Synthesis of 4-nitrophenyl β-D-fucofuranoside and β-D-fucofuranosyl-(1 → 3)-D-mannopyranose: Modified substrates for studies on catalytic requirements of β-D-galactofuranosidase
Syntheses of 4-nitrophenyl β-D-fucofuranoside (6) and β-D- fucofuranosyl-(1 → 3)-D-mannopyranose (10) are reported. These compounds, as analogues of galactofuranosides, were used for studying the influence of the hydroxyl group at C-6 in the interaction of the substrate with β-D- galactofuranosidase...
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| Autores principales: | , , |
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| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00086215_v323_n1-4_p7_Chiocconi |
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| Sumario: | Syntheses of 4-nitrophenyl β-D-fucofuranoside (6) and β-D- fucofuranosyl-(1 → 3)-D-mannopyranose (10) are reported. These compounds, as analogues of galactofuranosides, were used for studying the influence of the hydroxyl group at C-6 in the interaction of the substrate with β-D- galactofuranosidase. For the synthesis of the fucofuranosides, 2,3,5-tri-O- benzoyl-6-bromo-6-deoxy-D-galactono-1,4-lactone (1) was the key intermediate, which upon reduction of the lactone group with diisoamylborane, acetylation of the anomeric hydroxyl group, and catalytic hydrogenolysis of the bromine at C-6, led to 1-O-acetyl-2,3,5-tri-O-benzoyl-α,β-D-fucofuranose (4), a convenient derivative for the preparation of fucofuranosides. Compound 4 was glycosylated in the presence of SnCl4, either with 4-nitrophenol for the preparation of 6, or with 2,5,6-tri-O-benzoyl-D-mannono-1,4-lactone (7), for the synthesis of disaccharide 10, via the glycosyl-aldonolactone approach. The synthetic route developed for the β-D-fucofuranosides is simple and efficient. Compound 6 was not hydrolyzed by incubation with the exo β-D- galactofuranosidase from Penicillium fellutanum, showing that HO-6 is essential for interaction of the substrate with the enzyme. (C) 2000 Elsevier Science Ltd. |
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