Imidazo[1,2-a]pyridin-6-amine (9CI)

Synthesis

At room temperature and atmospheric pressure, 600 mg (3.68 mmol) of 6-nitroimidazo[1,2-a]pyridine was dissolved in 30 mL of ethanol and 60 mg of palladium/carbon catalyst (10% palladium loading) was added. The reaction system was placed in a hydrogen atmosphere and the reaction was stirred overnight. Upon completion of the reaction, the catalyst was removed by filtration through a diatomaceous earth pad and the filter cake was washed with ethanol. The filtrate and washings were combined and concentrated under reduced pressure to remove the solvent to give the crude product 6-aminoimidazo[1,2-a]pyridine, which can be used in subsequent reactions without further purification. Yield: 512 mg (quantitative yield). The product was analyzed by LC/MS [Method 5]: retention time Rt = 0.89 min; mass spectrum (ESI positive ion mode): m/z = 134 ([M+H]+). 1H-NMR (400 MHz, DMSO-d6) chemical shift δ [ppm]: 7.72-7.62 (m, 2H), 7.33 (d, 1H), 7.30 (d, 1H) , 6.80 (dd, 1H), 4.83 (s, 2H).

References

[1] Patent: US2017/275282, 2017, A1. Location in patent: Paragraph 0507-0509
[2] Patent: WO2009/122180, 2009, A1. Location in patent: Page/Page column 105
[3] Yakugaku Zasshi, 1949, vol. 69, p. 496
[4] Chem.Abstr., 1950, p. 4474
[5] Patent: US2016/272637, 2016, A1. Location in patent: Paragraph 0511; 0512; 0513; 0514