Synthesis
2,5-Dibromopyridine (I-1-1) 8 g (33.7 mmol) was stirred with 337 mL of toluene at -40 °C in a nitrogen atmosphere. After stirring for 40 min, 21.4 mL (1.02 eq.) of a hexane solution of 1.6 M n-butyllithium was added slowly and dropwise to the reaction system, followed by 9.38 mL (3.0 eq.) of N,N-dimethylacetamide (DMAc). The reaction mixture was stirred and gradually warmed to 20 °C. Upon completion of the reaction, the reaction was quenched by the addition of saturated aqueous ammonium chloride, followed by extraction and liquid-liquid separation. The organic phase was purified by silica gel column chromatography to afford the target product 2-acetyl-5-bromopyridine (Compound I-1-2) 6.74 g in 100% yield as a white solid.
References
[1] Patent: JP2016/56276, 2016, A. Location in patent: Paragraph 0111; 0112
[2] Tetrahedron, 2008, vol. 64, # 17, p. 3794 - 3801
[3] Dalton Transactions, 2011, vol. 40, # 29, p. 7534 - 7540
[4] Journal of the American Chemical Society, 2016, vol. 138, # 38, p. 12643 - 12647
[5] Patent: WO2015/27021, 2015, A1. Location in patent: Page/Page column 78
