1-Nitropropane → 5-Bromo-3-cyanoindole

Participants

Reaction Steps

Commercially available 5-bromoindole-3-carboxaldehyde (11.3 g, 50.4 mmol), ammonium hydrogen phosphate (47.0 g, 353 mmol), 1-nitropropane (4.49 g, 50.4 mmol), and glacial acetic acid (100 ml) were heated at a gentle reflux for 18 h. The resulting mixture was concentrated in vacuo and the residue mixed with 5 N sodium hydroxide (500 ml) and ice chips. The precipitate was collected by filtration and rinsed several times with water. The filtrate was concentrated in vacuo to afford 5-bromo-3-cyanoindole (7.23 g, 65%) as a dark solid. 1H-NMR (400 MHz, CDCl3) δ10.0 (1H, s), 8.68 (1H, br s), 8.51 (1H, s), 7.85 (1H, s), 7.43 (1H, dd, J=8.6, 1.9 Hz), 7.32 (1H, d, J=8.6 Hz).

Provenance & Evidence