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

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).

1. temperatureheated
2. temperatureto reflux for 2 h
3. temperatureThe mixture was cooled to room temperature
4. washwashed with 20% potassium hydrogen carbonate
5. filtrationAfter filtration through a pad of Celite
6. dry with materialthe organic layer was dried (MgSO4)
7. concentrationconcentrated under reduced pressure
8. washeluted with ethyl acetate—hexane (3/1˜4/1)
9. customThe crude compound was crystallized from ethyl acetate and n-hexane

ORD record

ord-03c9924f151046bdbd5d92542297e64f

Source dataset

uspto-grants-2006_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07018997B2