Synthesis of Isocoumarins and their Biological Activities

Abstract

3-(Hydroxyphenyl)-isocoumarins, 3-aminoisocoumarins, 3-acetoxy-4-acetylisocoumarins, 4-carboxy(or carboethoxy)isocoumarins, and other various ring substituted isocoumarins were synthetized through different routes. The constitution of the synthetized compounds was confirmed by IR, NMR and mass spectrometry. Many isocoumarin derivatives so far synthetized showed interesting effects on plants. In particular, isocoumarins having 4-carboxyl- or 4-carboethoxyl group exhibited auxin-like activity on radish and rice plants at low concentrations. Among other isocoumarins, a considerable selectivity in their bioactivity was also observed. In general, radishes were more susceptible than rice and barnyard grass. However some isocoumarins affected more strongly on the rice than the radishes. On the other hand, the isocoumarins with a 3-methyl group showed both plant growth regulating activity and fungicidal activity. Thus, the development of some non-persistent and selective pesticides may be expected in this series.