Brain Permeable Tafamidis Amide Analogs For Stabilizing Ttr And Reducing App Cleavage

Tafamidis, 1, a potent transthyretin kinetic stabilizer, weakly inhibits the gamma-secretase enzyme in vitro. We have synthesized four amide derivatives of 1. These compounds reduce production of the A beta peptide in N2a695 cells but do not inhibit the gamma-secretase enzyme in cell-free assays. By performing fluorescence correlation spectroscopy, we have shown that TTR inhibits A beta oligomerization and that addition of tafamidis or its amide derivative does not affect TTR's ability to inhibit A beta oligomerization. The piperazine amide derivative of tafamidis (1a) efficiently penetrates and accumulates in mouse brain and undergoes proteolysis under physiological conditions in mice to produce tafamidis.