3-Dimethylaminophenylboronic acid synthesis
- Product Name:3-Dimethylaminophenylboronic acid
- CAS Number:178752-79-9
- Molecular formula:C8H12BNO2
- Molecular Weight:165
16518-62-0
178752-79-9
The general procedure for the synthesis of 3-(N,N-dimethylamino)phenylboronic acid from 3-bromo-N,N-dimethylaniline was as follows: 3-bromo-N,N-dimethylaniline (500 mg, 2.50 mmol) was dissolved in tetrahydrofuran (THF, 8 mL) and the solution was cooled to -78 °C. At -78 °C, n-butyllithium (1.6 M in hexane, 1.56 mL, 3.75 mmol) was slowly added dropwise, and after the drop was completed, the reaction mixture continued to be stirred for 5 min by maintaining this temperature. Subsequently, trimethyl borate (1.11 mL, 10.0 mmol) was added and stirred at -78 °C for 1 h, followed by a slow warming to -20 °C over 20 min. 2 M hydrochloric acid (3 mL) was added and after stirring for 5 min, the reaction mixture was neutralized with saturated sodium bicarbonate (NaHCO3) solution. The mixture was extracted with ethyl acetate (3 × 10 mL), the organic phases were combined, and the crude product was concentrated under reduced pressure. Purification by silica gel fast column chromatography with acetone/dichloromethane (1:1, v/v) as eluent gave the target product 3-(N,N-dimethylamino)phenylboronic acid (251 mg, 61% yield).
16518-62-0
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178752-79-9
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Yield:178752-79-9 61%
Reaction Conditions:
Stage #1:3-bromo-N,N-dimethylaniline with n-butyllithium;Trimethyl borate in tetrahydrofuran;hexanes at -78 - -20; for 1.41667 h;
Stage #2: with hydrogenchloride in tetrahydrofuran;hexanes;water for 0.0833333 h;
Steps:
10.a
3-Bromo-N,N-dimethylaniline (500 mg, 2.50 mmol) was dissolved in THF (8 mL) and the solution was cooled to -78° C. n-Butyllithium (1.6M in hexanes, 1.56 mL, 3.75 mmol) was added drop-wise at -78° C. and the reaction mixture was stirred at this temperature for another 5 min. Trimethylborate (1.11 mL, 10.0 mmol) was added and the mixture was stirred for 1 h at -78° C. and was then left to warm to -20° C. over a period of 20 min. 2M HCl (3 mL) was added and the mixture was stirred for 5 min and was then neutralized by the addition of sat. NaHCO3 solution. The mixture was extracted with AcOEt (3×10 mL) and the combined organics were concentrated under reduced pressure to provide the crude boronic acid. Flash chromatography on silica gel eluting with acetone/CH2Cl2 1:1 provided 3-dimethylaminophenylboronic acid (251 mg, 61%).
References:
Kelly, Martha;Lee, Younghee;Liu, Bin;Fujimoto, Ted;Freundlich, Joel;Dorsey, Bruce D.;Flynn, Gary A.;Husain, Arifa US2006/270686, 2006, A1 Location in patent:Page/Page column 26
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16518-62-0
174 suppliers
$12.00/1g
178752-79-9
150 suppliers
$20.00/1g