Microwave dielectric heating proved to be an efficient method for the one-pot and stepwise syntheses of symmetrical and unsymmetrical naphthalenediimide derivatives of alpha-amino acids. Acid-labile side chain protecting groups are stable under the reaction conditions; protection of the alpha-carboxylic group is not required. The stepwise condensation of different amino acids resulted in high yields of unsymmetrical naphthalenediimides. The reaction proceeds without racemization and is essentially quantitative.
Pengo, P., Pantos, G. D., Otto, S., & Sanders, J. K. M. (2006). Efficient and mild microwave-assisted stepwise functionalization of naphthalenediimide with alpha-amino acids. Journal of Organic Chemistry, 71(18), 7063-7066. https://doi.org/10.1021/jo061195h