Dimethylformamide → 4-Methoxyindole-3-aldehyde

Reaction equation

CN(C=O)C.[C:6](Cl)(=[O:10])[C:7](Cl)=O.[CH3:12][O:13][C:14]1[CH:22]=[CH:21][CH:20]=[C:19]2[C:15]=1C=[CH:17][NH:18]2>ClC(Cl)C>[CH3:12][O:13][C:14]1[CH:22]=[CH:21][CH:20]=[C:19]2[C:15]=1[C:7]([CH:6]=[O:10])=[CH:17][NH:18]2

Participants

Procedure

A solution of dry DMF (0.75 g) in 50 ml dichloroethane was cooled to 0° C. and placed under nitrogen. Oxalyl chloride (1.03 g) dissolved in dichloroethane (5 ml) was added dropwise with stirring. The solution was stirred until no more bubbling was observed (about 15-20 m). 4-Methoxyindole (1.0 g, 6.7 mmole) was added to the solution as a solid and the reaction mixture was stirred at room temperature for four hours. The reaction was quenched by careful addition of 10% sodium carbonate solution. The two phase mixture was stirred at room temperature for 2 hours. The layers were separated and the aqueous layer was extracted with methylene chloride, and the combined organic extracts were dried and evaporated to dryness. The crude residue was passed through a short silica gel column, eluting with 3:7 ethyl acetate:hexane to 1:1 ethyl acetate:hexane to yield 1.13 g (95%) of 4-methoxy-1H-indole-3-carbaldehyde.