Novel 2-(benzylamino)-4-methyl-6-(trifluoromethyl)-1,3,5-triazines have the same 1,3,5-triazine skeleton as atrazine, although some of them, for example, ...2-(3-chlorobenzylamino)-4-methyl-6-(trifluoromethyl)-1,3,5-triazine pI 50(spinach) = 7.21, show a >3 times stronger photosynthetic electron transport inhibitory activity than atrazine pI 50(spinach) = 6.72. The new triazines have only one amino group at the triazine ring, and their molecular shapes are different from atrazine. The replacement of the bound 14Catrazine by 1,3,5-triazines was tested to determine whether the novel 1,3,5-triazine analogues exhibit the same binding pattern at the D1-protein as atrazine. It was found that 14Catrazine bound to the D1-protein was replaced by the triazine tested by a clearly competitive interaction. Obviously, the novel 1,3,5-triazines are attached to the same binding niche as atrazine. Keywords: (Benzylamino)-1,3,5-triazines; D1-protein; binding partners; replacement; atrazine-resistant Chenopodium
「INTRODUCTION」 Strong photosynthetic electron transport (PET) inhibitory and herbicidal activities of 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazines have been already reported by Kuboyama ...et al. 1, 2) and Inoue et al. 3) in our group. They tried molecular modifications on the benzylamino group of the compounds, namely substitution of the benzyl-benzene ring, N-alkylation, elongation of the methylene chain between amino group and benzene ring and absolute configuration of benzyl position. Consequently, introduction of a halogen or a trifluoromethyl group at 3- or 4-position of the benzene ring enhanced PET inhibitory activity. All these compounds 〔2-(3- or 4-substituted benzylamino)-4-methyl-6-trifluoromethyl- 1,3,5-triazine derivatives〕 exhibited higher PET inhibitory activity than that of simazine. N-Alkyl derivatives of these triazines completely lost both PET inhibitory and herbicidal activities. However, the effect of N-acylation of 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazines on phytotoxic activities has not been reported. In this study, some 2-(N-acylbenzylamino)-4-methyl-6-substituted-1,3,5-triazine derivatives were synthesized and evaluated to investigate the contribution of N-acylation of benzylamino group against PET inhibitory and herbicidal activities.
A series of 2-aralkylamino-1,3,5-triazine derivatives was synthesized and their photosynthetic electron transport (PET) inhibitory activity was evaluated. Investigation on the relationship between ...PET inhibitory activity and substituents on the triazine ring revealed that 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine exhibited a highly PET inhibitory activity. Furthermore, introduction of a halogen or a trifluoromethyl group at 3- or 4-position of the benzene ring enhanced PET inhibitory activity, exhibiting pI50 = 6.91-7.29. Their PET inhibition was about 10 times stronger than that of simazine. On the absolute configuration of chiral center in 2-methyl-4-(alpha-methylbenzylamino) 6-trifluoromethyl-1,3,5-triazine, (-)-enantiomer was around 100 times stronger than (+)-enantiomer. However, the PET inhibitory activity was decreased by N-alkylation of the benzylamino group in 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazine
The decrease of the number of ring nitrogen atoms of 2-benzylamino-4-methyl-6-trifluoro-methyl-1,3,5-triazines on herbicidal activity and inhibition of photosynthetic electron trans port (PET) was ...assayed using thylakoids from Spinacia oleracea or atrazine-resistant Chenopodium album. Three 2-benzylamino-4-methyl-6-trifluoromethyl-1,3,5-triazines, nine pyrimidines with a benzylamino-, methyl-and trifluoromethyl-group, 2-benzylamino-6-methyl-4-trifluoromethyl-pyridine and N-benzyl-3-methyl-5-trifluoromethylaniline were synthesized and assayed. 2-(4-Bromobenzylamino)-4-methyl-6-trifluoromethylpyrimidine exhibited the highest PET inhibitory activity against Spinacia oleracea thylakoids of all compounds tested. The 2-benzylaminopyrimidines and 2-methylpyrimidines having a 4-halobenzylamino group exhibited higher PET inhibition than atrazine and 2-trifluoromethylpyrimidines against Spinacia oleracea thylakoids. These PET inhibitory active compounds also exhibited a strong and similar inhibition both against atrazine-resistant Chenopodium album thylakoids as well as against thylakoids from wild-type Chenopodium. The herbicidal activity of 4-(4-bromoben-zylamino)-2-methyl-6-trifluoromethylpyrimidine was equivalent to that of known herbicides like simetryne, simazine or atrazine.
