Synthesis of tri- and tetrasaccharide haptens related to the Asialo forms of the gangliosides G_M2 and G_M1

Abstract

SUBRAMANIAM SABESAN and RAYMOND U. LEMIEUX. Can. J. Chem. 62, 644 (1984) Synthesis of PDG~INA~(I+~)PDG~~(~+~)PDG~C-O(CH~)~COOCH, (21) and PDGal(l+3)PDGalNAc(1+4)P~Gal-(~+~)PDG~C-O(CH~)~COOCH~ (33) are presented starting from PDG~I(~+~)PDG~c-O(CH~)~COOCH, (1) and ~-galactose. Improvements in the preparations of D-galactal triacetate (7) and tri-O-acetyl-2-azido-2-deoxy-a-~-galactopyranosyl bromide (11) are reported. The syntheses proceeded by way of the tri-0-acetyl-2-deoxy-2-phthalimido-P-D-galactopyranosyl and 4,6-di-0-acetyl-3-0-(tetra-O-acetyl-~~-galactopyranosyl)-2-deoxy-2-phthalimido--~-galactopyranosy bromides (18 and 30), which, in turn, were prepared from the corresponding ally1 glycosides (15 and 23). The I3C chemical shifts for the tri-and tetrasaccharide portions of 21 and 33 are assigned from the chemical shifts that were observed for the carbon atoms in the disaccharides which make up these structures. The trisaccharide (21) On rapporte des amtliorations aux prtparations du triacetate de D-galactal (7) et du bromure de tri-0-acttyl azido-2 dtoxy-2 cr-D-galactopyrannosyle. Les synthkses impliquent la prtparation des bromures de tri-0-acetyl dtoxy-2 phthalimido-2 P-D-galactopyrannosyle et de di-0-acttyl-4,6 0-(tttra-0-acttyl P-D-galactopyrannosy1)-3 dtoxy-2 phthalimido-2 P-~-galactopyrannosyle (18 et 30) qui sont eux-m&mes prtparts h partir des glycosides allyliques correspondants (15 et 23). On a attribut les dtplacements chimiques du "C des portibns tri-et tttrasaccharidiques des composts 21 et 33 en se basant sur les dtplacements chimiques observts pour les atomes de carbones des disaccharides qui composent ces structures. Le trisaccharide (21) n'inhibe que trks faiblement ]'agglutination des cellules rouges A humaines par la lectine de Dolichos biflorus. Le tttrasaccharide 33 est inactif.[Traduit par le journal]

A Convenient Synthesis of Type IV Glycosyl Donors from Type I Disaccharides

“…An analytical sample was prepared by crystallization from ethyl acetate-isopropanol-hexane; mp149-153 °C, Anal. CakxJ f o r C 3 (4). A solution of 3 (3.0g, 3.91 mmol) and sodium cyanoborohydride (1.5 g, 23.87 mmol) in dry tetrahydrofuran (30mL) containing 3A molecular sieves and a crystal of methyl orange was cooled at 0°C.…”

“…The previous synthesis reported in the-literature involved the use of the relatively expensive 2-azido-2-deoxy galactose derivatives for the construction of the B-DGal(1-3) B-D-GalNAc sequence. 3 ' 4 In recent years, use of inflates and mesylates as leaving groups in carbohydrate synthesis has opened new domains. ** Hindsgaul etal.…”

The synthesis of derivatives of lactosamine and cellobiosamine to serve as probes in studies of the combining site of the monoclonal anti-I Ma antibody

“…This was accomplished in a manner very similar to that used to prepare 2 (1). The crude product (29) from the azidonitration (6) of hexa-0-AcO w"'@ acetyl-D-cellobial was treated with N,N-dimethylbromoforminium bromide (Vilsmeier reagent) (1 1) to convert any 1 -acetamido-2-azido-1,2-dideoxy derivative (6) to the acetylated 2-azidoglycosyl bromide (30) and then directly with lithium bromide to convert the 2-azido-1 -nitrates to form the major amount of the bromide (30) (12). The yield of the crystalline product was 32% from the hexa-0-acetyl-D-cellobial.…”

“…The mixture was stirred at room temperature for 3 h to result in a clear red solution before lithium bromide (50 g, 0.57 mol) was added (12). The suspension was stirred for 7 h. The mixture was then diluted with dichloromethane (60 mL) and the supernatant was decanted onto ice (500 g).…”

A facile synthesis of the GalNAcβ1→4Gal target sequence of respiratory pathogens

“…While we previously showed the synthesis and evaluation of multivalent versions of the sequence, 2 which resulted in a multivalent inhibition enhancement, the synthesis of the disaccharide in a form ready for conjugation had to be improved. The disaccharide synthesis has been achieved in 1984 by Lemieux et al 3 but required many steps and consequently had a low overall yield. Since then, the synthesis of the GalNAcb1!4Gal sequence was reported several times.…”