AKOS BRN-1022 synthesis

Yield:900174-62-1 57%

Reaction Conditions:

Stage #1: 1-bromo-4-chloro-3-ethoxybenzenewith n-butyllithium in tetrahydrofuran;hexane at -78; for 0.666667 h;
Stage #2: with Triisopropyl borate in tetrahydrofuran;hexane at -78; for 18 h;
Stage #3: with hydrogenchloride;water in tetrahydrofuran;hexane;

Steps:

15.15B

To a solution of Intermediate 15A (3.8 g, 16 mmol) in THF (20 mL) at -78° C. was added n-BuLi (1.6 M in hexanes, 13.6 mL, 21.8 mmol). The mixture was stirred at -78° C. for 40 min before triisopropyl borate (7.43 mL, 32 mmol) was added. The reaction was left stirring from -78° C. to rt over 18 h. It was quenched with 1.0 N HCl (50 mL), extracted with EtOAc, washed with brine and dried over Na₂SO₄. The crude residue was purified by flash column chromatography (CH₂Cl₂: EtOAc:MeOH=50:50:1) to give 1.85 g (57%) of Intermediate 15B as a white solid. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.53 (t, J=7.03 Hz, 3 H) 4.23 (d, J=7.03 Hz, 2 H) 7.48 (d, J=7.91 Hz, 1 H) 7.66 (d, J=6.15 Hz, 2 H).

References:

US2007/3539,2007,A1 Location in patent:Page/Page column 43-44