Ethyl 6-aminoimidazo[1,2-a]pyridine-2-carboxylate

Synthesis

General procedure for the synthesis of ethyl 6-aminoimidazo[1,2-a]pyridine-2-carboxylate from ethyl 6-nitroimidazo[1,2-A]pyridine-2-carboxylate: 250 mg (1.01 mmol) of ethyl 6-nitroimidazo[1,2-a]pyridine-2-carboxylate was dissolved in 20 ml of ethanol at room temperature, and 30 mg of palladium (10% activated carbon) was added as a catalyst, the hydrogenation reaction was carried out and the reaction lasted for 5 hours at standard atmospheric pressure. After completion of the reaction, the reaction mixture was filtered through diatomaceous earth and the residue was washed with ethanol. The filtrates were combined, concentrated and dried under reduced pressure to give 215 mg of product (quantitative yield). The product was analyzed by LC/MS (Method 5): r = 1.40 mm; MS (ESIpos): m/z = 206 (M + H). 1H-NMR (400 MHz, DMSO-d5) data: δ [ppm] = 8.33 (s, 1H), 7.66 (s, 1H), 7.37 (d, 1H), 6.94 (dd, 1H). 5.11 (s, 2H), 4.26 (q, 2H), 1.29 (t, 3H).

References

[1] Patent: US2016/272637, 2016, A1. Location in patent: Paragraph 0500; 0501; 0502; 0503
[2] Heterocycles, 1994, vol. 38, # 7, p. 1527 - 1532
[3] Molecular Pharmaceutics, 2015, vol. 12, # 6, p. 1813 - 1835
[4] Patent: WO2015/185142, 2015, A1. Location in patent: Page/Page column 20; 21
[5] Patent: WO2008/100423, 2008, A1. Location in patent: Page/Page column 111