Practical and Efficient Approach to Scalable Synthesis of Rucaparib

A scalable synthesis of rucaparib was developed from methyl 5-fluoro-2-methyl-3-nitrobenzoate and 4-cyanobenzaldehyde. Methyl 5-fluoro-2-methyl-3-nitrobenzoate was converted into a 2-aminocinnamonitrile derivative, which was subjected to the imino-Stetter reaction with 4-cyanobenzaldehyde to yield trisubstituted indole-3-acetonitrile. The reduction of both nitriles, followed by azepinone scaffold construction and selective monomethylation, completed the synthesis of rucaparib. This synthetic route features the use of inexpensive starting materials, scalability, and ease of purification through recrystallization.