Triethylamine → 5H-Imidazo[2,1-a]isoindole-2-carbaldehyde

Participants

Reaction Steps

The solution of 2-bromo-3-isopropoxy-propenal (4.97 g) in dry acetonitrile (3 mL) was added to the mixture of 3-amino-1H-isoindole (3.4 g) in dry acetonitrile (100 mL). The reaction mixture was stirred for 3.25 h at room temperature. Then triethylamine (3.6 mL) was added to the mixture and heated to reflux for 2 h. The mixture was cooled to room temperature, diluted with ethyl acetate, and washed with 20% potassium hydrogen carbonate. After filtration through a pad of Celite, the organic layer was dried (MgSO4) and concentrated under reduced pressure. The residue was applied to silica gel column chromatography, then eluted with ethyl acetate—hexane (3/1˜4/1). The crude compound was crystallized from ethyl acetate and n-hexane to give the title compound (1.04 g, 22%). 1H NMR (400 MHz, CDCl3) δ 5.01 (s, 2H), 7.28–7.52 (m, 3H), 7.90 (s, 1H), 7.91–7.93 (m, 1H), 9.92 (s, 1H).

Provenance & Evidence