Identification of a decarboxylation product of retinoic acid

The oxidative decarboxylation of retinoic acid was investigated utilizing a model system concisting of all-trans-retinoic acid, H₂O₂ and horseradish peroxidase. The decarboxylation products were purified by high-performance liquid chromatography on bonded, octadecylsilane columns. Based on mass spectral, nuclear magnetic resonance, ultraviolet and Fourier transform infrared analyses, the major decarboxylation product was identified as a 4-oxo-C₁₉ aldehyde with a hyrdoxyl group on the side chain at C₉, specifically 8-(2,6,6,-trimethyl-3-oxocyclohex-1-enyl)2,6-dimethyl-6-hydroxyoctatrienal.