Synthetic method for 3-amino-4-fluorophenylboronic acid
A technology of fluorophenylboronic acid and a synthetic method, which is applied in the field of preparation of 3-amino-4-fluorophenylboronic acid, can solve the problems of being expensive and difficult to obtain, and achieve the effects of low cost, simple and easy operation, and high yield
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[0020] Example 1
[0021] The first step of bromination: raw material o-fluoronitrobenzene (367g, 2.6mol) and concentrated sulfuric acid (3057g) are stirred uniformly, and N-bromosuccinimide (463g, 2.6mol) is added in batches. Warm up to 70 o C reaction. The control reaction in the gas phase is completed. The reaction solution was cooled to room temperature, then poured into ice, the product 2-fluoro-5-bromonitrobenzene was extracted with 200 ml of ethyl acetate, and the product was evaporated to dryness to obtain a crude brown solid. The crude product was recrystallized with petroleum ether, the GC was determined to be 98%, and the pure product was dried to obtain 198.7g, with a yield of 35.0%;
[0022] The second step of reduction: Mix 98% 2-fluoro-5-bromonitrobenzene (211g, 0.96mol) and iron powder (212g, 3.8mol), add 1200ml ethanol, and add glacial acetic acid (456g, 7.6 mol). Control the reaction liquid with oil bath 60 o C reaction, take the reaction liquid and co...
Example Embodiment
[0024] Example 2
[0025] The first step of bromination: raw material o-fluoronitrobenzene (367g, 2.6mol) and concentrated sulfuric acid (2600g) are stirred uniformly, and N-bromosuccinimide (463g, 2.6mol) is added in batches. Heat up to 65 o C reaction. The control reaction in the gas phase is completed. The reaction solution was cooled to room temperature, then poured into ice, the product 2-fluoro-5-bromonitrobenzene was extracted with 200 ml of ethyl acetate, and the product was evaporated to dryness to obtain a crude brown solid. The crude product was recrystallized with petroleum ether, the GC was determined to be 98%, and the pure product was dried to obtain 227.1g with a yield of 40.0%;
[0026] In the second step, 98% 2-fluoro-5-bromonitrobenzene (211g, 0.96mol) and iron powder (163g, 2.9mol) were mixed, 1200ml of ethanol was added, and glacial acetic acid (351g, 5.8mol) was added dropwise at room temperature. Control the reaction liquid with an oil bath 65 o C reactio...
Example Embodiment
[0028] Example 3
[0029] The first step of bromination: raw material o-fluoronitrobenzene (367g, 2.6mol) and concentrated sulfuric acid (2600g) are stirred uniformly, and N-bromosuccinimide (535g, 3.0mol) is added in batches. Warm up to 75 o C reaction. The control reaction in the gas phase is completed. The reaction solution was cooled to room temperature, then poured into ice, the product 2-fluoro-5-bromonitrobenzene was extracted with 200 ml of ethyl acetate, and the product was evaporated to dryness to obtain a crude brown solid. The crude product was recrystallized with petroleum ether, the GC was determined to be 98%, and the pure product was dried to obtain 215.7g with a yield of 38.0%;
[0030] In the second step, 98% 2-fluoro-5-bromonitrobenzene (211g, 0.96mol) and iron powder (134.4g, 2.4mol) were mixed, 1200ml of ethanol was added, and glacial acetic acid (290.4g, 4.8mol) was added dropwise at room temperature. ). Control the reaction liquid with an oil bath 55 o ...
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