A series of the 2-benzylamino-1, 3, 5-triazine derivatives were synthesized and their herbicidal activity was evaluated. First investigation of substituents on the triazine ring revealed that the ...4-methyl-6-trifluoromethyl derivatives exhibited a highly herbicidal activity. Second investigation of substituent on the benzene ring in 2-benzylamino-4-methyl-6-trifluoromethyl-1, 3, 5-triazine revealed that the 3- or 4-halogeno derivatives on benzene ring exhibited a higher herbicidal activity. Also the PET (photosynthetic electron transport) inhibitory activity of 2-(3-chlorobenzylamino)-4-methyl-6-trifluoromethyl-1, 3, 5-triazine and 2-(4-chlorobenzylamino)-4-methyl-6-trifluoromethyl-1, 3, 5-triazine indicating a strong herbicidal activity in pot tests was higher than that of simazine and atrazine.
To investigate the substitution effect of the fluorine atom on methyl group, a methyl group of 2-benzylamino-4, 6-dimethyl-1, 3, 5-triazines was replaced with fluoromethyl, difluoromethyl and ...trifluoromethyl groups and photosynthetic electron transport (PET) inhibitory and herbicidal activities of these (fluorinated methyl)-1, 3, 5-triazine compounds were evaluated. With increasing the number of fluorine atom of fluorinated methyl group, PET inhibitory activity became higher. Furthermore by introduction of a halogen atom to the 4-position of the benzyl group, PET inhibitory activity was much improved compared to the triazines having an un-substituted benzylamino group. The (fluorinated methyl)-1, 3, 5-triazine derivatives with higher PET inhibitory activity showed also stronger herbicidal activity in soil and foliar application tests.
To investigate the substitution effect of the fluorine atom on methyl group, a methyl group of 2-benzylamino-4,6-dimethyl-1,3,5-triazines was replaced with fluoromethyl, difluoromethyl and ...trifluoromethyl groups and photosynthetic electron transport (PET) inhibitory and herbicidal activities of these (fluorinated methyl)-1,3,5-triazine compounds were evaluated. With increasing the number of fluorine atom of fluorinated methyl group, PET inhibitory activity became higher. Furthermore by introduction of a halogen atom to the 4-position of the benzyl group, PET inhibitory activity was much improved compared to the triazines having an un-substituted benzylamino group. The (fluorinated methyl)-1,3,5-triazine derivatives with higher PET inhibitory activity showed also stronger herbicidal activity in soil and foliar application tests.
New fluoroalkyl-substituted 1,3,5-triazine derivatives were synthesized and screened for herbicidal activity using a greenhouse pot test. Surprisingly, a series of ...2-alkyl-4-fluoroalkyl-6-aralkylamino-1,3,5-triazines e.g. 6-(4-bromo-benzylamino)-2-methyl-4- trifluoromethyl-1,3,5-triazine was found to possess strong pre- and post-emergence herbicidal activities, although the conventional herbicidal 1,3,5-triazines generally should have a 2-substituted-4,6-diamino-1,3,5-triazine structure for herbicidal activity. Our compounds show strong Photosynthetic Electron Transport inhibitory activity (PI(50) c7). Although their herbicidal effect is considered to be caused by a process similar to that for the conventional 1,3,5-triazine herbicide atrazine, they can control atrazine-resistant Chenopodium album effectively, and will thus form promising trial compounds for new triazine herbicide design.
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