How is 3-Ethyl-2-methyl-5-(4-morpholinylmethyl)-1,5,6,7-tetrahydro-4H-indol-4-one (CAS: 7416-34-4) typically synthesized?

3-Ethyl-2-methyl-5-(4-morpholinylmethyl)-1,5,6,7-tetrahydro-4H-indol-4-one (CAS: 7416-34-4) is typically synthesized through a multi-step process involving the condensation of an appropriate indole derivative with 4-(morpholinomethyl)benzaldehyde. The reaction is catalyzed by a Lewis acid such as aluminum chloride. The yield is around 65%, and the selectivity is high, making the target compound the major product.