| Abstract: | Homophthalic acid (I) reacts with acetic anhydride in the presence of base to form the expected product, o-carboxyphenylacetone (III). Besides III, three other new products were formed, namely, 3-methyl-4-carboxyisocoumarin (II), 4-acetyl-3-methylisocoumarin (IV) and 8-acetyl-7-methylnaphtho1,2-c]isocoumarin. A mechanism for the formation of these compounds is presented. The presence of 3-methyl-4-carboxyisocoumarin (II) supports an earlier suggestion (1) that acylation can occur prior to and without decarboxylation, which has been a point of concern in this reaction. |
