MODIFICATION OF CYCLODEXTRINS BY INSERTION OF A HETEROGENEOUS SUGAR UNIT INTO THEIR SKELETONS - SYNTHESIS OF 2-AMINO-2-DEOXY-BETA-CYCLODEXTRIN FROM ALPHA-CYCLODEXTRIN

Acetolysis of fully acetylated alpha-cyclodextrin 5a resulted in restr icted fission of only one of the glycosidic bonds to give the acyclic maltohexaose peracetate 6a in 46% yield. Regioselective modifications of both terminals of hexasaccharide 6a were performed by employing Lew is acid-catalysed thioglycosidation and O-benzylidenation followed by its reductive cleavage as the key reactions, to give the partially O-b enzylated maltohexaoside 9a with the sole hydroxy group at the 4(VI)-p osition. Coupling of compound 9a and a D-glucosamine precursor by the trichloroacetimidate method gave the heptasaccharide 15. subsequent de protection of which gave 2-amino-2-deoxy-beta-cyclodextrin 1.