Synthesis
An anhydrous dichloromethane solution of valeroyl chloride (0.32 mL, 2.57 mmol) was slowly added dropwise to an anhydrous dichloromethane suspension of 2-amino-6-chloropyridine (0.30 g, 2.33 mmol) and triethylamine (0.41 mL, 2.92 mmol) at 0 °C. The reaction mixture was kept stirred at 0 °C for 50 min, followed by gradual warming to room temperature to continue the reaction. After 5 hours of reaction, the mixture was poured into water and the organic phase was separated. The aqueous layer was extracted with dichloromethane and the combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by Combiflash fast chromatography system using 0-15% ethyl acetate/hexane gradient elution to afford N-(6-chloropyridin-2-yl)-2,2-dimethylpropionamide (0.48 g, 2.28 mmol, 98% yield) as a white solid.
References
[1] Patent: WO2011/50245, 2011, A1. Location in patent: Page/Page column 118
[2] Patent: WO2008/128942, 2008, A1. Location in patent: Page/Page column 33
[3] Journal of Medicinal Chemistry, 2000, vol. 43, # 16, p. 3134 - 3147
[4] Patent: WO2017/211759, 2017, A1. Location in patent: Page/Page column 92
[5] Organic Process Research and Development, 2009, vol. 13, # 3, p. 555 - 566
