ChemicalBook CAS DataBase List 3,4,5-Trifluorophenylboronic acid

3,4,5-Trifluorophenylboronic acid synthesis

9synthesis methods

Product Name:3,4,5-Trifluorophenylboronic acid
CAS Number:143418-49-9
Molecular formula:C6H4BF3O2
Molecular Weight:175.9

Add 42mmol (10.08g) of magnesium chips into a 1000mL four-necked flask, add 2 pieces of iodine, and then add 200mL of anhydrous 2-methyltetrahydrofuran, heat the temperature to 50°C, and then slowly let it cool down to 40°C. And then drip 4-5mL of 3,4,5-trifluorobromobenzene 84.4g (0.4mol) and 50mL 2-methyltetrahydrofuran mixed solution, trigger the Grignard reaction, the temperature will rise rapidly after the reaction is initiated, use The temperature is lowered to 10-15°C in an ice-water bath, and a mixture (1) composed of 3,4,5-trifluorobromobenzene 84.4g (0.4mol) and 50mL 2-methyltetrahydrofuran (1), trimethyl borate is added dropwise. A mixture of 44 grams (0.42 mol) of ester and 50 mL of 2-methyltetrahydrofuran (2).The speed of the mixed solution (1) and the mixed solution (2) is kept the same, the dropping speed is controlled, and the dropping temperature is kept at 10-15°C . After the dropping is completed, the reaction is continued at room temperature for 8 hours.After the reaction is over, the reaction solution is slowly poured into dilute hydrochloric acid, and after the addition is complete, stir for 0.5-1.5h, separate the liquids, and then extract the aqueous phase twice, combine the organic phases, dry with anhydrous sodium sulfate, spin dry, and Recrystallization of ethyl chloride gave 3,4,5-Trifluorophenylboronic acid with a yield of 78% and a content of 99.6%.

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2-methoxy-5,5-dimethyl-1,3,2-dioxaborinane

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138526-69-9 Synthesis

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143418-49-9
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Yield:143418-49-9 90.3%

Reaction Conditions:

Stage #1: 5-bromo-1,2,3-trifluorobenzenewith iodine;magnesium in 2-methyltetrahydrofuran at 40 - 50;
Stage #2: 2-methoxy-5,5,-dimethy-1,3,2-dioxaborinane in 2-methyltetrahydrofuran at 20 - 30; for 4 h;
Stage #3: hydrogenchloride in 2-methyltetrahydrofuran;water monomer; for 1.5 h;Solvent;Temperature;

Steps:

5-6 Example 5

Add 48mmol (11.7g) of magnesium scraps into a 1000mL four-necked flask, add 2 iodine, then add 200mL 2-methyltetrahydrofuran, after heating the temperature to 50°C, slowly let it cool down to 40°C naturally, then Add dropwise 5 mL of a mixed solution consisting of 84.4 g (0.4 mol) of 3,4,5-trifluorobromobenzene/50 mL of 2-methyltetrahydrofuran to initiate a Grignard reaction. After the reaction is initiated, the temperature will rise rapidly. The temperature was lowered to 20-30°C, and a mixed solution (1) consisting of 84.4 g (0.4 mol) of 3,4,5-trifluorobromobenzene and 50 mL of 2-methyltetrahydrofuran was added dropwise, and a mixture consisting of methoxyneopentylglycol boron 80.6 g (0.56 mol) of the acid ester and 50 mL of 2-methyltetrahydrofuran constitute a mixed solution (2). The speed of dropping the mixed solution (1) and the mixed solution (2) was kept the same, the dropping speed was controlled, and the dropping temperature was kept at 20-30 °C. After the dropping was completed, the reaction was continued at room temperature for 4 h.After the reaction was completed, the reaction solution was slowly poured into dilute hydrochloric acid, stirred for 1.5 h after the dropwise addition, and the liquids were separated. The aqueous phase was extracted twice, the organic phases were combined, and dried over anhydrous sodium sulfate. Spin dry and recrystallize from dichloromethane to obtain a white powder with a yield of 90.3%, a content of 99.4%, and related impurities below 200 ppm.

References:

CN114149460,2022,A Location in patent:Paragraph 0040-0045