Hexane → 3-Methoxy-4-[(3-phenylpropanoyl)amino]phenylboronic acid

Temperatur

-78 °C

A solution of N1-(4-bromo-2-methoxyphenyl)-3-phenylpropanamide (1.004 g, 3 mmol) in anhydrous tetrahydrofuran (30 mL) at −78° C. was treated with a solution of 1.6 M n-butyl lithium in hexane (4.7 mL, 7.5 mmol). The reaction mixture was stirred at −78° C. for 40 min. Tri-isopropyl borate(1.05 mL, 4.5 mmol) was added to this reaction mixture, and stirred at −78° C. for 20 min. The acetone/dry ice bath was removed. The reaction mixture was stirred for 4 h at room temperature. The reaction mixture was quenched with 2.5 N hydrochloric acid solution (30 mL). The organic layer was removed under reduced pressure. Ethyl acetate was added to the acidic aqueous layer. The layers were partitioned, and the aqueous layer was extracted with ethyl acetate (250 mL). The combined organic layer was washed with water and brine, dried over magnesium sulfate, filtered and evaporated under reduced pressure. The crude product was purified by flash chromatography on silica gel, using 1:1 dichloromethane:ethyl acetate as eluent. The gradient was changed to 15% methanol in dichloromethane to remove the baseline product to give 0.209 g (23%) of 3-methoxy-4-[(3-phenylpropanoyl)amino]phenylboronic acid. 1H NMR (DMSO-d6, 400 MHz) δ 9.08 (s, 1H), 7.89-7.95 (m, 3H), 7.45-7.42 (s, 1H), 7.35-7.16 (m, 5H), 3.82 (s, 3H), 2.91-2.81 (m, 2H), 2.74-2.70 (s, 2H); HPLC Waters 2690 Alliance HPLC (Symmetry Shield RP18 3.5 μm, 2.1×50 mm; 5%-95% acetonitrile-0.1 M ammonium acetate over 15 min, 0.5 mL/min) Rt 5.389 min (95%).

1. stirringstirred at −78° C. for 20 min
2. customThe acetone/dry ice bath was removed
3. stirringThe reaction mixture was stirred for 4 h at room temperature
4. customThe reaction mixture was quenched with 2.5 N hydrochloric acid solution (30 mL)
5. customThe organic layer was removed under reduced pressure
6. additionEthyl acetate was added to the acidic aqueous layer
7. customThe layers were partitioned
8. extractionthe aqueous layer was extracted with ethyl acetate (250 mL)
9. washThe combined organic layer was washed with water and brine
10. dry with materialdried over magnesium sulfate
11. filtrationfiltered
12. customevaporated under reduced pressure
13. customThe crude product was purified by flash chromatography on silica gel
14. customto remove the baseline product

ORD-Eintrag

ord-61089c3c13b64ec89d80a6ddfc1d4e1a

Quelldatensatz

uspto-grants-2003_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06660744B1