ProtoporphyrinogenIXOxidase Inhibitors

Manufacturing Approaches of New Halogenated Agrochemicals

“…[13] The enzyme protoporphyrinogen IX oxidase (PPO), which catalyzes the oxidation of protoporphyrinogen IX to proto- porphyrin IX by molecular oxygen, is one of the most established herbicidal targets for weed control. [14] In plants, protoporphyrin IX is the substrate for the biosynthesis of chlorophyll, which is a key pigment for photosynthesis. Inhibition of the PPO results in the accumulation of protoporphyrin IX, which is a photosensitizer of triplet oxygen.…”

“…The non-selective grasses herbicide tiafenacil 8, contains a racemic methyl 3-(2-sulfanylpropanoyl-amino)-propanoate side chain at the same trifluoromethyl-substituted 3-aryl-uracil building block as the PPO herbicides butafenacil and 7. [14] The preparation of 16 is possible by the acid promoted cyclization reaction of the commercially available ethyl N-(4-chloro-2fluoro-phenyl)carbamate 14 (CAS: 114108-90-6) and ethyl (E)-4,4,4-trifluoro-3-methylbut-2-enoate 15. The precursor 17 can be prepared via chlorosulfonation of 16 (yield 89 %) and reduction.…”

“…According to the synthetic pathway in Scheme 3 the Suzuki reaction of the 2-(4-chloro-2-fluoro-3-methoxy-phenyl)-1,3,2-dioxaborinane 27 and methyl 4-acetamido-3,6-dichloro-pyridine-2-carboxylate 28 leads to the precursor 29, which is finally depro-tected to give 25 in good yield. [21] For the second auxine herbicide 26, the pyridine aldehyde 30 (commercially available (CAS: 1613459-84-9), but can be also prepared in 96 % yield, based on a route that was used to incorporate 14 31, which undergoes an O-benzylation reaction. [22] An accelerated enzymatic degradation of the 3'-methoxy group at the phenyl moity in 25 and its pyridine 2-methoxycarbonyl group at the pyridine ring in aerobic soils leads to the herbicide 25a, which has physiological and phenotypic effects similar to those induced by the natural plant hormone indole-3-acetic acid (IAA).…”

Organic Isocyanates and Isothiocyanates: Versatile Intermediates in Agrochemistry

“…Its hydroxy function is then alkylated with the required disubstituted benzyl chloride to obtain the uracil herbicide benzfendizone ( 98 ) (Scheme 20 ). 59 60 61…”

Protoporphyrinogen‐IX‐oxidase Inhibitors

“…ha À1 . BASF reported the following new chemistries: the benzoic acid derivatives 98, with good post-emergence activity in redroot pigweed and common lambsquarter, as well as potential use as cotton desiccants or defoliants [105], and 99 [106]; aminosulfonylamino phenyl uracil derivatives (100) [107]; and benzosulfonamides (101) [108]. Figure 3.28 shows these and other Protox inhibitors with diverse groups at the aromatic meta position, which are discussed below.…”