The inhibition of the b-glucosidases from sweet almonds and Caldocellum saccharolyticum at varying pH values by the glucosamine-related inhibitors 1 ± 7 has been compared to the inhibition by the known glucose analogues 8 ± 14. The amino derivatives 3, 4, 6, and 7 were prepared in one step from the known 15 ± 18 (Scheme 1), and the amino-1,2,3-triazole 5 by a variant of the synthesis leading to the glucose analogue 12 (Scheme 2). The key step for the preparation of the aminoimidazole 1 and of the amino-1,2,4-triazole 2 is the regioselective cleavage of the benzyloxy group at C(2) of the gluconolactam 35 and the mannonolactam 57, respectively, by BCl 3 and Bu 4 NBr (Schemes 3 and 4, resp.). The pH optimum for the inhibition by the amines is lower than their pK HA values, evidencing that they are bound as ammonium salts and that H-bonding between C(2)ÀNH 3 and the cat. base B À contributes more strongly to binding than any possible H-bond to the NH 2 ÀC(2) group. The influence of the ammonium group on the inhibitory strength correlates with the basicity of the glycosidic heteroatom. The strongest increase of the inhibitory strength is observed for the amines lacking a glycosidic heteroatom (DDG(OH 3 NH 3 ) À 1.5 to À 2.9 kcal/mol). The increase is less pronounced for the amino derivatives 3 ± 4, which possess a weakly basic glycosidic heteroatom (DDG(OH 3 NH 3 ) À 0.6 to À 1.1 kcal/mol); the amino compounds 1 and 2, which possess a strongly basic glycosidic heteroatom, are weaker inhibitors than the corresponding hydroxy compounds, as expressed by DDG(OH 3 NH 3 ) between 4.3 and 4.7 kcal/mol for the amino-imidazole 1, and between 2.3 and 2.8 kcal/mol for the amino-1,2,4-triazole 2, denoting the dominant detrimental influence of a C(2)ÀNH 3 group on the H-bond acceptor properties of a sufficiently basic glycosidic heteroatom.