Water → 4-Methoxyindole-3-aldehyde

Participants

Reaction Conditions

Reaction Steps

Add phosphorus oxychloride (1.1 eq.) with vigorous stirring to DMF (cooled in an ice bath). After the addition is complete, allow to stir in the ice bath for ˜10 minutes, then add a solution of 4-methoxy-1H-indole (5 g) in anhydrous DMF with vigorous stirring. Allow to stir at 0° C. After 1 hour, warm to room temperature. After 16 hours, carefully add 4 eq. of 2N NaOH with vigorous stirring. Heat to about 80° C. and then cool. Pour the reaction mixture into cold water with vigorous stirring to give a solid. Collect the solid by filtration and dry in a vacuum oven at room temperature to give the title compound. Acidify the filtrate and extract with EtOAc. Combine the organic layers and wash with 50% brine. Collect the organic layer, dry (MgSO4) filter, and remove the solvent to give the title compound as a light purple solid. Total yield of the title compound is 5.44 g: MS (ES+): m/z 175 (M+H)+, 160 (M−CH3)+; (ES−): m/z 174 (M−H)−.

Provenance & Evidence