Synthesis and biological assay of O, O-diaryl O-2-chloroethyl phosphorothionates against Rhizoctonia solani and Sclerotium rolfsii

Twenty new O,O-diaryl O-2-chloroethyl phosphorothionates, having different phenyl substitutions, have been synthesized and characterized by physico-chemical techniques. The compounds have been evaluated for their fungicidal activity against two phytopathogenic fungi viz., Rhizoctonia solani and Sclerotium rolfsii. The most active compounds are O,O-di(pentachlorophenyl) O-2-chloroethyl phosphorothionate (ED 5 0 =0.419 mgmL - 1 ) and O,O-di(2-methylphenyl) O-2-chloroethyl phosphorothionate (ED 5 0 =0.426 mg mL - 1 ) against R. solani and S. rolfsii respectively.