3-Thienylboronic acid

white to light yellow crystal powder

General procedure: Triphenylphosphene (0.131 g, 0.5 mmol, 20 mol percent), p-iodoanisol (0.585 g, 2.5 mmol), and triethylamine (1.78 mL, 12.5 mmol) were added to a 50 mL round-bottomed flask equipped with a sidearm, condenser, and stir bar. This solution was then degassed by alternating vacuum and argon three times. Palladium dichloride (0.023 g, 0.13 mmol, 5 mol percent) was then added under positive argon pressure. After stirring at room temperature for 15 min, diisopropylaminoborane (5 mL, 1 M solution in THF, 5 mmol) was added and the reaction mixture was degassed again by alternating vacuum and argon three times. The reaction solution was then heated to reflux. After 12 h of reflux the reaction was cooled to 0 °C and 6 mL of methanol was added through the condenser slowly (Caution: exothermic reaction with evolution of hydrogen). After 15 min of stirring all the solvent was removed under reduced pressure to yield a black solid. This solid was dissolved with sodium hydroxide (3 M, 8 mL) and subsequently washed with hexanes (3.x.10 mL). The aqueous layer was then cooled to 0 °C (ice bath) and acidified to pH <=1 with concentrated HCl, with the boronic acid usually precipitating out as a white solid. The aqueous fraction was then extracted with diethyl ether (3.x.10 mL). The organic fractions were combined, dried with magnesium sulfate and filtered. The solvent was then removed under reduced pressure yielding a white solid.Preparation of Compound 1-1After 3-bormothiophene (50 g, 306 mmol) was dissolved in THF (300 mL) and toluen (1, 200 mL), the mixture was cooled to -78 °C, and n-BuLi (150 mL, 2.5M in hexane, 367 mmol) was added thereto. After stirring the mixture for 1 hour, triisopropylborate (112 mL, 490 mmol) was added while maintaining temperature at -78 °C. The mixture was stirred for 10 minutes. Upon completion of the reaction, HA solution of 3-bromothiophene (30.67 mmol=5 g) and tri-isopropyl borate (40 mmol=8.33 g or 9 ml) in 30 ml THF was treated with n-BuLi (2.5M in hexanes, 40 mmol 16 ml) at -78° C. over a period of 20 minutes. The resulting solution was stirred at -78° C. for an hour, and was then warmed up to -20° C. slowly and quenched slowly using 2N HCl. The mixture was then warmed to room temperature, diluted with ethyl acetated and brine. The organic layer was separated, concentrated and dried in vacuo. The white crude residue was re-crystallized using hot water to give 2.25 g of pure thiophene-3-boronic acid (17.58 mmol, 57.3percent) with m.p at 126-128° C. [128-130° C. reported] (see Collis, G. E.; Burrell, A. K.; Scott, S. M.; Officer, D. L., J. Org. Chem. 2003, 68, (23), 8974-8983).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.A. A.

suzuki reaction

Molecular Weight:127.96
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:128.0103307
Monoisotopic Mass:128.0103307
Topological Polar Surface Area:68.7
Heavy Atom Count:8
Complexity:78.4
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes