(4-Hydroxyphenyl)boronic acid

off-white to light brown powder

17 g (0.1 mol) of 4-bromophenol, 16.5 g (0.11 mol) of dimethyl t-butylchlorosilane, 30 ml of DMF, 20 ml of triethylamine and 0.1 g of DMAP were added to a 100 ml three-necked flask.Room temperature reaction for 24 hours.After completion of the reaction, equal volume of water and petroleum ether were added, the layers were allowed to stand, the aqueous phase was removed, washed with water until neutral, and the solvent was removed by steaming to give a colorless oily liquid.In a 250 ml three-necked flask, 2.6 g (0.11 mol) of Mg chips, a small particle of crystalline iodine and 50 ml of tetrahydrofuran were added successively.A mixture of 28.70 g (0.1 mol) of 1-bromo-4 - [(1, 1-dimethylethyl) dimethylsiloxy] -benzene and 20 ml of tetrahydrofuran was prepared.A small amount of the above solution is added to initiate a Grignard reaction (if not, slightly heated to initiate the reaction), and then the remaining solution is added dropwise with stirring.Control the rate of drop, with ice water bath temperature control, keep the reaction temperature below 35 .After the drop was added, the mixture was stirred at room temperature for 1 hour.Acetone-liquid nitrogen bath The solution was cooled to -65 ° C and 11.44 g (0.11 mol) of trimethyl borate in 60 ml of tetrahydrofuran was added dropwise at a temperature of -60 ° C.After the drop, stir the natural temperature to -30 , acidified with concentrated hydrochloric acid to acidic (PH = 1).The reaction solution was transferred to a separatory funnel, 100 ml of ethyl acetate was added and the mixture was allowed to stand. The organic phase was washed with saturated brine to neutral. The aqueous phase was separated and the organic phase was transferred to a 250 ml three-necked flask. 28.71 g mol) tetrabutylammonium fluoride, room temperature reaction for 24 hours, the reaction is completed.Transfer to the separatory funnel, with saturated brine to neutral, the water phase, the organic phase steaming to remove the solvent, recrystallization from petroleum ether to obtain a white solid.General procedure: In a flask containing the appropriate potassiumorganotrifluoroborate (0.5 mmol) in distilled water(1 mL) was added montmorillonite K10 (150percent m/m). Themixture was stirred for the time indicated in Scheme 1at room temperature. After this period, the mixture wasextracted with EtOAc (3 × 10 mL) and the organic phasewas washed with water (2 × 15 mL). The organic phasewas dried over anhydrous MgSO4, filtered and the solventwas removed in vacuo to yield the corresponding boronicacids 2a-o.Under nitrogen, 1.5 kg of 4-methoxyphenylboronic acid was added to a 30 L glass reactor, 20 liters of toluene and 1.17 kg of acetyl chloride was added after the reaction mixture was cooled to -10 ~ 0 , Stir for 1 hour. Begin adding 267 g of anhydrous aluminum trichloride in batches, after the addition is completed, the temperature is raised to 80 ° C., and the mixture is kept under stirring until TLC shows that the reaction of raw materials is complete. The process takes about 3 to 5 hours. During this process, the solid of the reaction mixture gradually dissolves, followed by gradual solid precipitation. Add 2M aqueous sodium hydroxide solution quench, adjust PH = 11-12 so far. At this point the organic layer is separated and discarded. The aqueous layer was added 6M aqueous hydrochloric acid to adjust PH = 2, 15 liters of ethyl acetate extraction twice, the organic layer was combined, washed with saturated brine, the organic layer spin dry, beating with acetone / n-heptane to obtain white crystalline solid p-hydroxybenzene boronic acid 1.01 kg, 73percent yield, HPLCAmount: 99.1percent.

suzuki reaction

Molecular Weight:137.93
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:138.0488242
Monoisotopic Mass:138.0488242
Topological Polar Surface Area:60.7
Heavy Atom Count:10
Complexity:99.2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes