In base-catalyzed air oxidation of substituted phenylpyruvic acids, an excited singlet product is generated from 3, 5-dichloro-4-hydroxyphenylpyruvic acid (1) but excited triplet products from 3, 5-dichlorophenyl-(2) and 3, 5-dichloro-4-methoxyphenylpyruvic acid (3). According to the reaction scheme proposed, the singlet chemiexcitation yield from 1 and the triplet yields from 2 and 3 are 1· 2× 10− 4, 8.3× 10− 4, and 6.7× 10− 4, respectively. A discussion ...
