Hydrazine hydrate (1:1) → 4-Chloro-6-methyl-1H-pyrazolo[4,3-c]pyridine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,4-dichloro-6-methylpyridine-3-carbaldehyde (12 g, 63 mmol) in 1,2-dichloroethane (200 mL) was added hydrazine monohydrate (9.52 g, 0.190 mol), and the reaction mixture was heated at 80° C. for 18 hours. After removal of solvents in vacuo, the residue was suspended in water (150 mL) and stirred for 30 minutes. The resulting precipitate was collected by filtration and washed with petroleum ether (2×250 mL), then was suspended in chloroform (150 mL), stirred for 30 minutes and filtered. The chloroform suspension was repeated twice to afford the product as a white solid. Yield: 6.7 g, 40 mmol, 63%. LCMS m/z 168.1 [M+H+]. 1H NMR (400 MHz, DMSO-d6) δ 13.70 (br s, 1H), 8.21 (s, 1H), 7.38 (s, 1H), 2.52 (s, 3H).

Provenance & Evidence