Chloroacetaldehyde → Ethyl 5-amino-6-chloroimidazo[1,2-a]pyridine-8-carboxylate

Participants

Reaction Steps

To a solution of ethyl 2-amino-5-chloro-6-[(2,2-dimethylpropanoyl)amino]nicotinate (Example 1, METHOD A, Step 2, 685 mg, 2.12 mmol) in ethanol (10 mL) was added 50% aqueous chloroacetaldehyde (430 μL, 3.4 mmol), and the mixture was refluxed with stirring overnight. The mixture was treated with charcoal and filtered. The filtrate was dry-loaded onto silica gel and chromatographed on a column of silica gel eluting with dichloromethane/methanol/25% aqueous ammonia (97:3:1 to 95:5:0.5) to give 220 mg (40%) of the title compound as a white solid.

Provenance & Evidence