2,3,4,6-Tetra-O-acetyl-a-D-galactopyranosyl trichloroacetimidate - CAS 86520-63-0
Category:
Carbohydrates
Product Name:
2,3,4,6-Tetra-O-acetyl-a-D-galactopyranosyl trichloroacetimidate
CAS Number:
86520-63-0
Molecular Weight:
492.69
Molecular Formula:
C16H20Cl3NO10
COA:
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MSDS:
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Structure:
Monosaccharides
Chemical Structure
CAS 86520-63-0 2,3,4,6-Tetra-O-acetyl-a-D-galactopyranosyl trichloroacetimidate

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Reference Reading


1.Synthesis of N-acetylglucosamine containing Lewis A and Lewis X building blocks based on N-tetrachlorophthaloyl protection--synthesis of Lewis X pentasaccharide.
Lay L1, Manzoni L, Schmidt RR. Carbohydr Res. 1998 Aug;310(3):157-71.
Phenyl 6-O-benzyl-2-deoxy-2-tetrachlorophthalimido-1-thio-beta-D- glucopyranoside (5a) and thexyldimethylsilyl 6-O-benzyl-2-deoxy-2-tetrachlorophthalimido-beta-D- glucopyranoside (5b) gave with O-(2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl)trichloroacetimida te (8) in the presence of BF3.Et2O as catalyst exclusively lactosamine derivatives 7a and 7b, respectively, in high yields. Ensuing reaction with O-(3, 4-di-O-acetyl-2-O-benzyl-alpha-L-fucopyranosyl) trichloroacetimidate (9) in the presence of TMSOTf as catalyst afforded Le(x) trisaccharide intermediates 10a,b. With fucosyl donor 9 and 5a,b as acceptors in the presence of TMSOTf as catalyst glycosylation either at the 3-O or the 4-O was observed, thus leading to mixtures of disaccharides 11a/12a and 11b/12b, respectively; their reaction with 8 furnished Le(x) trisaccharide intermediates 10a,b and Le(a) trisaccharide intermediates 14a,b. Transformation of 10b into the corresponding trichloroacetimidate 17 and reaction with lactose acceptor 19 in the presence of Zn(OTf)2 as catalyst gave protected Le(x) pentasaccahride intermediate 21, which on deprotection led to unprotected Le(x) pentasaccharide 1.
2.Synthesis of a thio-linked Lewis A (Le(a)) epitope.
Eisele T1, Windmüller R, Schmidt RR. Carbohydr Res. 1998 Jan;306(1-2):81-91.
The synthesis of heptyl (alpha-L-fucopyransoyl)-(1-->4)-S-[(beta-D-galactopyranosyl)-(1--> 3)] -1,4-dithio-beta-D-glucopyranoside (2), as thio-linked Lewis A analogue was based on thexyldimethylsilyl 3-O-allyl-2-O-benzoyl-6-O-(4-methoxybenzyl)-4-thio-beta-D-glucopyranosid e (15) which was readily obtained from D-galactose. Reaction of 15 with O-3,4-di-O-acetyl-2-O-(4-methoxybenzyl)-alpha-L-fucopyranosyl trichloroacetimidate (8) as fucosyl donor afforded the alpha-(1-->4)-thio-linked disaccharide. Replacement of the 4-methoxybenzyl groups by acetyl groups and removal of the 3a-O-allyl group afforded as 3a-O-unprotected acceptor thexyldimethylsilyl (2,3,4-tri-O-acetyl-alpha-L-fucopyranosyl)-(1-->4)-S-6-O-acetyl-2-O-benz oyl -4-thio-beta-D-glucopyranoside (19), which gave with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl trichloroacetimidate as galactosyl donor (20) the trisaccharide. Transformation into a trichloroacetimidate as glycosyl donor, glycosylation of heptylmercaptan, and then removal of the O-acyl protective groups afforded target molecule 2.
3.Synthesis of two phosphate-containing "heptasaccharide" fragments of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B.
Slaghek TM1, Maas AA, Kamerling JP, Vliegenthart JF. Carbohydr Res. 1991 Apr 2;211(1):25-39.
The "heptasaccharides" O-alpha-D-galactopyranosyl-(1----3)- O-alpha-D-glucopyranosyl-(1----3)-alpha, beta-L-rhamnopyranose 2''-[O-alpha-D-galactopyranosyl-(1----3)-O-alpha-D-glucopyranosyl- (1----3)-O-alpha-L-rhamnopyranosyl-(1----3)-D-ribit-5-yl sodium phosphate] (25) and O-alpha-D-galactopyranosyl- (1----3)-O-alpha-D-glucopyranosyl-(1----3)-alpha, beta-L-rhamnopyranose 2''-[O-alpha-D-galactopyranosyl-(1----3)-O-alpha-D-glucopyranosyl- (1----3)-O-alpha-L-rhamnopyranosyl-(1----4)-D-ribit-5-yl sodium phosphate] (27), which are structural elements of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B ([----2)- -alpha-D-Galp-(1----3)-alpha-D-Glcp-(1----3)-alpha-L-Rhap- (1----X)-D-RibOH-(5-P----]n; 6A X = 3, 6B X = 4), respectively, have been synthesized. 2,4-Di-O-acetyl- 3-O-[2,4,6-tri-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D- galactopyranosyl)-alpha-D-glucopyranosyl]-alpha-L-rhamnopyranosyl trichloroacetimidate (13) was coupled with 5-O-allyloxycarbonyl-1,2,4-tri-O- benzyl-D-ribitol (10), using trimethylsilyl triflate as a promotor (----14), and deallyloxycarbonylation (----15) and conversion into the corresponding triethylammonium phosphonate then gave 16.
4.Synthesis of the Sda determinant and two analogous tetrasaccharides.
van Seeventer PB1, Kamerling JP, Vliegenthart JF. Carbohydr Res. 1997 Apr 21;299(3):181-95.
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.