Dimethylformamide → Methyl 3-formyl-1H-indole-5-carboxylate

Participants

Reaction Steps

Place anhydrous DMF (25 mL) in a flask under an atmosphere of nitrogen, cool to 10° C. and treat dropwise with POCl3 (8.22 g, 54 mmol) while keeping the temperature below 15° C. Add a solution of 5-methoxycarbonyl-1H-indole in 30 mL DMF portionwise keeping the temperature below 20° C. Remove the cooling bath and stir the mixture at ambient temperature for 1 hour then pour onto ice. Addition of 50 mL 5N NaOH precipitated a solid which is filtered and rinsed with water and EtOAc to give the title compound: 1H NMR (DMSO-d6) 9.95 (s, 1H), 8.76 (s, 1H), 8.4 (s, 1H), 7.9–7.8 (m, 1H), 7.5–7.7 (d, 1H), 3.85 (s, 3H), 1.7 (s, 1H); ISMS 204 (M+1).

Provenance & Evidence