Photosensitized oxidation of maleic acid by singlet oxygen

Feroxidation of maleic acid by peracids like peroxytrifluoroacetic acid and permonosulphuric acid [caro's acid] is well established. Peroxide oxidation of maleic acid gives mainly racemic-tartaric acid by trans-addition while cis-addition to maleic acid leads to the formation of meso-tartaric acid. Maleic acid also gives racemic mixture of alpha, Beta dibromosuccinic acid on bromination whereas fumaric acid yields meso-modification of alpha, Beta dibroraosuccinic acid, A careful survey of the literature reveals that no attention has been paid to the oxidation of maleic acid by singlet oxygen, therefore, the present study was undertaken