Ethyl orthoformate → tert-butyl 3-(6-bromo-1H-imidazo[4,5-c]pyridin-1-yl)piperidine-1-carboxylate

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Reaction Steps

A mixture of tert-butyl 3-((5-amino-2-bromopyridin-4-yl)amino)piperidine-1-carboxylate (1.1 g, 3.0 mmol, 1.0 eq) in CH(OCH2CH3)3 (214 mg, 30 mmol, 10 eq) was refluxed for 40 h. Then the residual CH(OCH2CH3)3 was removed in vacuum and the crude product was purified by silica gel column chromatography with EtOAc in PE (½ v/v) to give the title compound (0.8 g, 70%) as yellow oil. 1H NMR (400 MHz, CDCl3) δ: 8.87 (s, 1H), 8.06 (s, 1H), 7.62 (s, 1H), 4.30-4.28 (m, 2H), 4.02-4.00 (m, 1H), 3.27-3.22 (m, 1H), 3.09-3.03 (m, 1H), 2.31-2.30 (m, 1H), 2.13-2.10 (m, 1H), 1.88-1.85 (m, 1H), 1.74-1.71 (m, 1H), 1.50 (s, 9H). ESI-MS (M+H+): 381.0.

Provenance & Evidence