Dimethylformamide → 3-Formyl-2-methylindole

Participants

Reaction Steps

To a dried 300 mL two-neck round bottom flask under argon at 0° C., N,N-dimethylformamide (3 mL) was added, followed by POCl3 (1.05 mL, 11.3 mmol). After stirring for ten minutes, 2-methylindole (1.23 g, 9.37 mmol) dissolved in DMF (6 mL) was added dropwise via an addition funnel under argon. After two hours, 1 N NaOH (70 mL) was added slowly, upon which a white precipitate formed. The solid was filtered and dried under vacuum, yielding 1.32 g (89%) of white solid. 1H NMR (600 MHz, d6-DMSO): δ 11.998 (s, 1H, N—H), 10.050 (s, 1H, CHO), 8.044-8.032 (d, J=7.2, 1H, indole-4H), 7.388-7.375 (d, J=7.8, 1H, indole-7H), 7.183-7.135 (m, 2H, indole-5,6H), 2.679 (s, 3H, methyl). 13C NMR (150 MHz, d6-DMSO): δ 184.3, 148.6, 135.4, 125.6, 122.7, 121.9, 120.0, 113.7, 111.4, 11.5. Melting Point: 195-200° C. TLC (ethyl acetate:hexanes 4:1) Rf=0.39. Elemental analysis calculated for C10H9NO: C, 75.45; H, 5.70; N, 8.80. found: C, 75.23; H, 5.70; N, 8.93.

Provenance & Evidence