Hydrazine hydrate (1:1) → 1H-pyrazolo(3,4-b)pyridine

Participants

Reaction Steps

A solution of 2-chloropyridine-3-carbaldehyde (20 g, 141 mmol) and hydrazine monohydrate (60% in water, 113 g, 2.1 mol) in 140 mL water was heated at 100° C. for 72 hours. The reaction mixture was cooled to room temperature and diluted with 200 mL of EtOAc. The aqueous layer was separated and extracted with EtOAc (3×). The combined organics were dried over MgSO4, filtered and concentrated in vacuo to give a light orange solid which was crystallized from hexanes to give the title compound as an off-white solid. 1H NMR (400 MHz, CH3CN-d3): δ 11.56 (s, 1H); 8.51 (dd, J=4.52, 1.56 Hz, 1H); 8.17 (dd, J=8.05, 1.58 Hz, 1H); 8.05 (s, 1H); 7.17 (dd, J=8.05, 4.51 Hz, 1H).

Provenance & Evidence