Chemical synthesis of sulfated oligosaccharides with a β-d-Gal-(1→3)-[β-d-Gal-(1→4)-(α-l-Fuc-(1→3)-β-d-GlcNAc-(1→6)]-α-d-GalNAc sequence
作者:Jie Xia、T. Srikrishnan、James L. Alderfer、R.K. Jain、Conrad F. Piskorz、Khushi L. Matta
DOI:10.1016/s0008-6215(00)00211-1
日期:2000.11
β- d -Gal6SO 3 Na-(1→3)-[β- d -Gal-(1→4)-α- l -Fuc-(1→3)-β- d -GlcNAc-(1→6)]-α- d -GalNAc→OMe ( 1 ) and β- d -Gal6SO 3 Na-(1→3)-[β- d -Gal-(1→4)-α- l -Fuc-(1→3)-β- d -GlcNAc6SO 3 Na-(1→6)]-α- d -GalNAc→OMe ( 2 ) by using Lewis X trisaccharides 12 and 16 as glycosyl donors are described. Sulfated oligosaccharides 1 – 2 and intermediate compounds are fully characterized by 2D 1 H– 1 H DQF-COSY and 2D
摘要两种硫酸五糖的合成:β-d -Gal6SO 3 Na-(1→3)-[β-d-Gal-(1→4)-α-1-Fuc-(1→3)-β-d -GlcNAc-(1→6)]-α-d -GalNAc→OMe(1)和β-d -Gal6SO 3 Na-(1→3)-[β-d-Gal-(1→4)-α-通过使用路易斯X三糖12和16作为糖基供体,描述了1-Fuc-(1→3)-β-d-GlcNAc6 SO 3 Na-(1→6)]-α-d-GalNAc→OMe(2)。通过2D 1 H-1 H DQF-COSY和2D ROESY实验可以充分表征硫酸化的寡糖1-2和中间化合物。
Total synthesis of a sialylated and sulfated oligosaccharide from O-linked glycoproteins
作者:Jie Xia、Conrad F Piskorz、James L Alderfer、Robert D Locke、Khushi L Matta
DOI:10.1016/s0040-4039(00)00261-6
日期:2000.4
The totalsynthesis of a sialylated and sulfatedoligosaccharide 1 representative of a structure occurring in respiratory mucins has been accomplished. Our strategy depends upon the employment of 2-naphthymethyl (NAP) protection for hydroxyl functions. Choice of the well-defined sialyl donor 15 was made because of its enhanced reactivity over the parent compound 14 for glycosylation.
Total syntheses of the GlyCAM-1 (glycosylation-dependent cell adhesion molecule-1) oligosaccharide structures: [alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 4)-[alpha-Fuc-(1 --> 3)]-beta-(6-O-SO3Na)-GlcNAc-(1 --> 6)]-[alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 3)]-alpha-GalNAc-OMe (1) and [alpha-NeuAc-(2 --> 3)-beta-Gal-(1 --> 4)-[alpha-Fuc-(1 --> 3)]-beta-GlcNAc-(1 --> 6)]-[alpha-NeuAc-(2 3)-beta-Gal-(1 --> 3)]-alpha-GalNAc-OMe (2) through a novel sialyl LewisX tetrasaccharide donor are described. Employing sequential glycosylation strategy, the starting trisaccharide was regio- and stereoselectively constructed through coupling of a disaccharide imidate with the monosaccharide acceptor phenyl-6-O-naphthylmethyl-2-deoxy-2-phthalimido-1-thio-beta-D-glucopyranoside with TMSOTf as a catalyst without affecting the SPh group. The novel sialyl Lewisx tetrasaccharide donor 3 was then obtained by alpha-L-fucosylation of trisaccharide acceptor with the 2,3,4-tri-O-benzyl-1-thio-beta-L-fucoside donor. The structure of the novel sialyl Lewisx tetrasaccharide was established by a combination of 2D DQF-COSY and 2D ROESY experiments. Target oligosaccharides 1 and 2 were eventually constructed through heptasaccharide which was obtained by regioselective assembly of advanced sialyl Lewisx tetrasaccharide donor 3 and a sialylated trisaccharide acceptor in a predictable and controlled manner. Finally, target heptasaccharides 1 and 2 were fully characterized by 2D DQF-COSY, 2D ROESY, HSQC, HMBC experiments and FAB mass spectroscopy.
Use of 1,2-dichloro 4,5-dicyanoquinone (DDQ) for cleavage of the 2-naphthylmethyl (NAP) group
作者:Jie Xia、Saeed A Abbas、Robert D Locke、Conrad F Piskorz、James L Alderfer、Khushi L Matta
DOI:10.1016/s0040-4039(99)02046-8
日期:2000.1
The 2-naphthylmethyl (NAP) group is a versatile group for protection of hydroxyl functions. It is stable to 4% TFA in CHCl3, hot 80% HOAc-H2O, SnCl2-AgOTf and HCl-EtOH, but it can readily be removed with DDQ in CH2Cl2. (C) 1999 Elsevier Science Ltd. All rights reserved.