Synthesis
2-Bromo-5-chloro-3-methylpyridine (45 g, 218 mmol) and zinc cyanide (8.30 mL, 131 mmol) were added to a tris(dibenzylideneacetone)dipalladium(0) (4.99 g, 5.45 mmol) and 1,1'-bis(diphenylphosphino)ferrocene (6.04 g, 10.90 mmol) dimethylacetamide (40 mL ) solution. The mixture was heated to 110 °C and reacted for 4 hours. After completion of the reaction, it was cooled to room temperature, the reaction mixture was diluted with water and extracted with ethyl acetate. The organic phases were combined and concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography using an ISCO system eluting with a 0-60% ethyl acetate/hexane gradient to afford the target product 2-cyano-3-methyl-5-chloropyridine (25.4 g, 166 mmol, 76% yield). The product was detected by LC/MS (ESI+) with m/z = 153.1 ([M+H]+).
References
[1] Patent: WO2014/138484, 2014, A1. Location in patent: Page/Page column 143
[2] Patent: US2015/38497, 2015, A1. Location in patent: Paragraph 0993
[3] Patent: WO2016/22724, 2016, A1. Location in patent: Page/Page column 294; 295
