1918-00-9Relevant articles and documents
Preparation methods of 2-bromo-3,6-dichlorobenzoic acid and dicamba
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, (2019/06/05)
The invention provides a preparation method of dicamba. The preparation method comprises the following steps: S1), in the presence of a catalyst, 2-bromobenzoic acid is subjected to a chlorination reaction in chlorosulfonic acid or concentrated sulfuric acid, and 2-bromo-3,6-dichlorobenzoic acid is obtained; S2), 2-bromo-3,6-dichlorobenzoic acid is subjected to a methoxylation reaction, and dicamba is obtained. Compared with the prior art, 2-bromo-3,6-dichlorobenzoic acid is obtained from 2-bromobenzoic acid after the directional chlorination reaction, and dicamba can be obtained by the methoxylation reaction. The methods have the advantages of easily available raw materials, low comprehensive cost, high methoxylation reaction selectivity, high total yield, stable product quality and simple process, and facilitate industrial implementation.
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.
Preparation method of dicamba
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, (2019/06/05)
The invention provides a preparation method of dicamba. The preparation method comprises the steps as follows: A) salicylic acid and bromine or hydrogen bromide are subjected to a reaction in concentrated sulfuric acid, 5-bromosalicylic acid is obtained; B) 5-bromosalicylic acid and chlorine are subjected to a chlorination reaction, 5-bromo-3,6-dichlorosalycylic acid is obtained; C) 5-bromo-3,6-dichlorosalycylic acid is subjected to a debromination reaction under the alkaline condition and under the action of metal powder, and 3,6-dichlorosalycylic acid is obtained; D) 3,6-dichlorosalycylic acid and halomethane are subjected to an etherification reaction in a mixed solvent of water and methanol, and methyl-3,6-dichloro-2-methoxybenzoate is obtained; E) methanol is removed by distillation;F) a system after distillation is left to stand for laying, an organic phase is distilled, and dicamba methyl ester is obtained; G) dicamba methyl ester is subjected to alkaline hydrolysis, acidification and drying, and dicamba is obtained. The route comprises few steps and has low difficulty, the equipment requirement and investment are lower, continuous production can be realized, no three wastes are produced, and the product yield and purity are higher.
Selective removing method of benzene ring hydroxyl para-bromine and preparation method of dicamba
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, (2019/06/05)
The invention provides a selective removing method of benzene ring hydroxyl para-bromine. The method comprises following steps: a compound represented as formula (I) in the description is subjected toa reaction under the alkaline condition and the action of metal powder to remove hydroxyl para-bromine ions, and a compound represented as formula (II) in the description is obtained. The benzene ring hydroxyl para-bromine ions are selectively removed under the alkaline condition and the action of the metal powder, the reaction has higher selectivity, conversion rate and reaction rate are high, and a prepared product has higher purity.
A catalytic oxidation of the synthesis of the herbicide dicamba 2 - methoxy - 3, 6 - II [...] method
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Paragraph 0030-0033, (2019/11/04)
The invention relates to a method for synthetizing a herbicide-dicamba (2-methoxy-3,6-dichloro-salicylic acid) through catalytic oxidation. The method is characterized in that the dicamba is obtained through oxidation of air, oxygen or ozone by taking 2-substituent 3,6-banair as a raw material and adopting a composite catalyst. The method disclosed by the invention has the advantages that the operation is simple, the raw material is easy to obtain, the cost is low, the catalyst can be recycled, and the method is more environment-friendly and is more suitable for industrial production.
Preparation methods of 3,6-dichloro-2-bromotoluene and dicamba
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, (2019/06/05)
The invention provides a preparation method of dicamba. The preparation method comprises the following steps: S1) in the presence of a catalyst, 2-bromotoluene is subjected to a chlorination reactionin chlorosulfonic acid or concentrated sulfuric acid, and 3,6-dichloro-2-bromotoluene is obtained; S2), 3,6-dichloro-2-bromotoluene is subjected to an oxidation reaction and a methoxylation reaction in sequence, and dicamba is obtained. Compared with the prior art, 3,6-dichloro-2-bromotoluene is obtained from 2-bromotoluene after the directional chlorination reaction, and dicamba can be obtained by the oxidation reaction and the methoxylation reaction. The methods have the advantages of easily available raw materials, low comprehensive cost, high methoxylation reaction selectivity, high totalyield, stable product quality and simple process, and facilitate industrial implementation.
