Amino Acid-Based Synthesis And Glycosidase Inhibition Of Cyclopropane-Containing Iminosugars

Synthesis of four iminosugars fused to a cyclopropane ring is described using L-serine as the chiral pool. The key steps are large-scale preparation of an alpha,beta-unsaturated piperidinone followed by completely stereoselective sulfur ylide cyclopropanation. Stereochemistry of compounds has been studied by nuclear Overhauser effect spectroscopy (NOESY) experiments and H-1 homonuclear decoupling to measure constant couplings. The activity of these compounds against different glycosidases has been evaluated. Although inhibition activity was low (compound 8a presents a (K-i) of 1.18 mM against beta-galactosidase from Escherichia coli), interestingly, we found that compounds 8a and 8b increase the activity of neuraminidase from Vibrio cholerae up to 100%.