Synthesis of novel heterobranched beta-cyclodextrins having beta-D-N-acetylglucosaminyl-maltotriose on the side chain

From a mixture of N-acetylglucosaminyl-beta-cyclodextrin (GlcNAc-betaCD) and lactose, beta-D-galactosyl-GlcNAc-betaCD (Gal-GlcNAc-betaCD) was synthesized by the transfer action of beta-galactosidase. GlcNAc-maltotriose (Glc3) and Gal-GlcNAc-Glc3 were produced with hydrolysis of GlcNAc-betaCD by cyclodextrin glycosyltransferase, and Gal-GlcNAc-betaCD by bacterial saccharifying alpha-amylase respectively. Finally, GlcNAc-Glc3-betaCD and Gal-GlcNAc-Glc3-betaCD were synthesized in 5.2% and 3.5% yield when Klebsiella pneumoniae pullulanase was incubated with the mixture of GlcNAc-Glc(3) and betaCD, or Gal-GlcNAc-Glc3 and betaCD respectively. The structures of GlcNAc-Glc3-betaCD and Gal-GlcNAc-Glc3-betaCD were analyzed by FAB-MS and NMR spectroscopy and identified as 6-O-alpha-(6(3)-O-beta-D-N-acetylglucosaminyl-maltotriosyl)-betaCD, and 6-O-alpha-(4-O-beta-D-galactopyranosyl-6(3)-O-beta-D-N-acetylglucosaminyl-maltotriosyl)-betaCD respectively.