Crystalline derivatives of the following l-amino acids modified by 3,5-dinitro-4-pyridone have been prepared: glycine, alanine, valine, leucine, isoleucine, phenylalanine, serine, threonine, tyrosine, aspartic acid, asparagine, glutamic acid, glutamine, tryptophan, histidine, arginine, methionine and lysine. The modified l-amino acids (DNPY-l-amino acids) could be purified by recrystallization and were characterized by 1H-NMR, IR and UV spectral data. The molar rotation of the DNPY-l-amino acids varied from 2 to 100 times those of the parent amino acids. The effectiveness of 3,5-dinitro-1-(4-nitrophenyl)-4-pyridone as an amino-protecting reagent of l-amino acids is described.

Von den wie angegeben dargestellten Reagentien (IV) ist (IVb) am besten für die Bildung von Derivaten (VI) von verschiedenen Aminosäuren (V) geeignet.