The synthesis of mercaptoquinolonecarboxylic acids from rhodanine-oxindoles

The preparation of mercaptoquinolonecarboxylic acids from rhodanine-oxindoles has been studied. As a result, five new mercapto acids were synthesized; four of these, namely, the methyl-mercaptoquinolonecarboxylic acids, represent a type not previously recorded in the chemical literature. The mechanism of the alkaline hydrolysis of rhodanine-oxindoles has been investigated and the structure established for the salts formed