247922-29-8Relevant academic research and scientific papers
Topramezone intermediate and topramezone preparation method
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, (2020/04/06)
The invention relates to the field of organic synthesis, in particular to a topramezone intermediate and a topramezone preparation method. The topramezone preparation method comprises the following steps: 3-[3-halogen-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole and cyanide are subjected to a substitution reaction to obtain 3-[3-cyano-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole; hydrolysis reaction is performed on 3-[3-cyano-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole under the action of acid or alkali to obtain 2-methyl-3-(4, 5-dihydroisoxazole-3-yl)-4-methylsulfonyl benzoic acid; and 2-methyl-3-(4, 5-dihydroisoxazole-3-yl)-4-methylsulfonyl benzoic acid and 1-methyl-5-hydroxypyrazole are condensed and rearranged to generate topramezone. According to the topramezone intermediate and the topramezone preparation method provided by the invention, the use of an expensive palladium catalyst and a dangerous butyl lithium reagent is avoided, the yield isrelatively high, the cost is reduced, the process is simplified, the defects in the prior art are overcome, and the industrial value is achieved.
Preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole
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, (2020/11/12)
The invention belongs to the field of chemical synthesis, the invention relates to a preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5 -dihydroisoxazole. The 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5 -dihydroisoxazole is prepared by taking 2, 3-dimethylaniline as an initial raw material for reaction. The method comprises the following steps: diazotizing, brominating and oximating the 2, 3-dimethylaniline to obtain an oximated product, and is mainly characterized in that the oximated product is oxidized by a one-pot method, and then subjected to isoxazole cyclization to obtain the target product. The method has the advantages that monopoly of a traditional route is broken through in the last two steps, and the method is safe, environmentally friendly, easyto industrialize and promising in market prospect.
Preparation method and application of topramezone
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Paragraph 0038-0039; 0051-0053, (2020/08/02)
The invention discloses a preparation method and application of topramezone, and the preparation method comprises the following steps: taking 2-methylbenzaldehyde, a bromination reagent, a catalyst, hydroxylamine hydrochloride, an alkali, ethylene gas, a sulfonylation reagent and a preset solvent as reaction raw materials, and preparing 3-[3-bromo-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole through a first reaction process; taking diethyl malonate, triethyl orthoformate, nickel sulfate, monobasic saturated carboxylic acid, methylhydrazine, a hydrocarbon solvent, an ethanol solutionand hydrochloric acid as reaction raw materials, and carrying out a second reaction process to prepare 1-methyl-5-hydroxypyrazole; and taking the 3-[3-bromo-methyl-6-(methylsulfonyl) phenyl]-4, 5 dihydroisoxazole,-1-methyl-5-hydroxypyrazole, triethylamine, potassium carbonate, palladium chloride, triphenylphosphine, 1, 4-dioxane, water, a saturated NaHCO3 solution and a hydrochloric acid solutionas reaction raw materials, and carrying out a third reaction process to prepare the topramezone. The problems that a sulfur-containing intermediate can emit odor and the raw materials are difficult to obtain in the existing process are solved.
Synthesis method and application of topramezone impurity
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, (2019/10/01)
The invention discloses a synthesis method of topramezone impurity. The method includes: taking 2, 3-dimethylaniline as the starting raw material, carrying out methyl sulfidation, bromination, oxidation, oximation and chlorination ring-closing to synthesize 3-[3-bromo-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole, and carrying out condensation with 1-methyl-5-hydroxypyrazole under an alkaline condition to synthesize 3-[2-methyl-3-(1-methyl-1H-pyrazole-5-oxyl)-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole. The invention also discloses application of the corresponding product. The synthesis method provided by the invention has the characteristics of simple operation, easily control process, and a product yield of 40%-80%. The obtained product can be used as a standard substancefor detecting and monitoring the synthesis of topramezone.
Preparation method of 3-substituted phenyl-4,5-dihydroisoxazole derivative and application and intermediate thereof
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, (2019/10/01)
The invention relates to a preparation method of a 3-substituted phenyl-4,5-dihydroisoxazole derivative and application and an intermediate thereof. A cyano compound (V) is converted into an N-hydroxybenzimidium compound (VII), and then 3-substituted phenyl-4,5-dihydroisoxazole intermediate (IX) is synthesized through a diazotization chlorination reaction and a dipolar cycloaddition reaction; a reaction condition is mild and controllable, the reaction selectivity in each step is good, the yield is relatively high, production of some byproducts is avoided, the product quality is guaranteed, andindustrialization of a whole technological route is easy to implement.
Method and novel intermediate products for producing isoxazolin-3-yl-acylbenzenenes
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, (2008/06/13)
The present invention describes a process for preparing isoxazoles of the formula I where: R1is hydrogen, C1-C6-alkyl, R2is hydrogen, C1-C6-alkyl, R3, R4, R5are each hydrogen, C1-C6-alkyl or R4and R5together from a bond, R6is a heterocysclic ring, n is 0, 1 or 2; which comprises preparing an intermediate of the formula VI where R1, R3, R4and R5are each as defined above, followed by halogenation, thiomethylation, oxidation and acylation to give compounds of the formula I. Furthermore, the invention describes novel intermediates for preparing the compounds of the formula I and novel processes for preparing the intermediates.
