Synthesis of 4H-1,4-oxazines as transthyretin amyloid fibril inhibitors.

4H-1,4-oxazines were designed as transthyretin (TTR) amyloid fibril inhibitors based on an analysis of the interactions between known small molecule inhibitors and TTR by molecular docking. A series of 2,4,6-triaryl-4H-1,4-oxazines was synthesized by the cyclization of N,N-bis(phenacyl)anilines with POCl3 in pyridine. Inhibition of TTR amyloid fibril was evaluated by a fibril formation assay. The results indicate that 4H-1,4-oxazines significantly inhibit TTR amyloid fibril at a concentration of 7.2 μM.