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The aniline derivative 3 is a key building block of rilpivirine (TMC278) 2, a new potent NNRTI compound under clinical evaluation. In this paper we describe the development of a new synthesis of 3 based on a Heck coupling between a halogenated aniline and acrylonitrile using low loading of Pd/C (0.5 mol %) as catalyst. This resulted in a process which has been successfully transferred into production on 2400 mol-scale (6000 L reactor)

The stepwise optimization towards a safe, reproducible, and high-yielding oxidation of azepine 2 into the prochiral nitrone 4 is described, with emphasis on the elimination of Davis reagent 3. m-Chloroperoxybenzoic acid (mCPBA) was found to be an elegant and scalable alternative oxidant regarding safety, yield, and easy workup procedures. Nitrone 4 was obtained in 95% yield and used without purification or isolation in the cycloaddition step to provide oxazolidone 6 in high yield. The process was scaled up successfully to an 800-L scale (60 mol of starting material).