Preparation method of sedaxane
A technology of flufenoxam and difluoromethyl pyrazole amide is applied in the field of preparation of flufenapyr, can solve the problems of expensive catalyst, unacceptable industrialization cost and high cost, and achieves the advantages of being beneficial to industrialization and total income. The effect of high rate and obvious cost advantage
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[0016] like figure 1 As shown, the present invention provides a preparation method of fluoxafen, comprising the following steps: Step S1, in an organic solvent, adding 2-bicyclopropyl halobenzene and Mg, and Grignard reaction to obtain Grignard Reagent intermediate; Step S2, adding boronic acid ester to the Grignard reagent intermediate, reacting and then hydrolyzing to obtain 2-bicyclopropylbenzeneboronic acid intermediate; Step S3, adding 2-bicyclopropylbenzene to the organic solvent Boric acid intermediate, catalyst, base, difluoromethyl pyrazole amide, and coupling reaction obtains fluoxafen; the reaction formula of the above steps is:
[0017]
[0018] R=methyl, ethyl; X=F, Cl, Br, I.
[0019] In this embodiment, specifically, in the step S1, adding 2-bicyclopropyl halobenzene and Mg to the organic solvent, and Grignard reaction to obtain the Grignard reagent intermediate includes: under nitrogen protection, to a The organic solvent, 2-bicyclopropyl halobenzene and M...
Embodiment 2
[0034] like image 3 As shown, 2-bicyclopropyl bromobenzene is used as a raw material to synthesize fluoxafen, and the target product is prepared in a small test:
[0035] (1) 23.6g (0.10mol) of 2-bicyclopropyl bromobenzene, 3g (0.125mol) of Mg, 50mL of THF were put into a 250mL reaction flask, and the reaction was initiated by heating and stirring at 60°C, and the reaction was incubated for 5h, cooled, and the next step was directly used for subsequent use;
[0036] (2) Put 20.8 g (0.2 mol) of trimethyl borate and 100 mL of THF into another 500 mL reaction flask, add the Grignard reagent intermediate of the first step dropwise at 0 °C, and keep the temperature at 0 °C for 3 h after the dropwise addition, and then the intermediate control is qualified. Concentrated hydrochloric acid was added dropwise to adjust the pH to 2, and the crude boronic acid intermediate was directly used in the next step after liquid separation, desolvation and recovery of THF;
[0037] (3) Put 100 ...
Embodiment 3
[0039]Based on Example 1 and Example 2, it can be seen that under the same conditions of using copper acetate as a catalyst, the total yield of synthesizing fluoxafen using 2-bicyclopropyl bromobenzene as a raw material is 75% higher than that of 2-bicyclopropyl bromobenzene. Cyclopropyl chlorobenzene is 68% of raw material synthesis fluoxafen, so on the basis of embodiment 2, with 2-bicyclopropyl bromobenzene as raw material, carry out the third step reaction catalyst screening, obtain Table 1 to verify The total yield of various catalysts.
[0040] Table 1
[0041] serial number catalyst total yield 1 Cuprous Chloride 62％ 2 Cuprous Bromide 68％ 3 copper acetate 75％ 4 Ferric chloride 35％
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