EFFECT OF SOLVENT ON PHOTOLYSIS OF ALPHA-LIPOIC ACID

The photolysis of α-lipoic acid in different solvents was followed by tic and uv. It was found that a number of products are formed in each solution and the number and kind of product are dependent on the solvent. The chain length is determined by the kind of solvent; the length of the polymer chain decreased with increased availability of hydrogen atoms in the solvent. The amounts of products as well as the rate of formation of products are also solvent dependent. A mechanism is postulated in which the disulfide bond is broken homolytically in the first step. It is postulated that the reaction proceeds by chain transfer of hydrogen atoms from the solvent, causing short chains; by attack of the radicals on the other lipoic acid molecules, forming chains of longer length; or by the hydrolysis of the thio ketone formed by intramolecular abstraction of the tertiary hydrogen. © 1969, American Chemical Society. All rights reserved.