583-78-8Relevant articles and documents
New metabolites in the degradation of α- and γ- hexachlorocyclohexane (HCH): Pentachlorocyclohexenes are hydroxylated to cyclohexenols and cyclohexenediols by the haloalkane dehalogenase LinB from Sphingobium indicum B90A
Raina, Vishakha,Rentsch, Daniel,Geiger, Thomas,Sharma, Poonam,Buser, Hans Rudolf,Holliger, Christof,Lal, Rup,Kohler, Hans-Peter E.
, p. 6594 - 6603 (2008)
Technical hexachlorocyclohexane (HCH) and lindane are obsolete pesticides whose former production and use led to widespread contaminations posing serious and lasting health and environmental risks. Out of nine possible stereoisomers, α-, β-, γ-, and -HCH are usually present at contaminated sites, and research for a better understanding of their biodegradation has become essential for the development of appropriate remediation technologies. Because haloalkane dehalogenase LinB was recently found responsible for the hydroxylation of β-HCH, δ-HCH, and δ-pentachlorocyclohexene (δ-PCCH), we decided to examine whether β- and γ-PCCH, which can be formed by LinA from α-and γ-HCH, respectively, were also converted by LinB. Incubation of such substrates with Escherichia coli BL21 expressing functional LinB originating from Sphingobium indicum B90A showed that both β-PCCH and γ-PCCH were direct substrates of LinB. Furthermore, we identified the main metabolites as 3,4,5,6-tetrachloro-2-cyclohexene-1-ols and 2,5,6-trichloro-2-cyclohexene-1,4-diols by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. In contrast to α-HCH, γ-HCH was not a substrate for LinB. On the basis of our data, we propose a modified γ-HCH degradation pathway in which γ-PCCH is converted to 2,5-cyclohexadiene-1,4-diol via 3,4,5,6-tetrachloro-2-cyclohexene- 1-ol and 2,5,6-trichloro-2-cyclohexene-1,4-diol.
Method for hydroxylating aromatic compound
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Paragraph 0108-0109, (2020/06/17)
The invention provides a method for directly hydroxylating an aromatic compound. The method comprises the following steps: dissolving the aromatic compound in a solvent, adding hydrogen peroxide and anitroxide free radical compound, and reacting. The nitroxide free radical compound is used as a catalyst, hydrogen peroxide is used as an oxidizing agent, and hydroxylation of the aromatic compound is directly catalyzed and oxidized. Compared with a traditional process, the method has the advantages of high product selectivity, mild reaction conditions, reusability of the catalyst, easiness in separation of oxidation products and raw materials and the like.
A new process to prepare 3,6-dichloro-2-hydroxybenzoic acid, the penultimate intermediate in the synthesis of herbicide dicamba
Walker, Daniel P.,Harris, G. Davis,Carroll, Jeffery N.,Boehm, Terri L.,McReynolds, Matthew D.,Struble, Justin R.,van Herpt, Jochem,van Zwieten, Don,Koeller, Kevin J.,Bore, Mangesh
, p. 1032 - 1036 (2019/03/17)
Glyphosate [N-(phosphonomethyl)glycine] is a broad spectrum, post-emergent herbicide that is among the most widely used agrochemicals globally. Over the past 30 years, there has been a development of glyphosate-resistant weeds, which pose a significant challenge to growers and crop scientists, resulting in lower crop yields and increased costs. 3,6-Dichloro-2-methoxybenzoic acid (dicamba) is the active ingredient in XtendiMax a standalone herbicide developed by Bayer Crop Science to control broadleaf weeds, including glyphosate-resistant species. 3,6-Dichloro-2-hydroxybenzoic acid (3,6-DCSA) is the penultimate intermediate in the synthesis of dicamba. Existing dicamba manufacturing routes utilize a high temperature, high pressure Kolbe-Schmitt carboxylation to prepare 3,6-DCSA. Described in this Letter is a new, non-Kolbe-Schmitt process to prepare 3,6-DCSA from salicylic acid in four chemical steps.
