A series of seven-membered iminosugars bearing an acetamido group beta- or gamma- to the endocyclic nitrogen have been synthesized via simple transformations of previously described polysubstituted azepanes. These tetra- and trihydroxylated acetamido azepanes are ring homologues of 2-acetamido-1,2-dideoxy-glyconojirimycins and 2-acetamido-1-N-iminosugars respectively. Screening of these azepanes towards a range of commercially available glycosidases demonstrated their potential as selective and potent hexosaminidase inhibitors with K-i's in the submicromolar range. A correlation between the relative configuration of the azepanes and their ability to inactivate hexosaminidases was also observed for the first time for this class of compounds with one notable exception for the most potent compound. (C) 2009 Elsevier Ltd. All rights reserved.