6-Hydroxychroman-2-carboxylic acids: Novel antioxidants

6-Hydroxychroman-2-carboxylic acids (I) have been found to be effective antioxidants in animal fats, vegetable oils, and emulsion systems. Two new Open image in new window syntheses of these compounds have been developed. Structure-activity correlations for I with various substitutents at C2, C5, C7, and C8 in various test systems have been obtained. In addition, the homologous chroman acetic acids, which are also antioxidants, and a number of other derived compounds have been synthesized. The most effective antioxidant in this series is the tetramethyl compound I (R2=R5=R7=R8=CH3). This compound has activity which compares well with the better commercial antioxidants.