tert-butyl 4-(6-aMinopyridin-3-yl)piperidine-1-carboxylate

Synthesis

In a 500 mL round-bottomed flask, tert-butyl 4-(6-nitropyridin-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate (4.9 g, 16.0 mmol, 1.00 equiv.) was dissolved in a solvent mixture of ethanol (300 mL) and ethyl acetate (75 mL) and palladium carbon (1.32 g, 1.24 mmol, 0.0773 equiv.) was added. The reaction mixture was displaced twice with hydrogen and then stirred overnight under a hydrogen atmosphere (using a hydrogen balloon). The completion of the reaction was confirmed by LC/MS analysis. The reaction mixture was purged with nitrogen and filtered through a diatomaceous earth pad, which was washed several times with ethyl acetate. The colorless filtrate and washings were combined, dichloromethane was added and the solution was evaporated to dryness. Dichloromethane was added again and the solution was concentrated under vacuum to give the target product tert-butyl 4-(6-aminopyridin-3-yl)piperidine-1-carboxylate in quantitative yield. (M + H)+ = 278 m/z.

References

[1] Patent: WO2013/24078, 2013, A1. Location in patent: Page/Page column 57; 58
[2] Patent: CN106608879, 2017, A. Location in patent: Paragraph 0268-0269; 0273-0274
[3] Patent: WO2014/83026, 2014, A1. Location in patent: Page/Page column 26; 47-48
[4] Patent: CN105622638, 2016, A. Location in patent: Paragraph 0181
[5] Patent: US2018/297995, 2018, A1. Location in patent: Paragraph 0046; 0051; 0052