Efficacy of Organophosphorus Derivatives Containing Substituted Chalcone Thiosemicarbazones and Dithiocarbazates Against Fungal Pathogens of Sugarcane

Ten novel organophosphorus derivatives have been prepared by the reactions of O,O-diethylchlorophosphate with two important series of substituted chalcones viz., substituted chalcone thiosemicarbazones and substituted chalcone dithiocarbazates. The derivatives have been characterized on the basis of analysis and spectral (IR, 1 H NMR) data. Fungicidal activity of these derivatives against Colletotrichum falcatum , Fusarium oxysporum , and Curvularia pallescens have been evaluated. The screening results have been correlated with the structural features of the tested compounds. Organophosphorus derivatives containing 2,2'-dihydroxybenzalacetophenone thiosemicarbazone, 2-chlorobenzal-2'-hydroxyacetophenone thiosemicarbazone, 2-chlorobenzal-2'-hydroxy acetophenone-S-benzyldithiocarbazate proved more active than some prevalent commercial synthetic fungicides.