Synthesis
GENERAL METHOD: 2-chloro-5-nitropyridine (50 mmol), morpholine (100 mmol), and K2CO3 (100 mmol) were dissolved in THF (50 mL), and the reaction was stirred at 80 °C for 4 hours. Upon completion of the reaction, the mixture was concentrated to 20 mL and subsequently poured into water (100 mL) to precipitate a yellow solid precipitate. After filtration, washing with pure water and drying, the target compound 3a was obtained.Compound 3b was prepared by the same method. Compounds 3a-3b (20 mmol) were mixed with Pd/C (20%, 500 mg) in methanol and subjected to hydrogenation reaction for 12 h at room temperature. At the end of the reaction, the reaction solution was filtered and concentrated to obtain the target compounds 4a-4b.
References
[1] Chinese Chemical Letters, 2016, vol. 27, # 1, p. 1 - 6
[2] Patent: WO2005/28452, 2005, A1. Location in patent: Page/Page column 94
[3] Patent: WO2006/100588, 2006, A1. Location in patent: Page/Page column 63
[4] Journal of Medicinal Chemistry, 1994, vol. 37, # 1, p. 18 - 25
[5] Patent: US2012/258951, 2012, A1. Location in patent: Page/Page column 77
