SYNTHESIS OF NEW PSEUDODISACCHARIDE AMINOGLYCOSIDE ANTIBIOTICS FROM CARBOHYDRATES

Novel pseudodisaccharide-type aminocyclitol antibiotic models, built u p from D-arabinose, D-ribose, D-glucosamine, L-ristosamine and L-acosa mine have been synthesized by the glycosylation of suitably protected (azido)deoxyinosose aglycones derived by the Ferrier carbocyclic ring transformation of carbohydrate precursors. An alternative approach to related pseudodisaccharides, based on the Ferrier carbocyclization of reducing disaccharides, has also been elaborated. This latter method e xtends the scope of the Ferrier reaction, by demonstrating that acid-l abile 2-deoxy-disaccharides can also be readily transformed into the c orresponding pseudodisaacharides under the slightly acidic conditions of this ring-transformation.