A series of alkylamido- (1) and alkylaminobiphenyl (2) derivatives were synthesized as possible bioisosters of the reported ACAT inhibitors phenylpyridazine analogues (I). Both 1 and 2 were tested on the human ACAT-1 and ACAT-2 isoforms. The amino derivatives 2 were found to be inactive, contrary to the related pyridazine derivatives. By contrast, the ortho-substituted amides 1a and 1d showed an interesting activity. These results support the essential role of the pyridazine nucleus. Modeling studies were also performed.
