p-Aromatic Isothiocyanates: Synthesis and Anti Plant Pathogen Activity

Abstract

In this study, a series of p-aromatic isothiocyanates are prepared by reacting p-aromatic amines with carbon disulphide and further treating with molecular iodine to yield corresponding isothiocyanate derivatives. The structures of newly synthesized compounds are confirmed by IR, NMR, and MS data. Activity of the products against plant pathogenic fungi and bacteria is tested and the structure-activity relationship is approached. p-Nitrophenyl isothiocyanate most efficiently inhibits Rhizoctonia solani and Erwinia carotovora. The order of seven aromatic isothiocyanates antifungicidal activity is following: p-nitrophenyl > p-methoxyphenyl > p-chlorophenyl > p-methylphenyl > p-ethylphenyl > phenyl > p-fluorophenyl. For antibacterial activity, the order was p-nitrophenyl > p-chlorophenyl > p-methylphenyl > p-ethylphenyl > p-fluorophenyl > phenyl > p-methoxyphenyl. The present study indicates that some of the compounds exhibit promising antimicrobial activity and can be used as an alternative to the traditional synthetic fungicides for controlling R. solani and E. carotovora.