2012-74-0Relevant academic research and scientific papers
Screening of by-products of esfenvalerate in aqueous medium using SBSE probe desorption GC-IT-MS technique
Colombo, Renata,Ferreira, Tanare C. R.,Yariwake, Janete H.,Lanza, Marcos R. V.
, p. 1831 - 1837 (2015/09/22)
The pyrethroids, their metabolites and by-products have been recognized as toxic to environment and human health. Despite several studies about esfenvalerate toxicity and its detection in water and sediments, information about its degradation products is still scanty. In this work, esfenvalerate degradation products were obtained by chemical oxidation with hydrogen peroxide and their structure was elucidated using a procedure known as stir bar sorptive extraction (SBSE) probe desorption gas chromatography-ion trap mass spectrometry (GC-IT-MS) analysis. This procedure consists of the thermal desorption of analytes extracted from a SBSE stir bar introduced by a probe into a gas chromatograph (GC) coupled to an ion trap mass spectrometry (IT-MS) system. Based on IT-MS data, a degradation pathway of esfenvalerate is proposed with ten products of chemical oxidation of esfenvalerate that are fully identified. Among these compounds, 3-phenoxybenzoic acid and 3-phenoxybenzaldehyde were detected, reported as being environmental metabolites of some pyrethroids, with endocrine-disrupting activity.
The first synthetic agonists of FFA2: Discovery and SAR of phenylacetamides as allosteric modulators
Wang, Yingcai,Jiao, Xianyun,Kayser, Frank,Liu, Jiwen,Wang, Zhongyu,Wanska, Malgorzata,Greenberg, Joanne,Weiszmann, Jennifer,Ge, Hongfei,Tian, Hui,Wong, Simon,Schwandner, Ralf,Lee, Taeweon,Li, Yang
scheme or table, p. 493 - 498 (2010/04/26)
Free fatty acid receptor 2 (FFA2) is a G-protein coupled receptor for which only short-chain fatty acids (SCFAs) have been reported as endogenous ligands. We describe the discovery and optimization of phenylacetamides as allosteric agonists of FFA2. These novel ligands can suppress adipocyte lipolysis in vitro and reduce plasma FFA levels in vivo, suggesting that these allosteric modulators can serve as pharmacological tools for exploring the potential function of FFA2 in various disease conditions.
Purification and characterization of a novel pyrethroid hydrolase from Aspergillus niger ZD11
Liang, Wei Q.,Wang, Zhuo Y.,Li, He,Wu, Pei C.,Hu, Ji M.,Luo, Na,Cao, Li X.,Liu, Yu H.
, p. 7415 - 7420 (2007/10/03)
The pyrethroid pesticides residues on foods and environmental contamination are a public safety concern. Pretreatment with pyrethroid hydrolase has the potential to alleviate the conditions. For this purpose, a fungus capable of using pyrethroid pesticides as a sole carbon source was isolated from the soil and characterized as Aspergillus niger ZD11. A novel pyrethroid hydrolase from cell extract was purified 41.5-fold to apparent homogeneity with 12.6% overall recovery. It is a monomeric structure with a molecular mass of 56 kDa, a pl of 5.4, and the enzyme activity was optimal at 45°C and pH 6.5. The activities were strongly inhibited by Hg2+, Ag+, and p-chloromercuribenzoate, whereas less pronounced effects (5-10% inhibition) were observed in the presence of the remaining divalent cations, the chelating agent EDTA and phenanthroline. The purified enzyme hydrolyzed various insecticides with similar carboxylester. trans-Permethrin is the preferred substrate.
A Rearrangement Route to Fenvaleric Acid
Luzzio, Frederick A.,Fitch, Richard W.
, p. 498 - 501 (2007/10/03)
(±)-Fenvaleric acid 2, the key intermediate for the preparation of the pesticide esfenvalerate 1, was prepared by a novel sequence which first involves the Henry reaction of 2-methyl-1-nitropropane and 4-chlorobenzaldehyde. The nitroaldol reaction provided nitroalcohol 5 which was then reduced to the corresponding aminoalcohol 6. Submission of 6 to an aminopinacol rearrangement promoted by nitrous acid deamination then afforded aldehyde 8 through a 1,2-aryl shift. The product fenvaleric aldehyde 8 was then converted to the title compound 2 by a modified Jones oxidation.
Studies on the synthesis of chiral 2-(p.chlorophenyl)-3-methylbutanoic acid, a key-precursor of Fenvalerate, by hydrocarbonylation reactions
Botteghi, Carlo,Bona, Denis Dalla,Paganelli, Stefano,Marchetti, Mauro,Sechi, Barbara
, p. 101 - 107 (2007/10/03)
The preparation of racemic 2-(p.chlorophenyl)-3-methylbutanoic acid (2), a building block for (S,S)-Fenvalerate (an important broad spectrum insecticide), was effected by rhodium catalyzed hydroformylation of 2-methyl-1 -(p.chlorophenyl) propene (4) in the presence of excess of triphenylphosphine to inhibit substrate isomerization followed by mild oxidation of the resulting aldehyde 6; an overall yield of 88% was reached. Olefin 4 exhibits a very low tendency to undergo both hydrocarboethoxylation and hydrocarboxylation in the presence of palladium complexes as catalysts. Enantioselective hydrocarbonylation reactions carried out on olefin 4 afford unsatisfactory chemical and optical yields of the optically active ester 5 or acid 2. Springer-Verlag 1996.
Asymmetric Catalytic Alkylation of 4-Chlorophenylacetic Acid
Mi, A. Q.,Wang, Z. Y.,Jiang, Y. Z.
, p. 1957 - 1960 (2007/10/02)
Using N-(monoalkyl)-α,β-diphenyl-β-hydroxy ethylamine as chiral ligands, 46.2percent enantiomeric excess was obtained in the asymmetric catalytic alkylation of 4-chlorophenylacetic acid.
Process for the preparation of 2-(4-chlorophenyl)-3-methylbutyric acid
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, (2008/06/13)
A process for the preparation of 2-(4-chlorophenyl)-3-methylbutyric acid from 4-chlorobenzaldehyde by conversion of the benzaldehyde to 3-(4-chlorophenyl)-2-methylpropenal, 3-(4-chlorophenyl)-2-methylpropanol, 1-(4-chlorophenyl)-2-methylpropene-1, and 2-(4-chlorophenyl)-2-methylbutyraldehyde, and finally to the desired corresponding butyric acid.
