Phosphorus oxychloride → Ethyl 3-(2-fluorobenzyl)imidazo[1,5-a]pyridine-1-carboxylate

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Reaction Steps

2.72 g (8.60 mmol) of ethyl {[(2-fluorophenyl)acetyl]amino}(pyridin-2-yl)acetate from example 6A are introduced into 30 ml of 1,2-dichloroethane, and 4.81 ml (51.6 mmol) of phosphoryl chloride are added. The mixture is heated to reflux for 9 h and then concentrated in vacuo, and the residue is taken up in ethyl acetate. The solution is washed with saturated sodium carbonate solution, dried over sodium sulfate and purified by chromatography on silica gel (eluent: cyclohexane/ethyl acetate 2:1). 2.16 g (84% of theory) of the desired compound are obtained as a dark oil.

Provenance & Evidence