The synthesis of several novel triazine ring hydrolysis products of <i>n</i>‐[[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino]carbonyl]‐2‐(3,3,3‐trifluoropropyl)benzenesulfonamide

Heard, Nina E.; Overman, Monica C.

doi:10.1002/jhet.5570320535

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…Thus, the reaction of 10 with chlorosulfonyl isocyanate, followed by hydrolysis of sulfonyl intermediate, furnished urea 8 in moderate yield. 26 Hydrolysis of 10 under basic conditions and subsequent carbamylation of 11 led to urea 9. Interestingly, the unprotected hydroxyl group in 11 did not interfere significantly with isocyanate reagent ( Scheme 1A ).…”

Section: Resultsmentioning

confidence: 99%

Synthetic approach to iodosulfuron-methyl and metsulfuron-methyl metabolites and their application for water analysis

Rakowiecki,

Studzińska,

Ścianowski

et al. 2024

RSC Adv.

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Section: Resultsmentioning

confidence: 99%

Synthetic approach to iodosulfuron-methyl and metsulfuron-methyl metabolites and their application for water analysis

Rakowiecki,

Studzińska,

Ścianowski

et al. 2024

RSC Adv.

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Hydrolysis of prosulfuron at pH 5: evidence for a resonance-stabilized triazine cleavage product

Bray¹,

Heard²,

Overman³

et al. 1997

Pestic. Sci.

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: Prosulfuron is a herbicide for the selective control of broadleaf weeds in corn. In order to examine the e †ect of pH on the stability of prosulfuron in aqueous solution, a hydrolysis experiment was conducted in bu †er at pH 5, 7 and 9 utilizing [phenyl-14C] and [triazine-14C]prosulfuron. Prosulfuron was found to be stable under neutral and basic conditions and hydrolytically unstable under acidic conditions days). One of the major routes of deg-(T " D10 radation at pH 5 involved hydrolysis of the sulfonylurea bridge to yield the corresponding phenyl-and triazine-cleavage products and minor amounts of desmethyl-prosulfuron and dihydroxymethyltriazine. In addition to these hydrolysis products, an unknown species was observed at signiÐcant levels after 30 days (D20% of the applied dose). A large-scale experiment was subsequently performed to generate additional material for the spectroscopic characterization and identiÐcation of this unknown degradate. A thorough spectral evaluation of this unknown revealed a resonance-stabilized derivative of the parent molecule which stemmed from a hydrolytic opening of the triazine ring of desmethylprosulfuron. Although this triazine ring-opening phenomenon was Ðrst described for chlorsulfuron, a structurally related sulfonylurea herbicide, the structure of the product was only postulated. Recently, Cambon et al. described the hydrolysis kinetics of thifensulfuron and thifensulfuron-methyl which resulted in cleavage of the sulfonylurea bridge and triazine ring-opening. Our results support these Ðndings and we herein describe the characterization and identiÐcation of this resonance-stabilized species by comparison with the recently synthesized authentic reference standard.

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Fate of chlorsulfuron in the environment. 1. Laboratory evaluations

Strek

1998

Pestic. Sci.

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:The behaviour and fate of chlorsulfuron in aqueous and soil systems were examined in laboratory studies. Aqueous hydrolysis was pH-dependent and followed pseudo-Ðrst-order degradation kinetics at 25¡C, with faster hydrolysis occurring at pH 5 (half-life 24 days) than at either pH 7 or 9 (half-lives [365 days). Degradation occurred primarily by cleavage of the sulfonylurea bridge to form the major metabolites chlorobenzenesulfonamide (2-chlorobenzenesulfonamide) and triazine amine (4-methoxy-6-methyl-1,3,5-triazin-2-amine). This route is a major degradation pathway in water and soil systems. Aqueous photolysis (corrected for hydrolysis) proceeded much more slowly (half-life 198 days) than aqueous hydrolysis and is not expected to contribute signiÐ-cantly to overall degradation. Hydrolysis in soil thin-layer plates exposed to light (half-life 80 days), however, progressed at a much faster rate than in dark controls (half life 130 days), which suggests that a mechanism other than direct photolysis may have been operative. An aerobic soil metabolism study (25¡C) in a Keyport silt loam soil (pH 6É4, 2É8% OM) showed that degradation was rapid (half-life 20 days). Dissipation in an anaerobic sediment/water system (initial pH of water phase 6É7, Ðnal pH 7É4) progressed much more slowly (half-life [365 days) than in aerobic soil systems. Major degradation products in aerobic soil included the chlorobenzenesulfonamide and triazine amine as in the aqueous hydrolysis study. Neither of these degradation products exhibited phytotoxicity to a variety of crop and weed species in a glasshouse experiment, and both exhibited an acute toxicological proÐle similar to that of chlorsulfuron in a battery of standard tests. Demethylation of the 4-methoxy group on the triazine moiety and subsequent cleavage of the triazine ring is another pathway found in both aqueous solution and soils, though di †erent bonds on the triazine amine appear to be cleaved in the two systems. Hydroxylation of the benzenesulfonamide moiety is a minor degradation pathway found in soils. Two soils amended with 0É1 and 1É0 mg kg~1 chlorsulfuron showed slight stimulation of nitriÐcation. The 1É0 mg kg~1 concentration of chlorsulfuron resulted in minor stimulation and inhibition of 14C-cellulose and 14C-protein degradation, respectively, in the same soils. Batch equilibrium adsorption studies conducted on four soils showed that adsorption was low in this system 13È54). Soil thin-layer (K oc chromatography of chlorsulfuron and its major degradation products demon-(R f \ 0É55È0É86) strated that the chlorobenzenesulfonamide had slightly less mobility and that the (R f \ 0É34È0É68) triazine amine was much less mobile than chlorsulfuron. In an aged column (R f \ 0É035È0É40) leaching study, subsamples of a Fallsington sandy loam 5É6, OM 1É4%) or a Flanagan silt (pH water loam 6É4, OM 4É0%) were treated with chlorsulfuron, aged moist for 30 days in a glass-(pH water house and then placed upon a prewet column of the same soil type prior to initiation of leaching....

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The synthesis of several novel triazine ring hydrolysis products of n‐[[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino]carbonyl]‐2‐(3,3,3‐trifluoropropyl)benzenesulfonamide

Abstract: The syntheses of four hydrolysis products isolated from environmental studies on the title compound are reported. Spectral comparison of these synthetic standards with study isolates provided proof for sulfonyl urea intact triazine ring hydrolysis.

Cited by 4 publications

References 2 publications

Synthetic approach to iodosulfuron-methyl and metsulfuron-methyl metabolites and their application for water analysis

Synthetic approach to iodosulfuron-methyl and metsulfuron-methyl metabolites and their application for water analysis

Hydrolysis of prosulfuron at pH 5: evidence for a resonance-stabilized triazine cleavage product

Fate of chlorsulfuron in the environment. 1. Laboratory evaluations

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