Phosphorus oxychloride → ethyl-7-chloro-2-methyl-1H-pyrrolo[3,2-b]pyridine-3-carboxylate

Participants

Reaction Steps

Ethyl 7-hydroxy-2-methyl-1H-pyrrolo[3,2-b]pyridine-3-carboxylate (44.0 g, 0.20 mol) is suspended in dry acetonitrile (400 mL). After addition of POCl3 (47 mL, 0.50 mol) the stirred reaction mixture is heated to reflux for 4 hours. The volatiles are removed under reduced pressure. The residue is suspended in ice-cold water (500 mL) and carefully neutralized to pH 8 by dropwise addition of 6N NaOH. Stirring is continued at ambient temperature over night. The pH is readjusted to 8, the product is filtered, washed with several small portions of water and dried in vacuum at 50° C. for 24 hours to yield the title compound as off-white solid.

Provenance & Evidence