Preparation method of dicamba
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, (2019/01/23)
The invention relates to a preparation method of dicamba. The method comprises the following steps: preparing 2, 5-dichlorobenzoic acid as a starting raw material; further esterifying with methyl alcohol in an acidic condition; processing to obtain a product; further substituting with bromine under the effect of aluminum tribromide; reacting the obtained product with methyl alcohol under the effect of a catalyst; processing; and further hydrolyzing the obtained product to obtain the final product, namely dicamba. Compared with a traditional synthesizing method, the method has the advantages that few synthesizing steps are performed; the reaction process is simple; the reaction temperature is low; the operation safety is improved; the reaction processing in each step is simple, so that thereaction can be conveniently carried out; and the yield is high.
A dicamba preparation method (by machine translation)
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Paragraph 0041-0059, (2019/06/05)
The invention provides a method for preparing dicamba, comprises the following steps: A) 3, 6 - II [...] and halogenated methane in water and methanol in mixed solvent of the etherification reaction, to obtain 3, 6 - dichloro - 2 - methoxybenzoic acid methyl ester; B) distilled to remove the methanol; C) after the distillation system layered, organic phase distillation, to obtain baphia methyl ester; D) baphia methyl ester by the alkaline hydrolysis, acidification, drying, get baphia. The invention water and methanol mixed solvent as 3, 6 - II [...] etherification reaction solvent, reaction after first distilled to remove the methanol, then distillation baphia methyl ester, in order to distill and craft has replaced the traditional preparation method recrystallization process, and omits the decoloring this process, compared with the traditional process, the obtained baphia the color of the product is pure white, inch high, and improves the working environment on the site workers, more environment-friendly, alkaline hydrolysis process of the less water, the economical efficiency, technical and environmental protection, improves the stability of the product. (by machine translation)
Synthesis method for raw material drugs of dicamba
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Paragraph 0022, (2018/01/12)
The invention relates to a synthesis method for raw material drugs of dicamba. The synthesis method for the raw material drugs of dicamba comprises the following steps: taking 2,5-dichlorophenol as a starting material, carrying out esterification under the actions of an organic solvent and an organic esterification reagent to generate 2,5-dichlorophenol acetate; dissolving 2,5-dichlorophenol acetate in the organic solvent and adding a catalyst to generate Fries rearrangement, thus generating 3,6-dichloro-2-hydroxyacetophenone; making 3,6-dichloro-2-hydroxyacetophenone react with a methylating reagent under the action of an acid-binding agent to obtain 3,6-dichloro-2-methylacetophenone; synthesizing dicamba (3,6-dichloro-2-methoxybenzoic acid) under the action of 3,6-dichloro-2-methylacetophenone. The synthesis method for the raw material drugs of dicamba disclosed by the invention is simple in process, highly available in raw materials and the catalyst, low in cost, simple in post-treatment operation, low in environmental pollution, high in safety of reaction operation, high in reaction yield, good in product quality and favorable for industrialization.
NOXIOUS ARTHROPOD CONTROL AGENT CONTAINING AMIDE COMPOUND
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, (2017/08/26)
An object of the present invention is to provide a compound having the controlling activity on a noxious arthropod, and a noxious arthropod controlling agent containing an amide compound of formula (I): wherein X represents a nitrogen atom or a CH group, p represents 0 or 1, A represents a tetrahydrofuranyl group or the like, R1, R2, R3, R4, R5, R6 and R7 represent a hydrogen atom or the like, n represents 1 or 2, Y represents an oxygen atom or the like, m represents any integer of 0 to 7, and Q represents a C1-8 chain hydrocarbon group optionally having a phenyl group or the like, has the excellent noxious arthropod controlling effect.