A kind of method for preparing 2-methyl-4-formaldoxime methyl benzoate
A technology of methyl oximino benzoate and bromobenzoic acid, which is applied in the field of preparation of pharmaceutical intermediates, can solve the problems of high production raw material costs, harsh reaction conditions, and many impurities in products, and achieve low production costs, short synthetic routes, and efficient production processes. Simple operation effect
Active Publication Date: 2018-07-06
荆门医药工业技术研究院 +1
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Problems solved by technology
In the Vilsmeier-Haack reaction of the first step of this route, n-butyllithium should be used at -78 o C reaction, the reaction conditions in the industry are relatively harsh, and a large amount of n-butyl lithium has a greater safety risk, and there are many types of raw material reagents used in the second step esterification reaction process, and the post-reaction treatment is complicated. As a result, the cost of production raw materials is higher, the product impurities are more and the yield is lower
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Embodiment 1
[0025] (1) Preparation of methyl 2-methyl-4-bromobenzoate: Dissolve 1,5 g of 2-methyl-4-bromobenzoic acid in 30 ml of methanol, add 2 ml of thionyl chloride to it, and 70 o C was refluxed for 6 hours, the solution was cooled to room temperature, 30 ml of saturated sodium carbonate solution was added, fully stirred, 15 ml of ethyl acetate was used to extract twice, and the organic layer was successively washed with 10 ml of water twice, and washed with 10 ml of saturated brine, Dry over anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to obtain brown-red methyl 2-methyl-4-bromobenzoate 2, 5.17 g, yield 97%.
[0026]
[0027] (2) Preparation of methyl 2-methyl-4-cyanobenzoate: Add 20 ml DMF to dissolve 2-methyl-4-bromobenzoic acid methyl ester 2, 5.17 g obtained in step (1), and then Add 10.2 g of cuprous cyanide, stir, the solid matter dissolves quickly, the solution is clear, and heated to 160 o C was reacted for 12 hours, cooled to room tempera...
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The invention discloses a method for preparing 2-methyl-4-formaldoxime methyl benzoate. The method comprises the following steps: performing acylating chlorination on 2-methyl-4-bromobenzoic acid, carrying out methanol esterification and cyano substitution, and then performing nucleophilic addition elimination with hydroxylamine hydrochloride under alkaline conditions to obtain a target product. The method has the advantages that the process route is simple; reaction conditions are mild; the product yield is high; the total yield reaches 61 percent; the product quality is high; the appearance is white solid; the purity reaches 99.2 percent.
Description
technical field [0001] The invention relates to the field of preparation of pharmaceutical intermediates, in particular to a method for preparing methyl 2-methyl-4-formaldoxime benzoate. Background technique [0002] The research and development of new insecticides plays a very important role in the prevention and control of insecticide resistance and the control of its harm in animal husbandry. The compound fluralaner is a new type of isazoline insecticide that is safe to mammals, has high insecticidal activity and broad spectrum, such as against pests such as ticks, fleas, lice, hemiptera and diptera All have good insecticidal activity. At present, fluralaner has been sold and promoted as a veterinary drug in countries such as Europe and the United States, but it is still in the preliminary research stage in China and has not yet formed commercial production. Methyl 2-methyl-4-formaldoxime benzoate is an important intermediate for the synthesis of isoxazoline compound fl...
Claims
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IPC IPC(8): C07C249/04C07C251/48
CPCC07C67/08C07C249/04C07C253/14C07C251/48C07C255/57C07C69/76
Inventor 王勇李立威黄道友
Owner 荆门医药工业技术研究院