Hydrazine hydrate (1:1) → HCID 178434440, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of the above crude 1-(2-chloropyridin-3-yl)ethanone (XIII) in n-BuOH (512 L) was added 85% hydrazine hydrate (78 L, 1360 mol). The reaction was heated at refluxed (˜120° C.) for 48 hours. The reaction was cooled and evaporated under vacuum. The crude material was taken up in DCM (834 L) and washed with 2× aqueous 25% NaCl (214 L) by adding aqueous 25% NaCl, stirring for 50 min, allowing to stand for 50 min, separating the layers and then repeating. The organic layer was evaporated to produce 3-methyl-1H-pyrazolo[3,4-b]pyridine (XIV) as a solid (13.2 Kg, 99 mol, 94.1% purity, 36.3% assay yield for 3 steps). 1H NMR (DMSO-d6, 400 MHz) δ ppm 2.50 (s, 3H), 7.13 (dd, J=4.4 Hz, J=8 Hz, 1H), 8.19 (dd, J=1.2 Hz, J=8 Hz, 1H), 8.47 (dd, J=1.6 Hz, J=4.8 Hz, 1H), 13.18 (brs, 1H); ESIMS found C7H7N3 m/z 133.8 (M+H).

Provenance & Evidence