Toxicity of coumarins synthesized by Pechmann-Duisberg condensation against Drosophila melanogaster larvae and antibacterial effects.

On the background of the search of new insecticides friendly with the environment for replace those from synthesis organic origin with adverse effects on animals, soils and vegetables. It is reported in this study, the synthesis of a series of coumarins derivatives synthesized by Pechmann-Duisberg condensation assisted by microwave irradiation, their antibacterial and insecticidal activities. The most relevant results show that all compounds exhibit a mortality effect of 30-80% with doses between 10 and 100 μg/mL. This activity is related to alkyl or aryl substituent type at position C-4 coumarin skeleton. The coumarins 5, 6, 7 and 9 showed highest insecticidal activities, and these coumarins have at 4-position a bulky and low polarity substituent. The aim of this work is to find the effects of the 4-substitued coumarins with different lipophilic and bulky substituents. Even though many researchers were worked on coumarins, there are not reports about the insecticidal effects of specifically 4-substitued coumarins. The difference of our major findings versus current knowledge is in this scope of the research. On the other hand, was possible to find that a chloride at 4-position, drew to extend the antibacterial spectra.