Indole → N-methoxy-N-methyl-3-(indol-5-yl)acrylamide

Participants

Reaction Steps

A mixture of sodium hydride (0.44 g of a 60% suspension in mineral oil, 11 mmol) and diethyl-(N-methoxy-N-methyl-carbamoylmethyl)-phosphonate (3.0 g, 3 equiv.) in anhydrous THF was stirred at room temperature for 30 minutes. A solution of indole-5-carboxaldehyde (0.61 g, 4.18 mmol) was added dropwise to the mixture. The reaction was complete after 2 h after the addition of the starting indole. The mixture was quenched with water (50 ml), then diluted with ether. The organic layer was separated, dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo to give N-methoxy-N-methyl-3-(indol-5-yl)acrylamide as a yellow oil which solidified on standing to an off-white solid (1.53 g, quantitative yield. 1H NMR (CDCl3): δ 8.55 (br, 1H), 7.87 (d, J=18.6 Hz, 1H), 7.85 (s, 1H), 7.38 (d, J=8.5 Hz, 1H), 7.25 (d, J=8.5 Hz, 1H), 7.23 (m, 1H), 7.0 (d, J=18.6 Hz, 1H), 6.58 (m, 1H), 3.78 (s, 3H), and 3.32 (s, 3H). FIMS: 229.1 (M−H)−, reverse-phase HPLC purity: 88%.

Provenance & Evidence