Chloroacetaldehyde → Methyl imidazo(1,2-a)pyridine-7-carboxylate

참여 물질

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To a solution of Methyl 2-aminopyridine-4-carboxylate (10.0 g, 66 mmol, 1.0 equiv) in EtOH (150 ml) was added NaHCO3 (11.1 g, 132 mmol, 2.0 equiv) followed by chloroacetaldehyde (50% by weight in water, 13.0 ml, 99 mmol, 1.5 equiv). The mixture was refluxed for 2 h. Solvents were removed under reduced pressure and the crude mixture was partitioned between water and EtOAc. The resulting precipitate was washed with Et2O and recrystallised from MeOH/Et2O to afford 8.4 g of product. 1H NMR (400 MHz, DMSO-d6): 8.66 (1H, d), 8.16 (2H, s), 7.80 (1H, s), 7.33 (1H, d), 3.90 (3H, s). MS: [M+H]+ 177.

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