Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 33070-32-5, name is 5-Bromo-2,2-difluorobenzodioxole, A new synthetic method of this compound is introduced below., SDS of cas: 33070-32-5
40 g (0.169 mol) of the 5-bromo-2,2-difluorobenzodioxole prepared in Example 1 and 108 g (121.5 ml) of tetrahydrofuran were placed in a 1 L reaction flask, and the mixture was stirred under a nitrogen atmosphere to cool the system to -10 C, control system temperature -10 ~ 0 C, A solution of 104 g (0.202 mol) of 20% isopropylmagnesium chloride in tetrahydrofuran was added dropwise to the system to control the dropping rate, and the dropwise addition was completed in about 3 hours. After the completion of the dropwise addition, the reaction was kept for 2 hours. The temperature was further lowered to -25 C, and 18.5 g (0.253 mol) of N,N-dimethylformamide was added dropwise, and the mixture was kept for 2 hours. Quenched by adding 200 ml of saturated ammonium chloride solution, adding 15% hydrochloric acid to adjust the pH value of 5-6, adding 250 g of dichloromethane to extract, layering, transfer the lower organic phase to 500 ml reaction flask at 60 C, and concentrate under reduced pressure until no fraction was obtained to give the intermediate product 2,2-difluoro-1,3-benzodioxan-5-carbaldehyde 28.6 g (0.153 mol). The system was cooled to 20-30 C, and 180 g of absolute ethanol was added.Under nitrogen protection, stirring was started, and 2.55 g (0.067 mol) of sodium borohydride was slowly added to the system in portions, and the addition was completed in about 3 hours. After the addition of heat for 30 min, the reaction was quenched by adding 800 g of water, and then extracted with 205 g of dichloromethane, and the mixture was allowed to stand for separation. The lower organic layer was evaporated and concentrated at 60 C, -0.08Mpa (G) to no fraction, and obtain the 2,2-fluorobenzo[d][1,3]dioxo-5-yl)methanol 25.7g, The purity of the gas was determined by gas chromatography to be 96% (0.131 mol, yield 77.7%, based on 5-bromo-2,2-difluorobenzodioxole)
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; Fuxin Da Deli Chemical Co., Ltd.; Nie Qiang; Zhang Jinsheng; Jiang Shan; Jia Yitong; (9 pag.)CN109503544; (2019); A;,
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