Inhibition of carotenoid biosynthesis by interaction of 2,6-diphenylpyridine derivatives with phytoene desaturation

Bleaching Herbicides: Action Mechanism in Carotenoid Biosynthesis, Structural Requirements and Engineering of Resistance

“…Most known bleaching compounds fit quite well as for example (Fig. 4, right) fluridone, flurochloridone, 2-phenyl-4-(3-chlorophenyl}-5-ethylaminopyrimidine (PCEP; Sandmann 2001b) and the 2-(3-trifluoromethylphenyl}-4-methylthio-6-(3-chlorophenyl}-pyridine (TMCP; Babczinski et al 1992). Other compounds like diflufenican are more difficult to put into this general model.…”

“…Since then, novel compounds have been identified as phytoene desaturase inhibitors. Among them are 2,6-diphenylpyridines (Kawamura et al 1991;Babczinski et al 1992), diarylpyrimidines (Kawamura et al 1993), tetrahydropyrimidinones (Babczinski et al 1995a), I,l'-biphenyl derivatives (Laber et al 1999), phenylpyrimidinones (Burdge 2000) and diphenylpyrrolidinones (Ogawa et al 2001). Typical and efficient bleaching compounds possess a central five-or sixmembered heterocycle carrying one or two substituted phenyl rings.…”

“…By comparison of fluridone derivatives it has already been concluded that the electron density of the substituent at position 4 determines the inhibitory activity (Sandmann and Boger 1992). An overlay of the structures reveals that the keto group in compounds like fluridone can be replaced by the imine groups of various heterocycles (Babczinski et al 1992). Other influences of the conjugated system of the heterocycle seem to be minor since the nonaromatic tetrahydropyrimidinones (Babczinski et al 1995b) and ketomorpholines (Sandmann and Mitchell2001) are also very potent inhibitors of phytoene desaturase.…”

“…Other influences of the conjugated system of the heterocycle seem to be minor since the nonaromatic tetrahydropyrimidinones (Babczinski et al 1995b) and ketomorpholines (Sandmann and Mitchell2001) are also very potent inhibitors of phytoene desaturase. In many bleachers the substituent at the six-membered central ring opposite the keto group or an electronically equivalent N imine (Babczinski et al 1992) is sterically well defined. It was suggested that either a methyl group at the para position as in phenylpyrimidinones and phenyltetrahydropyrimidines or a meta methylamino group as in phenylpyrimidazinones which cover a similar space results in an optimum inhibition of phytoene desaturase (Sandmann and Boger 1992).…”

Synthesis and herbicidal activities of novel 4-(3-trifluoromethylphenyl)-2H-pyridazin-3-one derivatives

“…Up to now, many novel compounds (e.g., 2,6-diphenylpyridines [5,6], phenoxypyridincarbonamides [7,8], diarylpyrimidines [9,10], 1,1'-biphenyl derivatives [11], tetrahydropyrimidinones [12,13], phenylpyrimidinones [14], and diphenylpyrrolidinones [15]) have been identified as phytoene desaturase inhibitors and commercialized. Most of the typical and efficient bleaching compounds possess a central five or six-membered heterocycle carrying one or two substituted benzene rings, and one of the benzene rings mostly links a meta-trifluoromethy group [16].…”