1H-Pyrrolo(2,3-b)pyridine → 1H-Pyrrolo[2,3-b]pyridine-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

Phosphorus oxychloride (36.5 mL) was added dropwise to cooled solution of DMF (40 mL) while maintaining the temperature below 10° C. The resulting solution was further cooled to 5° C. and a solution of 7-azaindole in DMF (40 mL) was added slowly over 30–40 min, maintaining the temperature below 25° C. The mixture was heated at 95° C. for 48 h then cooled to 35° C. and added cautiously with stirring over an hour to a cooled solution of saturated aqueous sodium bicarbonate solution (800 mL). The mixture was extracted with ethyl acetate (4×500 mL) and the combined extracts washed with water (500 mL) and brine (500 mL), then dried (MgSO4), filtered and concentrated in vacuo to afford a dark brown semi-solid. This crude product was purified using column chromatography eluting with a 50:50 mixture of ethyl acetate:hexane, gradually increasing to 90:10 mixture. 1H-NMR (400 MHz/D6-DMSO): δ=7.25 (m, 1H), 8.38 (m, 2H), 8.42 (s, 1H), 9.92 (s, 1H), 12.62 (br.s, 1H). MS (ES+): 147 [MH+].

Provenance & Evidence