Synthesis, Mass Spectrometric Studies, and Biological Evaluation of 3,5-Dimethoxyhomophthalic Acid and Related Compounds

3,5-Dimethoxyhomophthalic acid was synthesized in four steps from 3,5-dimethoxycinnamic acid via a series of reactions including cyclization of 3-(3′,5′-dimethoxyphenyl) propionic acid to 5,7-dimethoxy-1-indanone and oxidative decomposition of methyl-2-hydroxy-2-[5, 7-dimethyoxy-1-oxo-1H-inden-2 (3H)-ylidene] acetate to 3,5-dimethoxyhomophthalic acid. The synthesized compounds were characterized by elemental analysis, IR, 1H NMR, and MS. The biological evaluation experiments of 3,5-dimthoxyhomophthalic acid and the related synthesized compounds were also carried out. Naturally occurring biologically active isocoumarins were prepared in a single step by the condensation of the homophthalic acid with appropriate acid chlorides.