Phosphorus oxychloride → ETHYL6-CHLORO-1H-PYRAZOLO[3,4-B]PYRIDINE-4-CARBOXYLATE

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-hydroxy-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester (116.4 g, 0.562 mol) and phosphorus oxychloride (500 mL) was heated at 110° C. for 6 hours then cooled to room temperature before being evaporated under reduced pressure. The residue was taken up in EtOAc and the precipitate filtered. The filtrate was neutralized using triethylamine (500 mL) and the resulting salt filtered. The filtrate was concentrated under vacuum and the residue subjected to silica gel column chromatography using a 9/1 mixture of toluene/EtOAc to afford the title compound as a yellow solid (26.3 g, 21%).

Provenance & Evidence