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ChemicalBook CAS DataBase List Dibenzofuran-4-boronic acid
100124-06-9

Dibenzofuran-4-boronic acid synthesis

12synthesis methods
In a 300 ml three-necked flask, 7.2 g of 4-bromodibenzofuran was dissolved in -78° C. anhydrous tetrahydrofuran (THF) under an argon atmosphere. Then, 20 ml of an n-butyl lithium-n-hexane solution (1.6 M, 1.1 eq) was added and stirred for 1 hour. 4.23 ml (1.3 eq) of trimethoxyborane (B(OMe)3) was added and stirred for 2 hours, and the temperature of the reaction system was increased to room temperature. 200 ml of 1 N hydrochloric acid was added into the reactant and stirred for 3 hours. An organic layer was separated, and solvents were distilled off. In the crude product thus obtained, hexane was added. Precipitated product was filtered to obtain 4.94 g of dibenzofuran-4-boronic acid as a white solid (yield 80%).
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Yield:100124-06-9 94%

Reaction Conditions:

Stage #1: 4-bromodibenzofuranwith n-butyllithium in tetrahydrofuran at -78; for 1.5 h;Inert atmosphere;
Stage #2: Triisopropyl borate in tetrahydrofuran at 20; for 8 h;

Steps:

4.1 (5-(4-([2,2':6',2"-teridopyridine]-4'-yl)phenyl)-5H-benzofuro[3,2-c]indole)Preparation

(1) 4-bromodibenzofuran (7.4 g, 30 mmol, 1 eq) in a 50 ml three-necked flask,Add dry tetrahydrofuran solution, cool to -78 ° C, replace N2, three times,To ensure the oxygen-free environment of the system, add n-butyl lithium (2.5M, 13.2ml,After 33 mmol, 1.1 eq), the reaction was kept at -78 ° C for 1.5 h, and triisopropyl borate (ρ = 0.815 g/ml, 7.6 ml, 33 mmol, 1.1 eq) was added dropwise. After the addition was completed, the temperature was raised to room temperature for 8 h. After the dropwise addition of dilute hydrochloric acid, the reaction was quenched, distilled under reduced pressure to give tetrahydrofuran, dissolved in dichloromethane, washed with anhydrous magnesium sulfate, dried, filtered, and the filtrate was recrystallized.White solid product4-boronic acid dibenzofuran6 g (yield 94%).

References:

CN109897029,2019,A Location in patent:Paragraph 0063-0066

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