Natural products as sources of new fungicides (I): synthesis and antifungal activity of Kakuol derivatives against phytopathogenic fungi

Abstract

In order to establish an advanced structural-activity relationship (SAR) and to explore the feasibility of kakuol analogues with better anti-fungi activity, a series of 2-hydroxy-4,5-methylenedioxyaryl ketones were conveniently synthesized by the Friedel-Crafts acyl reaction, etherification reaction, reduction reaction and oximation reaction. Their structures characterized by ¹H and ¹³C NMR and HRMS methods. Their in vitro antifungal activities were assayed. Most of the derivatives showed a remarkable in vitro activity, and some of them appeared significantly more effective than a commercial fungicide hymexazol as positive control. In particular compounds 2h and 2i, were found active with a IC₅₀ value of 3.1 mg/ml and 2.9 mg/ml against Glomerella cingulate, which suggested that 2-hydroxy-4,5-methylenedioxyaryl ketones might be a promising candidates in the development of new antifungal compounds. Compounds 2e, 5 and 6 also exhibited high antifungal activities on a wide range of organisms, which might be considered as leading compounds in the development of new antifungal compounds.

DOI: http://doi.dx.org/10.5564/mjc.v15i0.331

Mongolian Journal of Chemistry 15 (41), 2014, p94-100