Dimethylformamide → 2-chloro-1H-indole-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

POCl3 (100 ml) was added dropwise to a mixture of dry DMF (100 ml) and dichloromethane (100 ml) kept at 0° C. Indolone (50 g) dissolved in dichloromethane (200 ml) and pyridine (50 ml) was added dropwise at 0° C. over a period of 1.5 h. Subsequent stirring at 0° C. for 1 h. The mixture was poured onto icewater (2000 ml) neutralised with NaHCO3 whereafter the mixture was stirred overnight. The aqueous phase was decanted and the organic phase evaporated followed by extraction with ethanol (boiling). The ethanolic phase was evaporated and the crystalline residue recrystallized from ethanol yielding 70 g of (1), m.p. 227° C.

Provenance & Evidence