How is N-(2,5-Dimethoxyphenyl)-3-oxobutanamide (CAS: 6375-27-5) typically synthesized?

N-(2,5-Dimethoxyphenyl)-3-oxobutanamide (CAS: 6375-27-5) is typically synthesized via the condensation of 2,5-dimethoxybenzaldehyde with acetamide in the presence of a suitable catalyst such as p-toluenesulfonic acid (p-TSA). The reaction involves the formation of an intermediate imine, which is then cyclized to form the desired amide. The yield is generally high, and the reaction is selective under mild conditions.