Synthesis and Fungitoxicity of Novel Organophosphorus Compounds

Twenty novel organophosphorus derivatives have been prepared by the reaction of 0,0-diethylchlorophosphate/thiophosphate with Schiff bases derived from 2-amino-5-phenyl/substituted phenyl-1,3,4-thiadiazole. They have been characterized by IR and 1H NMR. The fungicidal activity against Colletotrichum falcatum, Fusarium oxysporum and Curvularia pallescens has been evaluated. Bis(O,O-diethylthiophosphate) derivatives containing Schiff base derived from 2-amino-5-(4-hydroxyphenyl)-1,3,4-thiadiazole and 2-hydroxyacetophenone and 0,O-diethylthiophosphate containing Schiff base derived from 2-amino-5-(4-chlorophenyl)-1,3,4-thiadiazole and 2-hydroxyacetophenone exhibited 100% mycelia inhibition against all the sugarcane pathogenic test fungi at 1000 ppm.