Benzoylation of D-galactono-1,4-lactone with 2.2 mol of benzoyl chloride, at −23°, gave the 2,6-dibenzoate (2, 62%). Tin(IV) chloride-catalyzed glycosylation of 2 with 1,2,3,5,6-penta-O-benzoyl-α,β-D-galactofuranose (1) afforded 2,6-di-O-benzoyl-5-O-(2,3,5,6-tetra-O-benzoyl-β-D-galactofuranosyl)-D-galactono-1,4-lactone (4, 70%), HO-3 of which was benzoylated to give 5. The structure of 4 was confirmed by its conversion into crystalline β-D-Galf-(1→5)-D-Gal-ol (8). Reduction of the lactone function of 5 with di-isoamylborane followed by debenzoylation gave β-D-Galf-(1→5)-D-Galf (7). A by-product of the condensation of 1 with 2 was characterized as 2,6-di-O-benzoyl-3,5-di-O-(2,3,5,6-tetra-O-benzoyl-β-D-galactofuranosyl)-D-galactono-1,4-lactone (9), which was converted, as for 5, into β-D-Galf-(1→3)[β-D-Galf-(1→5)]-D-Galf (13).
Publication DOI: 10.1016/0008-6215(90)84193-XJournal NLM ID: 0043535Publisher: Elsevier
Institutions: Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
Methods: 13C NMR, 1H NMR, TLC
Found