Dimethylformamide → 1-benzyl-2,3-dihydroindole-5-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

Into a 1,000 mλ reaction flask equipped with a thermometer, a stirrer, a condenser and a dropping funnel, 209 g (1.0 mol) of 1-benzylindoline and 365.5 g (5.0 mols) of N,N-dimethylformamide (DMF) were charged, and the temperature was raised to a liquid temperature of from 30 to 40° C. Then, while stirring at the same temperature, 161.0 g (1.05 mols) of phosphorus oxychloride was dropwise added thereto over a period of about two hours from the dropping funnel. After completion of the dropwise addition, stirring was continued for three hours at from 80 to 100° C. After completion of the reaction, the reaction solution was cooled to room temperature and put into 1 kg of ice water. At a temperature of from 30 to 40° C., a 24% sodium hydroxide aqueous solution was dropwise added thereto to bring the liquid alkaline, whereby the precipitated solid was collected by filtration, washed with water and dried to obtain 230.2 g (yield: 97%) of 1-benzyl-5-formylindoline as a slightly yellow powder.

Provenance & Evidence