Síntese e Avaliação do Efeito Fungicida de Derivados do Timol Sobre Fusarium Solani da Pimenta-do-Reino

Abstract

The Fusarium solani f. sp. piperis is the causative agent of one of the main diseases in black pepper plantations. This filamentous fungus can cause root rot, yellow wilt and even the death of infected plants, causing crop loss and losses to pipericulturists. The methods used in the application of fusariosis of black pepper are carried out with the prevention of the fungus, with the use of high standard seedlings, monitoring of the plantation and eradication of symptomatic plants. However, these precautions have little efficiency and so far there is no record of resistant cultivars or specific fungicide for the disease registered in the phytosanitary pesticide system. Therefore, the objective of this project was to synthesize 15 new ether and triazole compounds derived from the natural product thymol for the development of new fungicides before the control of fusariosis in black pepper. The obtainment of new compounds derived from thymol was performed by the 1,3-dipolar Huisgen cycloaddition reaction, involving a "click chemistry" strategy, by coupling this natural prototype with commercial functionalized azides. Confirmation and structural elucidation of the collected data was carried out using the spectroscopic techniques of 1H and 13C NMR, Infrared and Mass Spectrometry. The synthesized compounds dissipated between 35-92% and by evaluating the antifungal activity against Fusarium solani, it was possible to conclude that among the nine triazole compounds used, seven wasted fungicide, with a MIC of 57 μg mL-1 compared to 7 μg mL-1 of thiabendazole, a commercial fungicide used as a standard. It is noteworthy that the compound 2-chloro-3-(2-isopropyl-5-methylphenoxy) naphthalene-1,4-dione (2b), thymol / naphthoquinone hybrid, inhibited a concentration of 14 μg mL-1 . These results indicate a potential of thymol derivatives and contribution to research in search of new agrochemicals that can be obtained without controlling the fusariosis disease of black pepper.