Isopropanol → ethyl 1-benzyl-6-chloro-1H-pyrazolo[3,4-b]pyridine-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

Phosphoryl trichloride (74 mL/0.81 mol) is added dropwise to a solution of ethyl 1-benzyl-6-hydroxy-1H-pyrazolo[3,4-b]pyridine-4-carboxylate [CAS 74439-45-5] (40.0 g/0.135 mol) in 450 mL of DMF at 0° C. under nitrogen. The reaction medium is stirred at 80° C. for 24 hours so as to give a dark brown solution. It is then run into a mixture of ice-cold water, and extracted with EtOAc. The organic phase is washed with water, dried with sodium sulphate, filtered and concentrated to dryness. The solid obtained is taken up with isopropanol, filtered, washed with diisopropyl ether and oven-dried to give 30.6 g of a yellow powder (yield: 72%).

Provenance & Evidence