Three tetrahydropyridoimidazole-type glycosidase inhibitors have been synthesized with the 3-deoxy ribo-and arabino-, and 3-deoxy-3-fluoro gluco-configurations and two of them screened for activity against alpha- and beta-gluco-and mannosidase enzymes. Only one substance, the 3-deoxy-3-fluoro-derivative of the gluco-configured tetrahydropyridoimidazole was found to have any activity against a single enzyme, sweet almond beta-glucosidase, and even then at a level 100-fold lower than that of the corresponding simple gluco-configured tetrahydropyridoimidazole thereby underlining the importance of the 3-hydroxy group in the key substrate-enzyme interactions. (c) 2013 Elsevier Ltd. All rights reserved.