3-formyl-N-methyl-1H-indole-2-carboxamide → N-methyl-3-vinyl-1H-indole-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (2.5M in hexanes) (48.6 mL, 121.7 mmol) was added dropwise to an ice-cooled solution of methyl triphenylphosphoniumbromide (43.5 g, 121.7 mmol) in THF (500 mL). The mixture was stirred at 0° C. for 1 h then at rt for 2 h. 3-Formyl-N-methyl-1H-indole-2-carboxamide (1.96 g, 9.7 mmol) in THF (100 mL) was added and the mixture stirred at rt for 2 h. The solvent was evaporated and the residue dissolved in ethyl acetate and washed twice with water. The organic phase was dried over magnesium bromide and evaporated in vacuo. The crude mixture was chromatographed over silica gel eluting with 40% ethyl acetate in hexanes to afford the title compound (730 mg (38%). 1H NMR (300 MHz, DMSO-d6) δ 11.48 (s, 1H), 8.04 (s, 1H), 7.92 (d, J=8.0 Hz, 1H), 7.42 (d, J=7.9 Hz, 1H), 7.33 (d, J=18 Hz, 1H), 7.22 (t, J=7.6 Hz, 1H), 7.09 (t, J=7.2 Hz, 1H), 5.77 (d, J=18.4 Hz, 1H), 5.27 (d, J=11.6 Hz, 1H), 2.81 (s, 3H).

Provenance & Evidence