Synthesis of novel aryl(4-substituted pyridin-3-yl)methyl carbamates and their herbicidal activity

Abstract

A certain number of aryl(4-substituted pyridin-3-yl)methyl carbamates and related compounds were synthesized, and their herbicidal activities against weeds and phytotoxicity against transplanted rice were evaluated. The herbicidal efficacy varied with the structures of the aryl group, carbamoyl group, and substituent on the 4-position of the pyridine ring. It was revealed that the combination of the 4-(trifluoromethyl)pyridin-3-yl group and the naphthalen-1-yl group is favorable to achieve superior herbicidal activity without showing phytotoxicity in transplanted rice. Among these analogs, naphthalen-1-yl[4-(trifluoromethyl)pyridin-3-yl]methyl N,N-dimethylcarbamate 2a showed an excellent herbicidal efficacy as a new candidate for paddy rice herbicide. A (−)-enantiomer of 2a exhibited higher activity than its (+)-enantiomer. The mechanism of herbicidal action would be considered to be inhibition of obtusifoliol 14α-methyl demethylase P450. © Pesticide Science Society of Japan