Dimethylformamide → 2-Phenylindole-3-carboxaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of DMF (11.0 mL, 142 mmol) and phosphorous oxychloride (3.63 mL, 39 mmol) is stirred at 0° C. for 1 h, a 0.2 mL portion is pipetted into a solution of 2-phenylindole (96 mg, 0.5 mmol) in DMF at 5° C. This reaction mixture is stirred at 5°-10° C. for 1 h, quenched with water, stored at −200 for 16 h and filtered. The filtercake is washed with water and dried in vacuo to afford the 2-phenylindole-3-carboxaldehyde intermediate. A suspension of the thus-obtained 2-phenylindole-3-carboxaldehyde (44.2 mg, 0.2 mmol) in isopropanol and concentrated HCl (50 μL) is treated with aminoguanidine bicarbonate (27 mg, 0.2 mmol), heated at 80° C. for 2 h, cooled to room temperature and concentrated in vacuo. The resultant residue is purified by HPLC to afford the title product, 28 mg (20% yield), identified by mass spectral and HPLC analyses (M+H) 277; retention time 3.76 min.

Provenance & Evidence