Synthesis
Step I: Synthesis of 2-amino-3-methyl-5-cyanopyridine
1. To a mixture of DMF and water (100:2, v/v, total 102 mL), 5-bromo-3-methylpyridin-2-amine (10 g, 53.47 mmol), zinc cyanide (3.77 g, 32.1 mmol), and 1,1'-bis(diphenylphosphino)ferrocene (3.56 g, 6.4 mmol) were added sequentially.
2. The mixture was degassed for 20 min.
3. tris(dibenzylideneacetone)dipalladium(0) (2.45 g, 2.67 mmol) was added and the reaction mixture was heated and stirred at 120 °C for 16 hours.
4. Upon completion of the reaction, the mixture was cooled to room temperature.
5. A mixture of saturated ammonium chloride solution, ammonium hydroxide and water (4:1:4 by volume, totaling 100 mL) was added.
6. cooled the formed slurry to 0 °C, added again a mixture of saturated ammonium chloride solution, ammonium hydroxide and water in the same ratio (100 mL) and stirred for 1 hour.
7. The solid product was collected by filtration through a Büchner funnel and dried under high vacuum to afford 2-amino-3-methyl-5-cyanopyridine 6.0 g (81% yield) as a tan solid.
MS (ES) m/z 134.1 (M + 1).
References
[1] Patent: WO2013/42139, 2013, A1. Location in patent: Page/Page column 83
[2] Patent: US2015/65464, 2015, A1. Location in patent: Paragraph 0368-0369
[3] European Journal of Medicinal Chemistry, 2014, vol. 84, p. 404 - 416
