Synthesis, characterization and phytotoxic activity of hydroxylated isobenzofuran-1(3H)-ones

Two hydroxylated isobenzofuranones 3 and 4 were synthesized from benzoic acids. The compounds were fully characterized by IR, NMR (1H and 13C), HRMS, and X-ray crystallography. Compounds 3 and 4 crystallized in the space group Pc and P21/n, respectively. DFT calculations were used to confirm undoubtedly their NMR chemical shifts. Biological assays showed that these compounds are capable of interfering with the radicle growth of monocotyledonous and dicotyledonous species, whereas the photosynthetic electron transport chain was substantially unaffected.