated, less reactive donors 38-40 gave the disaccharides 46 and 45, respectively, in lower yields (Scheme 7).Regioselective glycosidation of the diol 35 by the donors 38-40 gave 42, the axial, intramolecularly H-bonded OH-C(3) group reacting exclusively (Schmeme 5).The glycosyl acceptor 8 was prepared from 9 by reductive opening of the dioxolane ring (Scheme 3).The donors 26-28 were prepared from the same precursor 9 via the hemiacetal 25.To obtain 9, the known 10 was de-N-acetylated (-> 18), treated with phthalic anhydride (-> 19), and benzylated, leading to 9 and 23 (Schemes 2 and 3).Saponification of 23, followed by acetylation also gave 9.Depending upon the conditions, acetylation of 19 yielded a mixture of 20 and 21 or exclusively 20.Deacetylation of 20 led to the hydroxyphthalimide 22.De-N-acetylation of the 3-O-benzylated α-D-glycosides 11 and 15, which were both obtained from 10, was very sluggish and accompanied by partial reduction of the O-allyl to an O-propyl group (Scheme 2).The β-D-glycoside 30 behaved very similarly to 11 and 15.Reductive ring opening of 31, derived from 29, yielded the 3-O-acetylated acceptor 32, while the analogous reaction of the α-D-anomer 20 was accompanied by a rapid 3-O -> 4-O acyl migration (-> 34; Scheme 4).Reductive ring opening of 21 gave the diol 35.The triacetylated donors 38-40 were obtained from 20 by debenzylidenation, acetylation (-> 36), and deallylation (-> 37), followed by either acetylation (-> 38), treatment with Me3SiSEt (-> 39), or Cl3CCN (-> 40).
