How is Aripiprazole Impurity 1 (CAS: 120004-79-7) typically synthesized?

Aripiprazole Impurity 1 is typically synthesized through a series of steps involving reactions such as amide formation, reduction, and cyclization. Catalysts like palladium and bases like potassium carbonate are often used. The synthesis involves multiple steps and requires careful temperature control to ensure selectivity and yield, typically around 80-90%. Detailed reaction conditions and purification methods are essential for obtaining high-purity impurity samples.