Synthesis and Structure Activity Relationship Studies of Benzothieno[3,2-b]furan Derivatives as a Novel Class of IKKβ Inhibitors

Abstract

As a novel class of IKKβ inhibitors, a series of tricyclic furan derivatives was designed and synthesized based on the structure of known thiophene IKKβ inhibitors. Among the various fused furan derivatives synthesized, a benzothieno[3,2-b]furan derivative 13a displayed potent inhibitory activity towards IKKβ in enzymatic and cellular assays. The potent inhibitory activity originates from an intramolecular non-bonded S…O interaction which was confirmed by the X-ray structure of JNK3 with 16k. The introduction of further substituents on the core structure led to the discovery of the 6-alkoxy derivatives, which possessed a comparable IKKβ inhibitory activity to 13a and an improved metabolic stability. Among these, appropriately lipophilic compounds 16a, h, i, and 13g (log D>2) were found to possess good oral bioavailability.