Dibenzofuran-4-boronic acid

Synthesis of dibenzofuran-4-boronic acid (0048) 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)Synthesis of Intermediate 22 (0146) (0147) Under a nitrogen atmosphere, Intermediate 20 (2.47 g, 10 mmol) was dissolved in anhydrous tetrahydrofuran (40 mL), and then cooled to −78° C. n-butyllithium (2.5 M, 4 mL) was slowly added dropwise, stirred at 0° C. for 1 hr, and then cooled to −78° C. again. Trimethyl borate (12.47 g, 12 mmol) was added dropwise, and stirred for 12 hrs at normal temperature. After the reaction was terminated, a 2N aqueous HCl solution was added, stirred for 30 min, and extracted with diethyl ether. (0148) The organic layer was dried over anhydrous magnesium sulfate, suctioned, and concentrated. The resultant compound was purified by column chromatography eluting with Hex:EA=5:1, to obtain Intermediate 22 (1.55 g, 73percent). (0149) Intermediate 22 MS(FAB): 212(MUnder a nitrogen atmosphere, Intermediate 16 (2.47 g, 10 mmol) was dissolved in anhydrous tetrahydrofuran (40 mL), and then cooled to −78° C. n-butyllithium (2.5 M, 4 mL) was slowly added dropwise, stirred at 0° C. for 1 hr, and then cooled to −78° C. again. Trimethyl borate (12.47 g, 12 mmol) was added dropwise, and stirred for 12 hrs at normal temperature. After the reaction was terminated, a 2N aqueous HCl solution was added, stirred for 30 min, and extracted with diethyl ether. The organic layer was dried over anhydrous magnesium sulfate, suctioned, and concentrated. The resultant compound was purified by column chromatography eluting with Hex:EA=5:1, to obtain Intermediate 18 (1.55 g, 73percent). Intermediate 18 MS (FAB): 212(MIn a 2 L four-necked round bottom flask equipped with a stirrer, a Liebig condenser fitted with a calcium chloride tube, a nitrogen inlet tube, a 500 mL pressure equalizing dropping funnel and a thermometer, 75.0 g (0.445 mol) of dibenzofuran and 75.0 g Tetrahydrofuran (THF) 900 mL was placed, and under a nitrogen stream, It was cooled to below -60 ° C. with an acetone-dry ice bath. Then, 310 mL (0.498 mol) of an n-hexane solution of n-butyllithium (concentration: 1.6 M) (hereinafter abbreviated as n-BuLi) was dropped at -50 ° C. or lower, and then the isobaric dropping funnel was washed with 150 mL of THF Was added to the reaction solution. Subsequently, the reaction was carried out at -50 ° C. or lower for 1 hour, then the temperature was returned to room temperature and stirred for 4 hours. Then, again cooled in an acetone-dry ice bath to below -60 ° C., 60 mL (0.538 mol) of trimethyl borate [B (OMe) 3] was dropped at -45 ° C. or lower, then the isobaric dropping funnel was washed with 150 mL of THF Was added to the reaction solution. Subsequently, after stirring at -45 ° C. or lower for 30 minutes, the acetone-dry ice bath was removed, the temperature was returned to room temperature, and post-reaction was carried out for 15 hours to obtain a boron reaction solution.Next, 340 mL of concentrated hydrochloric acid and 860 mL of water were placed in a 3 L four-necked round bottom flask equipped with a stirrer, a Liebig condenser (not required), a 2000 mL dropping funnel and a thermometer, and then cooled in an ice bath to -5 ° C. Subsequently, the boron reaction solution was dropped at a temperature not exceeding 10 ° C., and the mixture was stirred at 10 ° C. or less for 1 hour, then returned to room temperature and stirred for 3 hours.The resulting reaction solution was transferred to a 3 L separating funnel, the organic layer was separated, and the aqueous layer was extracted three times with 400 mL of diethyl ether. Then, the organic layers were combined, washed with 400 mL of saturated brine, dried over magnesium sulfate, magnesium sulfate was removed by suction filtration, and the solvent was distilled off under reduced pressure. Next, 350 mL of n-heptane was added to the crude crystals obtained, and the mixture was stirred at 50 ° C. for 1 hour, then returned to room temperature, and suction filtration was performed to obtain 64.8 g (yield 93.8percent) of the target compound.The dried 1 L reactor in dibenzofuran 52 g (247 mmol) under a stream of nitrogen and then dissolved in tetrahydrofuran, 520 mL at -78 °C stirred while 1.6M n-butyllithium 155 mL (247 mmol) was slowly added dropwise to. When the addition was complete, while maintaining the -78 °C and stirred for 1 hour. After raising to room temperature, trimethyl borate was added dropwise thereto 30.8 g (297 mmol) slowlyAnd the mixture was stirred for one hour. After the reaction was added dropwise a 2 N hydrochloric acid solution 200 mL at room temperature and stirred for 30 minutes. After extraction with ethyl acetate and water and the organic layer concentrated under reduced pressure, and recrystallized with methylene chloride and heptane to give the 24 g. (Yield 48.5percent)

Molecular Weight:212.01
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:212.0644743
Monoisotopic Mass:212.0644743
Topological Polar Surface Area:53.6
Heavy Atom Count:16
Complexity:259
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes