Structure-activity relationships on the selective herbicidal activity between rice plant and barnyard grass by the N-phenyl substituents in 2-(4-(6-chloro-2-benzoxazolyloxy)-phenoxy)-N-phenyl propionamide derivatives

2-(4-(6-chloro-2-benzoxazolyloxy) phenoxy)-N-phenyl propionamide 유도체 중 N-phenyl 치환체들에 의한 벼와 피의 선택적 제초활성에 미치는 구조-활성관계

  • Published : 1999.12.30

Abstract

A some of synthesized 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenyl propionamide derivativesa substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) for those her- bicidal activities with post emergence in up land. The selectivity of substrates against rice plant better than that of Fenoxaprop-ethyl. The structure activity relationship (SAR) n the selectivity of N-phenyl substituents were analyzed by the Free-Wilson and Hansch method. The SAR approach against barnyard grass is shown that the optimal ($({\pi})_{opt.}=1.60$) hydrophobicity and electron donating effects ($0<{\sigma}$ & 0$(ES)_{opt.}=0.87$) so that the herbicidal activity against rice plant can be decreased. The significance of these results on the selectivity between barnyard grass and rice plant is discussed. And it is assumed that the 2-ethoxy-3-methoxy-4-dimethylamino group substituent ($pI_{50}$=6.60, 1g/ha) is selected as the most highest herbicidal activity against barngard grass in green house.

Keywords

2-(4-(6-chloro-2-benzoxazolyloxy) phenoxy)-N-phenylpropionamide;Herbicidal activity;Barnyard grass(Echinochloa crus-galli);Up land;Selectivity;QSAR. Hansch & Free-Wilson method