Synthesis and Biological Assessment of Racemic Benzochromenopyrimidinimines as Antioxidant, Cholinesterase, and A beta(1-42) Aggregation Inhibitors for Alzheimer's Disease Therapy

Given the complex nature of Alzheimer's disease (AD), compounds that are able to simultaneously address two or more AD-associated targets show greater promise for development into drugs for AD therapy. Herein we report an efficient two-step synthesis and biological evaluation of new racemic benzochromene derivatives as antioxidants, inhibitors of cholinesterase and beta-amyloid (A beta(1-42)) aggregation. Based on the results of the primary screening, we identified 15-(3-methoxyphenyl)-9,11,12,15-tetrahydro-10H,14H-benzo[5,6]chromeno [2,3-d]pyrido[1,2-a]pyrimidin-14-imine (3e) and 16-(3-methoxyphenyl)-9,10,11,12,13,16-hexahydro-15H-benzo[5',6']chrome no[2',3':4,5]pyrimido[1,2-a]azepin-15-imine (3 f) as new potential multitarget-directed ligands for AD therapy. Further indepth biological analysis showed that compound 3 f is a good human acetylcholinesterase inhibitor [IC50=(0.36 +/- 0.02) mu m], has strong antioxidant activity (3.61 mu mol Trolox equivalents), and moderate A beta(1-42) antiaggregating power (40.3%).