How is 3-(Pyridin-2-ylmethylene)indolin-2-one (CAS: 3367-88-2) typically synthesized?

3-(Pyridin-2-ylmethylene)indolin-2-one is typically synthesized via a condensation reaction between indole-2-one and 2-picolylamine. The reaction is catalyzed by Lewis acids such as aluminum chloride. The process involves the formation of an imine intermediate followed by intramolecular cyclization under acidic conditions. The yield is generally around 70-80%, and the reaction is selective for the desired product.