1,3-dibromo-2-ethylbenzene(WX191512) synthesis

Yield:41053-30-9 79.9%

Reaction Conditions:

in tetrahydrofuran at -70; for 2 h;Inert atmosphere;

Steps:

30

A three necked round-bottom flask was purged with argon and then filled with dry THF (6OmL), 1, 3-dibromo benzene (9.5 g, 40.27mmol) and ethyl iodide (8.8 g, 56.38mmol). The mixture was cooled to -78 ⁰C and LDA [made from 8 mL of JPr₂NH and 10 mL of BuLi (2.5M in hexane) in 4OmL of THF] was added slowly at -7O ⁰C. After stirring for 2 hr the reaction was poured into 100 mL of sat. aq. NH₄CI solution and stirred vigorously for 20 min, extracted with DCM (2 * 100 mL). The organic layer was evaporated to give the crude product, which was purified by column chromatography with hexane to give 1,3-Dibromo-2-ethylbenzene (8.5g, 79.9%). δH (CDCI₃, 400 MHz): 7.76-7.78 (2H, m), 6.86-6.90 (1H, m), 2.89-3.01 (2H₁ q), 1.12 (3H₁ 1) ppm. MS (ES⁺): C₈H₈Br₂ requires 264; found 265 (M+H⁺).

References:

WO2010/145202,2010,A1 Location in patent:Page/Page column 39-40