Ethyl 2-chloroacetoacetate → Ethyl 8-(benzyloxy)-2-methylimidazo[1,2-A]pyridine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

25 g of 2-amino-3-benzyloxypyridine (124.8 mmol, 1 equivalent) were dissolved in 781 ml of ethanol, and 102.7 g of ethyl 2-chloroacetoacetate (624.2 mmol, 5 equivalents) and 15 g of 4 Å molecular sieve were added. The mixture was heated at reflux for 2 d (bath temperature 100° C.). The mixture was then concentrated and excess ethyl 2-chloroacetoacetate was distilled off on a rotary evaporator with dry ice-cooling. The residue was purified by silica gel chromatography (mobile phase cyclohexane:ethyl acetate 9:1, 4:1). This gave 20.81 g of the title compound (54% of theory).

Provenance & Evidence