Acetyl chloride → HCID 13160404, compound

Participants

Reaction Steps

Acetyl chloride (0.76 ml) was added to a suspension of anhydrous aluminium (III) chloride (1.42 g) in 1,2-dichloroethane (20 ml) at 0° C. The reaction was stirred for 5 minutes then a solution of ethyl indole-2-carboxylate (1 g) in 1,2-dichloroethane (20 ml) was added dropwise over 10 minutes. The reaction was heated at reflux for 1 hour, cooled and poured into ice/water. The solution was partitioned between ethyl acetate and saturated aqueous sodium-hydrogen carbonate solution. Combined organic extracts were dried (MgSO4) and concentrated in vacuo and the residue purified by column chromatography using isohexane-10% ethyl acetate as eluent to give firstly ethyl 7-acetylindole-2-carboxylate as a white solid (0.1 8 g, 15%); NMR δ(CD3SOCD3) 1.35 (t, 3H), 2.7 (s, 3H), 4.4 (q, 2H), 7.3 (m, 2H), 8.05 (m, 2H), 10.7 (bs, 1H); M/z (+) 232 (MH+), followed by ethyl 3-acetylindole-2-carboxylate as a white solid (0.2 g, 16%); NMR δ(CD3SOCD3) 1.35 (t, 3H), 2.6 (s, 3H), 4.4 (q, 2H), 7.2 (t, 1H), 7.3 (t, 1H), 7.5 (d, 1H), 7.9 (d, 1H), 12.4 (bs, 1H); M/z (+) 232 (MH+), followed by ethyl 5-acetylindole-2-carboxylate as a white solid (0.5 g, 42%); NMR δ(CD3SOCD3) 1.35 (t, 3H) 12.6 (s, 3H), 4.35 (q, 2H), 7.3 (s, 1H), 7.5 (d, 1H), 8.4 (s, 1H), 12.2 (bs, 1H); M/z (+) 232 (MH+).

Provenance & Evidence