Synthesis
Step 1: Synthesis of 1-(6-bromopyridin-3-yl)ethanone
To a stirred solution of 2,5-dibromopyridine (1.0 g, 4.219 mmol) in ether (10 mL) was slowly added n-butyllithium (2.0 mL, 5.0 mmol, 2.5 M hexane solution) at -78 °C and the reaction was carried out under nitrogen protection. After keeping stirring at -78 °C for 1 h, N,N-dimethylacetamide (0.58 g, 6.3 mmol) was added dropwise and stirring was continued at -78 °C for 4 h. The reaction was carried out under nitrogen protection. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction was quenched with ice water and subsequently partitioned between saturated ammonium chloride (NH4Cl) solution and ethyl acetate (EtOAc). The organic layer was washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 1-(6-bromopyridin-3-yl)ethanone (0.4 g, 47% yield) as a yellow solid. Mass spectrometry (MS) showed a molecular ion peak m/z 200.1 [M++1].
References
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[3] Bioorganic and Medicinal Chemistry, 2010, vol. 18, # 11, p. 3860 - 3874
[4] Patent: US2017/291894, 2017, A1. Location in patent: Paragraph 0428
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