20.ピリミジン誘導体のプロトポルフィリノーゲンIXオキシダーゼ阻害活性(口頭発表)

概要

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We found that novel 5-arylpyrimidine derivatives with fluoroalkyl groups at 2- and 4-position on the pyrimidine ring showed high level of herbicidal activity, and obvious necrotic symptoms were observed. The substituted phenyl group of the 5-position of the pyrimidines, exhibited herbicidal activity, was similar to a highly functionalized phenyl group of typical protopophynogen IX oxidase (protox) inhibitors. So, we checked the protox inhibitory activitiy of the pyrimidine derivatives presented, and their intensity of each inhibitory activity was evaluated and calculated as the pI_<50> values. The pyrimidinone I (I: R^2=CF_3, Xn=4-Cl) showed moderate level of inhibitoy activity and the pI50 value of was 5.5. Protox inhibitory activity of 4-methoxypyrimidine derivative II (II: R^1=Me, R^2=CF_3, Xn=4-Cl) was not observed at all. On the other hand, the pI_<50> value of 4-methoxypyrimidine derivative III (III: R^1=Me, R^2=CF_3, R^3=propargyl) bearing a 1,4-benzoxazin-3-one ring was 7.1. These findings indicated that introduction of a 1,4-benzoxadin-3-one ring at 5-position on the 4-methoxypyrimidine ring significantly enhanced the protox inhibitory activity. Among the compounds evaluated, the pyrimidinone derivative IV (IV: R^2=CHF_2, R^3=propargyl) exhibited the most potent protox inhibition (pI_<50>=8.4), and completely controlled all weeds tested at 1.9g a.i./ha application.
2009-10-06