Chloroacetaldehyde → Imidazo[1,2-a]pyridin-8-amine

Participants

Reaction Steps

To a solution of 50% aqueous chloroacetaldehyde (4.14 mL, 32.6 mmol) were added sodium bicarbonate (3.19 g, 40.0 mmol) and 2,3-diaminopyridine (3.56 g, 32.6 mmol). The reaction mixture was stirred at rt overnight, then diluted with saturated aqueous NaCl (100 mL) and extracted with n-butanol (3×200 mL). The organic layers were combined, dried (MgSO4), and concentrated. The crude residue was purified (FCC, 2 N NH3 in MeOH/DCM) to give imidazo[1,2-a]pyridin-8-ylamine (2.18 g, 51%). MS (ESI+): calcd for C7H7N3 m/z 133.06, found 134.1 (M+H)+. 1H NMR (d6-DMSO): 7.79-7.75 (m, 2H), 7.40 (d, J=1.1, 1H), 6.60 (s, 1H), 6.21 (dd, J=7.3, 1.1, 1H), 5.53 (br s, 2H).

Provenance & Evidence