反应详情

To a solution of 1,3-dibromo-2-methylbenzene (6.57 g) in dry THF (100 mL), t-BuLi solution (1.5 M in pentane, 17 mL) was added dropwise at −80° C. Then reaction mixture was stirred between −76˜−78° C. for 2 h. Then the mixture was cooled to below −80° C. and dry ice was added after which the mixture was warmed to room temperature naturally. Solvent was removed, 5% NaOH solution (40 mL) added and the aqueous solution was washed with CH2Cl2 (10 mL×2). Then the aqueous layer was acidified with concentrated HCl to pH=1 and extracted with EtOAc (100 mL×2). The combined organic extracts were dried over anhydrous Na2SO4. After removing the solvent, the residue was purified by silica column chomatography, (eluted with petrol. ether: EtOAc=8:1 to 1:1), to obtain 3.58 g of the product. Yield: 63.4%. 1H NMR (400 MHz, CDCl3) δ 2.73 (s, 3H), 7.15 (t, J=8.0 Hz, 1H), 7.77 (dd, J=8.0 Hz, J=1.2 Hz, 1H), 7.94 (dd, J=8.0 Hz, J=1.2 Hz, 1H).

1. customThen reaction mixture
2. temperatureThen the mixture was cooled to below −80° C.
3. customSolvent was removed
4. addition5% NaOH solution (40 mL) added
5. washthe aqueous solution was washed with CH2Cl2 (10 mL×2)
6. extractionextracted with EtOAc (100 mL×2)
7. dry with materialThe combined organic extracts were dried over anhydrous Na2SO4
8. customAfter removing the solvent
9. customthe residue was purified by silica column chomatography, (eluted with petrol. ether: EtOAc=8:1 to 1:1),