A NEW SYNTHESIS OF 5-AMINOLEVULINIC ACID VIA DYE-SENSITIZED OXYGENATION OF N-FURFURYLPHTHALIMIDE

Dye-sensitized oxygenation of N-furfurylphthalimide using Rose Bengal, fullerene-C-60, and coronene as sensitizers yielded 5-phthalimido-4-o xopentenoic acid. The acid was then hydrogenated with palladium-on-car bon, and was hydrolyzed to finally produce 5-aminolevulinic acid (1) a t about 50% total yield. The oxygenation process was studied in relati on to the mechanistic process and the improvement of yield, using seve ral solvent systems and 2,3-dimethyl-2-butene, and was explained as a singlet oxygen reaction. The synthesis method used for 1 was an improv ement on previously reported methods with respect to: the total yield, the commercial availability of the starting materials, and the econom ical nature of the oxygenation process, even on a large scale.