QUANTUM YIELDS IN THE PHOTOCHEMICALLY INDUCED RADICAL CHEMISTRY OF ACYL DERIVATIVES OF THIOHYDROXAMIC ACIDS

Acyl derivatives of N-hydroxyquinazoline-4-thiones are a novel source of disciplined carbon radicals. Quantum yield determination reveals that photolysis of these compounds initiates radical chains, resulting in quantum yields up to PHI = 60. Comparative studies with acyl derivatives of N-hydroxy-2-thiopyridone show that the quinazoline derivatives are more light-sensitive than the thiopyridone compounds. The carbon radicals thus formed from the former can be trapped selectively, without the formation of rearranged products (i.e. without the competition of the radicophilic thiocarbonyl group of the starting material with the radical trap).