Multicomponent synthesis of dihydrobenzoxazepinones, bearing four diversity points, as potential α-helix mimics

A very short convergent synthesis of dihydrobenzoxazepinones, bearing four diverse diversity points, based on coupling the Ugi reaction with a Mitsunobu cyclization, was developed. These compounds are potential α-helix mimics, where three of the four appendages are expected to imitate the residues in i, i + 4 and i + 7 positions. A library of 22 compounds bearing lipophilic substituents, designed to interact with the hydrophobic cleft of anti-apoptotic protein Bcl-xL, was synthesized. Preliminary biochemical tests, based on competitive binding, have already been carried out.