Abstract The proposed 6-and 7-methyl-1, 2-benzisoxazole-3-acetic acids (3) have been shown to be 6-and 7-methyl-4-hydroxyimino-2-oxo-chromans. The method of preparation of these unknown acids was demonstrated by the synthesis of 1, 2-benzisoxazole-3-acetic acid, starting from 3-methyl-1, 2-benzisoxazole. Comparative results of the auxin test are reported.