Structure-activity relationships in aminocyclopentitol glycosidase inhibitors.

Aminocyclopentitol analogs of beta-D-glucose, beta-D-galactose and alpha-D-galactose bearing alkyl substituents as aglycon mimics on the amine function were prepared and tested for inhibition of various glycosidases. N-benzyl-beta-D-gluco derivatives 1-4 and N-benzyl-beta-D-galacto derivative 5 inhibited beta-galactosidase and beta-glucosidase. N-benzyl-alpha-D-galacto aminocyclopentitol 6 strongly inhibited alpha-galactosidase. The inhibitory activities observed were generally stronger compared to those of their primary amine analogs. A structure-activity relationship analysis was carried out including data from thirty-five different aminocyclopentitol glycosidase inhibitors. The strongest inhibitions reported for any enzyme were associated with a perfect stereochemical match between aminocyclopentitol and glycosidase, including the alpha- or beta-configuration of the amino-group corresponding to the enzyme's anomeric selectivity.