Synthetic Studies on Tumor-Associated Antigens: Efficient Syntheses of Lea and Sialyl-Lea Oligosaccharides,and Their Deaminated Analogs1 |
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Authors: | Yataka Makimura Hideharu Ishida Makoto Kiso Akira Hasegawa |
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Affiliation: | Department of Applied Bioorganic Chemistry , Gifu University , Gifu 501-11, Japan |
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Abstract: | ABSTRACT Efficient syntheses of tumor-associated Lea, sialyl Lea and their deaminated analogs are described. The suitably protected D-glucosamine (4) or D-glucose (5) derivative was successively coupled with the methyl-1-thioglycosides (glycosyl donors) of D-galactose (6) and L-fucose (11) in high yields by using N-iodosuccinimide/trifluoromethanesulfonic acid (NIS/TfOH) as the glycosyl promoter. The resulting trisaccharides (12 and 13) were each converted, by deprotections, to the Lea determinant (17) and its deaminated analog (18), and by further glycosylation with the phenyl-2-thioglycoside of N-acetylneuraminic acid (25), to the sialyl-Lea determinant (30) and its deaminated analog (31), respectively. |
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