A new class of low molecular weight, highly potent and selective non peptidic inhibitors of aminopeptidase N (APN/CD13) is described. We report the synthesis and in vitro evaluation of racemic substituted analogues of 7-amino-benzocyclohepten-6-one 1a. We investigated various substitutions on the aromatic ring with phenyl and halogen groups. In vitro kinetic studies revealed that these compounds are among the most effective APN/CD13 inhibitors ...