Synthesis of new pseudodisaccharide aminoglycoside antibiotics from carbohydrates

Novel pseudodisaccharide-type aminocyclitol antibiotic models, built up from D-arabinose, D-ribose, D-glucosamine, L-ristosamine and L-acosamine 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 extends the scope of the Ferrier reaction, by demonstrating that acid-labile 2-deoxydisaccharides can also be readily transformed into the corresponding pseudodisaccharides under the slightly acidic conditions of this ring-transformation.