Acetic Acid → 5-chloro-1H-pyrrolo(2,3-b)pyridine-3-carbaldehyde

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]2[C:8](=[N:9][CH:10]=1)[NH:7][CH:6]=[CH:5]2.C1N2CN3CN(C2)CN1C3.[C:21](O)(=[O:23])C>O>[Cl:1][C:2]1[CH:3]=[C:4]2[C:8](=[N:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[CH:21]=[O:23]

Participants

Procedure

To a solution of 5-chloro-7-azaindole (0.50 g, 3.3 mmol) in acetic acid (5.0 mL), hexamethylenetetramine (0.69 g, 4.9 mmol) was added at ambient temperature. The mixture was refluxed for 8 h. Cooled to ambient temperature, the reaction mixture was diluted with water, extracted with ethyl acetate for 2 times. The organic layer was washed with water and brine, dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel(hexane/ethyl acetate) to afford 5-chloro-7-azaindole-3-carboxaldehyde as solid (0.13 g, y. 22%).