SYNTHESIS AND CHARACTERIZATION OF FLUORESCENT PRODUCTS DERIVED FROM MALONALDEHYDE AND AMINO ACIDS

Amino acids or their esters and n-hexy lamine react with malonaldehyde to yield conjugated Schiff bases. The Schiff bases possess characteristic absorption in the ultraviolet and visible regions. In solutions, Schiff bases derived from amino acids show spectral shifts on standing at room temperature, and isosbestic points are found at 401-404 mμ. cis-trans isomerization about the C═C bond or C═N bond may account for the observed spectral shift. The electronic absorption and fluorescence properties have been attributed to the chromophoric system NC═CC═N which contains six π electrons. Infrared spectra contain a band in the 1650-cm-1 region indicating the presence of a C═N bond. Mass spectral analyses are carried out after the Schiff bases are reduced with sodium borohydride to confirm that 1 mole of malonaldehyde reacts with 2 moles of amino acid ester or n-hexylamine to yield N′,N′-disubstituted 1-amino-3-iminopropenes. © 1969, American Chemical Society. All rights reserved.