Chemical Modification of Kanamycin A. II. Nucleophilic Displacement Reactions of Kanamycin-A-4''-sulfonates
Titel:
Chemical Modification of Kanamycin A. II. Nucleophilic Displacement Reactions of Kanamycin-A-4''-sulfonates
Auteur:
Albert, R. Dax, K. Stutz, A. E. Weidmann, H.
Verschenen in:
Journal of carbohydrate chemistry
Paginering:
Jaargang 1 (1982) nr. 3 pagina's 289-299
Jaar:
1982-01-01
Inhoud:
Reactions of 2',3',4',2'',6''-penta-O-acetyl-tetra-N-tert-butyloxycarbonyl-kanamycin-A-4''-brosylate (4b) or-4''-triflate (4c) with acetate, thiolacetate, azide, and fluoride, respectively, result in the formation of the corresponding derivatives of 4''-epi-kanamycin A (5a-d). While 4b invariably forms an elimination byproduct (9), the only side—reaction of 4c consists in a neighboring group attack with formation of a 3''-epi-4''-cyclic urethane (7). Removal of the protecting groups yields 4''-epi-(6a), 4''-thio-4''-epi-(6b), 4''-deoxy-4''-fluoro-4''-epi-(6d), 4''-azido-4''-deoxy-4''-epi-(6c), and after hydrogenation of the latter, 4''-amino-4''-deoxy-4''-epi-kanamycin A (6f). Methyl 2,6-di-O-acetyl-3-amino-3-N-tert-butyloxycarbonyl-3-deoxy-4-O-triflyl-β-D-glucopyranoside (1b) served as a model to anticipate preparation, handling, and reactivity of 4c.