Aromatic Amines in Organic Synthesis. Part II. p-Aminocinnamaldehydes

Ten derivatives of p-aminocinnamic aldehydes were prepared from the reaction of either aromatic amines with dimethylaminoacrolein or benzaldehydes with acetaldehyde. Their chemical structure and purity were verified by ¹H NMR, ¹³C NMR and IR spectroscopic methods. We found that the synthesis applying dimethylaminoacrolein as the reagent gets better yields than the one based on the reaction with acetaldehyde. The yields of the cinnamic aldehydes varied according to the type of the amino group and the number and position of the substituents. The basic spectroscopic properties of the p-aminocinnamic aldehydes are also described since the compounds may be a precursor for the synthesis of dyes for diverse applications, e.g., in medicine and optoelectronics.