Electric Literature of 1996-29-8,Some common heterocyclic compound, 1996-29-8, name is 1-Bromo-4-chloro-2-fluorobenzene, molecular formula is C6H3BrClF, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
n-Butyllithium (2.1 M in hexane; 68 ml, 149 mmol) was added dropwise to a stirred solution of diisopropylamine (15 g, 149 mmol) in anhydrous tetrahydrofuran (700 ml) at -78C under a nitrogen atmosphere. Once the addition was complete the reaction mixture was allowed to warm to 00C, cooled to -78C and a solution of 1-bromo-4- chloro-2-fluorobenzene (25 g, 119 mmol) in anhydrous tetrahydrofuran (60 ml) was added dropwise. The mixture was allowed to warm to -200C, cooled to -78C and a solution of trimethylborate (15 g, 143 mmol) in anhydrous tetrahydrofuran (30 ml) added dropwise. The reaction mixture was allowed to warm to -200C and stirred at that temperature for 30 minutes, then cooled to -78C and peracetic acid (80 ml) added dropwise. The mixture was allowed to warm to ambient temperature and stirred overnight under nitrogen. Water (1 I) was added and the resulting mixture extracted with ethyl acetate (3 x 500 ml). The combined organic extracts were washed with water and brine, dried over sodium sulphate, filtered and evaporated under reduced pressure. The residue was purified by column chromatography on silica using 2% ethyl acetate in hexane as eluent to provide 3-bromo-6-chloro-2-fluorophenol (13.8 g, 51%).
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 1-Bromo-4-chloro-2-fluorobenzene, its application will become more common.
Reference:
Patent; SYNGENTA LIMITED; WHITTINGHAM, William Guy; WINN, Caroline Louise; GLITHRO, Harry; ASPINALL, Mary Bernadette; SCREPANTI, Claudio; WO2010/125332; (2010); A1;,
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