New derivatives of 2-carboxychromanone-4 as potential antiinflammatory drugs. I. Cis-and trans-beta-2,4-dihydroxybenzoylacrylic acids and their derivatives.

Proof is presented that the product of the reaction of resorcin and maleic anhydride in the presence of aluminum chloride in ethylene chloride solutions is cis-beta-2,4-dihydroxybenzoylacrylic acid (I). Cis and trans acids (I and II) were isomerized to 2-carboxy-7-hydroxychromanone-4(III). Reactions of acetylation of compounds I, II and III were studied.