Oligosaccharides Related to Tumor-Associated Antigens. Part I. Synthesis of the propyl glycoside of the trisaccharide α-L-Fucp-(1 → 2)-β-D-Galp-(1 → 3)-β-D-GalpNAc, component of a tumor antigen recognized by the antibody MBr1

✍ Scribed by Luigi Lay; Francesco Nicotra; Luigi Panza; Giovanni Russo; Elena Adobati

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: German
• Weight: 419 KB
• Volume: 77
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19940770211

✦ Synopsis

The synthesis of the trisaccharide c ! -L-Fuc~-( 1 +2)-p-o-Ga1pp-( 1 +3)-P-~-GalpNAc-l-OPr (2) is described. The N-acetylgalactosamine 6 was obtained from 4 by an intramolecular displacement of a (trifluo-romethy1)sulfonyloxy by a pivaloyloxy group with its concomitant migration from position 3 to position 4 (Scheme I). The galactosyl donor 9 was obtained from 7 uiu 8 by regioselective opening of the orthoester function with AcOH/pyridine followed by treatment with CC1;CN and 1,8-diazabicyclo[5.4.O]undec-7-ene (DBU) (Scheme 2). Glycosylation of 6 with 9 in the presence of BF;.OEt, gave the disaccharide 10. Selective deprotection of 10 at 0 -C(2') followed by glycosylation with 12 and by standard deprotection afforded the title trisaccharide 2 (Scheme 3 ) . Preliminary biological testing showed that 2 is able to inhibit the binding of the monoclonal antibody MBrl to the target tumor celles MCF7 in a dose-dependent manner.

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Inversion at position 4 was also achieved in disaccharide ~-o-Galp-(l-t3)-~-GlcpNAc