The Effect of 4-Hydroxyl Substituent on the Singlet Chemiexcitation Yield in Base-catalyzed Air Oxidation of 3,5-Dichlorophenylpyruvic Acids

Abstract

Abstract 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 is made on the difference in spin state selectivity between 1 and 2 or 3.