2005•Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal ChemistryRequires access
Synthesis and QSAR of O,O-diaryl O-ethyl phosphorothionates for their fungicidal activity against Rhizoctonia solani and Sclerotium rolfsii
Bijul Lakshman A, R. L. Gupta
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Abstract
A series of twenty-one O,O-diaryl O-ethyl phosphorothionates having different substituents in the phenyl ring have been synthesized, characterized by various spectroscopic techniques and tested in vitro for fungicidal activity against Rhizoctonia solani and Sclerotium rolfsii. Among these, O,O-di(2,4-dimethylphenyl) O-ethyl phosphorothionates exhibit highest fungicidal activity (ED50 =0.066 mg mL -1 , R. solani and 0.042 mg mL -1 , S. rolfsii) The quantitative structure activity relationship (QSAR) obtained by means of multiple regression analysis technique using the fungicidal activity data and physico-chemical parameters of benzene ring substituents reveal that the size and shape of ortho-substituents expressed in terms of STERIMOL L and B1 parameters i.e, high value of length parameter, [∑L(o)] and low value of width parameter, [∑B1(o)] favour high fungicidal activity against both fungi. IPC: Int.Cl. 7 A 61K 35/00 // A 61 P 31/10