Synthesis of pseudotrisaccharides related to ribostamycin

The three protected sisamine derivatives 2i, 2j and 3, with a free 5-hydroxyl group, have been synthesized. Glycosylation at the 5 position with various pentofuranose derivatives yielded after deprotection of the 6a approximately i ribostamycin related aminoglycoside. These pseudotrisaccharides showed only low antibacterial activities with respect to the parent compounds.