ChemicalBook CAS DataBase List 2,4-Difluorophenylboronic acid

2,4-Difluorophenylboronic acid synthesis

6synthesis methods

Product Name:2,4-Difluorophenylboronic acid
CAS Number:144025-03-6
Molecular formula:C6H5BF2O2
Molecular Weight:157.91

121-43-7

144025-04-7

144025-03-6

(B) A solution of trimethyl borate (25.98 g, 0.25 mol, Fluka) and 2,4-difluorophenylmagnesium bromide (0.25 mol) in tetrahydrofuran (200 mL) was added dropwise simultaneously to a reactor containing tetrahydrofuran (125 mL) over a period of 1 h under nitrogen protection, maintaining the reaction temperature at -15 °C. The reaction was carried out by stirring the reaction mixture for 15 min. After the dropwise addition, the reaction mixture was continued to be stirred at -15°C for 15 minutes. Subsequently, the temperature of the reaction system was raised to 0 °C and water (17.5 mL) and 10% sulfuric acid solution (125 mL) were slowly added over 10 and 15 min, respectively. After the reaction was complete, water (250 mL) was added to ensure complete dissolution of the product, which was subsequently extracted with ether (3 x 150 mL). The organic phases were combined and concentrated to dryness under reduced pressure to afford the crude 2,4-difluorophenylboronic acid (36.98 g, 90% purity, 84.3% yield), which was used directly in the subsequent cross-coupling reaction without further purification.

121-43-7
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$14.00/25mL

144025-04-7
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144025-03-6
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$6.00/1g

Yield:144025-03-6 84.3%

Reaction Conditions:

with sulfuric acid in tetrahydrofuran;water;

Steps:

20.B Preparation of 2,4-difluorophenylboronic acid

B) Trimethylborate (25.98 g; 0.25 moles--Fluka) and a solution of 2,4-difluorophenylmagnesiumbromide (0.25 moles) in tetrahydrofuran (200 ml) were contemporaneously added, in 1 hour, into a reactor containing tetrahydrofuran (125 ml) under nitrogen while keeping the temperature at -15° C. At the end of the addition, the reaction mixture was kept under stirring at -15° C. for 15 minutes. After bringing the temperature to 0° C., water (17.5 ml) and 10% sulfuric acid (125 ml) were added in 10 minutes and in 15 minutes respectively. After adding further water (250 ml) up to complete dissolution, the solution was extracted with ethyl ether (3*150 ml). The collected organic phases were evaporated to dryness obtaining a crude 2,4-difluorophenylboronic acid (36.98 g; titre 90%; 84.3% yield) which was used in the subsequent cross-coupling reaction without any further purification.

References:

US5312975,1994,A