Design and synthesis of 1,4-dihydropyridine derivatives as BACE-1 inhibitors

BACE-1 has been shown to be an attractive therapeutic target in Alzheimer's disease (AD). Using a 1,4-dihydropyridine (DHP) scaffold, we synthesized new inhibitors of BACE-1 by modifying the known BACE inhibitor 2 containing a hydroxyethylamine (HEA) motif. Using structure-based drug design based on computer-aided molecular docking, the isophthalamide ring of 2 was replaced with a 1,4-dihydropyridine ring as a brain-targeting strategy. Several of the new dihydropyridine derivatives were synthesized and their BACE-1-inhibitory activities were evaluated using a cell-based, reporter gene assay system that measures the cleavage of Alkaline Phosphatase (AP)-APP fusion protein by BACE-1. Most of the 1,4-DHP analogs showed BACE-1-inhibitory activities with IC50 values in the range 8-30 microM, suggesting that the 1,4-DHP skeleton may be utilized to develop brain-targeting BACE-1 inhibitors.