SYNTHESIS AND EVALUATION OF HOMOAZASUGARS AS GLYCOSIDASE INHIBITORS

In an effort to develop transition-state mimetics of the glycosidase-catalyzed reaction, five- and six-membered azasugars and their home-analogs were prepared and tested as inhibitors of glycosidases. Inhibition studies indicate that the fucosyl cationlike, five-membered imine 1 and its reduced form 2 are potent inhibitors of alpha-fucosidase from bovine kidney with respective K-i values of 160 nM and 2 mu M. The five-membered homoaminoazasugar 3 is also a potent inhibitor of the enzyme (K-i = 1.9 x 10(-6) M), while the glucose and mannose-like six-membered homoaminoazasugars 4 and 5 are less potent than the corresponding 1-deoxyazasugars as inhibitors of alpha-glucosidase and alpha-mannosidase, respectively. The primary amino group was placed in an attempt to introduce additional electrostatic interactions in the active site. The inhibitory activities are, however, in the high mu M range. Synthesis of homoazasugars structurally related to a disaccharide and a nucleoside is also described.