- Chiral resolution of the insecticide fipronil enantiomers and the simultaneous determination of its major transformation products by high-performance liquid chromatography interfaced with mass spectrometry
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A high-performance liquid chromatography–mass spectrometry (HPLC-MS) method was developed using a chiral column based on amylose tris(3-chloro-5-methylphenylcarbamate) for analysis of fipronil (a popular insecticidal nerve agent) and the related transformation products. The optimized method reached the goal of the simultaneous and complete separation of the multiple fiproles in a single run, including the chiral separation of fipronil enantiomers, fipronil metabolites, and photoproducts. The efficacy of such a method was demonstrated by its application in analyzing a series of fipronil samples exposed to sunlight conditions. In general terms, our study provided experimental approaches and an efficient analytical tool for monitoring the environmental fate of fipronil as well as its multitransformation products upon its applications either in agricultural or any other areas.
- Paolini, Léa,Hausser, Nicolas,Zhang, Tong
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supporting information
p. 473 - 483
(2022/01/22)
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- PROCESS FOR THE PREPARATION OF FIPRONIL AND ANALOGUES THEREOF
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The present invention relates to a new and efficient process for preparing 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(trifluoromethylthio)-IH-pyrazole-3-carbonitrile (hereinafter referred to as compound of formula I), which is useful as an intermediate for the antiparasitic agent fipronil, and a process for preparing 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethyl sulfinylpyrazole (hereinafter referred to as compound of formula II or fipronil). In one aspect, there is provided a process for preparing fipronil comprising: a) a step of reacting CF3S(=O)ONa with the compound of formula (III) in the presence of a reducing/halogenating agent; and b) a step of oxidizing the compound of formula (I) obtained in step a) in the presence of a selective oxidizing agent, under suitable conditions, wherein the selective oxidizing agent selectively effects oxidation of (I) to the corresponding sulfoxide, Fipronil. In certain exemplary embodiments, the selective oxidizing agent is MHSO5, wherein M is an alkaline metal cation.
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Page/Page column 29-30
(2009/07/18)
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- A convenient conversion of pyrazolyl disulfide to sulfides by sodium dithionite and synthesis of sulfoxides
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Indirectly introduce trifluoromethylthio-, alkylthio-, and trifluoromethylsulfinyl to pyrazole ring by a convenient reaction of a pyrazolyl disulfide with F3CBr and alkyl halides in the presence of sodium dithionite at room temperature. Followed by selective oxidation with H2O2 or trichloroisocyanuric acid (TCCA) to give trifluoromethylsulfenyl phenylpyrazole, alkylsulfenyl phenylpyazole, trifluoromethylsulfinyl phenylpyrazole 4a (a highly efficient insecticide named fipronil) and ethylsulfinyl phenylpyrazole 4c derivatives, respectively.
- Tang, Ri-Yuan,Zhong, Ping,Lin, Qiu-Lian
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p. 948 - 953
(2008/02/10)
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- Antiparasitical agents and methods for treating, preventing and controlling external parasites in animals
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This invention provides for antiparasitical agents and methods for treating, preventing and controlling external parasites in animals.
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Page/Page column 27
(2008/06/13)
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- Mechanisms for selective toxicity of fipronil insecticide and its sulfone metabolite and desulfinyl photoproduct
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Fipronil, an N-phenylpyrazole with a trifluoromethylsulfinyl substituent, initiated the second generation of insecticides acting at the γ-aminobutyric acid (GABA) receptor to block the chloride channel. The first generation includes the polychlorocycloalkanes α-endosulfan and lindane. In this study, we examine the mechanisms for selective toxicity of the sulfoxide fipronil and its sulfone metabolite and desulfinyl photoproduct relative to their target site interactions in vitro and ex vivo and the importance in fipronil action of biooxidation to the sulfone. Differences in GABA receptor sensitivity, assayed by displacement of 4'-ethynyl-4-n-[2,3-3H2]- propylbicycloorthobenzoate ([3H]EBOB) from the noncompetitive blocker site, appear to be a major factor in fipronil being much more toxic to the insects (housefly and fruit fly) than to the vertebrates (humans, dogs, mice, chickens, quail, and salmon) examined; in insects, the IC50s range from 3 to 12 nM for fipronil and its sulfone and desulfinyl derivatives, while in vertebrates, the IC50 average values are 1103, 175, and 129 nM for fipronil, fipronil sulfone, and desulfinyl fipronil, respectively. The insect relative to the vertebrate specificity decreases in the following order: fipronil > lindane > desulfinyl fipronil > fipronil sulfone > α-endosulfan. Ex vivo inhibition of [3H]EBOB binding in mouse brain is similar for fipronil and its sulfone and desulfinyl derivatives at the LD50 dose, but surprisingly, at higher doses fipronil can be lethal without detectably blocking the [3H]EBOB site. The P45 inhibitor piperonyl butoxide, acting in houseflies, increases the metabolic stability and effectiveness of fipronil and the sulfone but not those of the desulfinyl compound, and in mice it completely blocks the sulfoxide to sulfone conversion without altering the poisoning. Thus, the selective toxicity of fipronil and fipronil-derived residues is due in part to the higher potency of the parent compound at the insect versus the mammalian GABA receptor but is also dependent on the relative rates of conversion to the more persistent and less selective sulfone metabolite and desulfinyl photoproduct.
- Hainzl, Dominik,Cole, Loretta M.,Casida, John E.
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p. 1529 - 1535
(2007/10/03)
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- Derivatives of N-phenylpyrazoles
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N-Phenylpyrazole derivatives of the formula: wherein R1 represents cyano, nitro, halogen, acetyl or formyl:, R2 represents R5SO2, R5SO or R5S in which R5 is optionally halogen substituted alkyl, alkenyl or alkynyl;, R3 represents a hydrogen atom or a group NR6R7 wherein R6 and R7 each represent hydrogen, alkyl, alkenylalkyl, alkynylalkyl, formyl, optionally halogen substituted alkanoyl, optionally halogen substituted alkoxycarbonyl, or alkoxymethyleneamino, halogen, or R6 and R7 together form a cyclic imide and R4 represents a substituted phenyl group possess arthropodicidal, plant nematocidal, anthelmintic and anti-protozoal properties; their preparation, compositions containing them and their use are described.
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