Synthesis and properties of some N-pyridoxyl-L-amino acids and N-(5-phosphopyridoxyl)-L-amino acids

Pyridoxal and pyridoxal-5-phosphate have been condensed with l-alanine, l-serine, l-aspartic acid, l-glutamic acid, l-tyrosine, l-tryptophan and l-arginine and the resulting N-pyridoxylidene-amino acids reduced catalytically to the corresponding N-pyridoxyl- and N-(5-phosphopyridoxyl)-l-amino acids. Glutamic acid appears to undergo cyclization to give the pyridoxyl derivative of pyrrolidone carboxylic acid. Reduction of the condensation product between pyridoxal and pyridoxamine results in the formation of pyridoxyl-pyridoxamine (dipyridoxylamine). The paper-chromatographic properties of these substances in two different solvent systems are described.