250592-88-2Relevant academic research and scientific papers
Improved method for preparing topramezone
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, (2018/07/30)
The invention discloses an improved method for preparing topramezone and belongs to the technical field of chemical synthesis. The improved method takes 3-nitro-o-xylene as a raw material and is characterized in that the topramezone is obtained through oximation reaction, ethylene cyclization, palladium carbon reduction, diazotization, aldehydelation, oxidation and condensation rearrangement reaction; under optimal conditions, the total yield is 33.7 percent, the raw material is cheap and easy to obtain, the treatment is convenient in the whole process, the yield is relatively high, and a certain significance in industrialized production is realized.
Method for preparing 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole
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Paragraph 0018; 0019, (2016/10/31)
The invention discloses a method for preparing 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole by a one-pot reaction. The method comprises the following steps: a reaction vessel is used, a chlorination reaction of a material 2-methyl-6-nitrobenzaldoxime is carried out in a solvent halogenated hydrocarbon, after the reaction, nitrogen is used for air stripping of excessive chlorine, and a cyclization reaction is carried out with ethene and an acid binding agent, in order to obtain a 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole reaction solution. After washing, drying and precipitation of the reaction solution, the product 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole is obtained. The reaction is shown as follows. The method for preparing 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole by the one-pot reaction has the advantages of simple process flow, operation safety, mild reaction condition, equipment at normal temperature and under normal pressure and low production cost; the risk that a chlorination intermediate 2-methyl-6-nitrobenzoyl chloride oxime is easy to explode during precipitation is avoided. The reaction yield is high, and the yield is higher than 85%, other raw materials and solvents are cheap and easily available, the raw material cost is low, 'three wastes (waste gas, waste water and industrial residue)' are less, and the method is good for industrial production.
