Chloroacetaldehyde → 6-Chloroimidazo(1,2-a)pyridine

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Reaction Steps

To a solution of 50% aq. chloroacetaldehyde (1.1 eq, 291 mmol, 37 ml) in ethanol (700 ml) is added 3-amino-6-chloro-pyridine (1 eq, 264 mmol, 34 g) at room temperature. The reaction mixture is refluxed for 3 hours. The solvent is removed in vacuo and the crude product is dissolved in water (400 ml). The aqueous solution is treated with sodium bicarbonate to pH=8 and extracted with dcm (3×250 ml), the organic layer is dried (MgSO4) and evaporated to give a brown solid (39.2 g) 6-chloro-imidazo[1,2-a]pyridine; [M+H]+153(155)

Provenance & Evidence