Acetic Anhydride → 1,2-Dimethyl-1H-imidazo[4,5-c]pyridine

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Reaction Steps

The solution of N4-methylpyridine-3,4-diamine (2.5 g, 20.3 mmol) in acetic anhydride (25 mL) was refluxed overnight. Then acetic anhydride was evaporated under reduced pressure and 1 N hydrochloride acid was added. Then the mixture was extracted with dichloromethane (50 mL×3). The aqueous layer was neutralized with sodium bicarbonate, and extracted with dichloromethane (50 mL×3). The organic layers were concentrated to give the title compound (1.9 g, yield 64%). LC-MS (ESI) m/z: 148 (M+1)+. 1H-NMR (400 MHz, CDCl3) δ (ppm): 2.64 (s, 3H), 3.74 (s, 3H), 7.23-7.24 (d, J=5.2 Hz, 1H), 8.39-8.41 (d, J=5.2 Hz, 1H), 8.98 (s, 1H).

Provenance & Evidence