Sulfuric Acid → Ethyl 5-(phenylmethoxy)-1H-indole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of sulfuric acid (80.0 mL, 1.50 mol) dissolved in Ethanol (450 mL) at 0° C. was added (4-(benzyloxy)phenyl)hydrazine hydrochloride (90.0 g, 359 mmol) to form a suspension. To the suspension was added ethyl 2-oxopropanoate (43.9 mL, 395 mmol) in EtOH (90 mL) and mechanically stirred for 2 h using a mechanical stirrer. The mixture was heated to 45° C. and maintained for 16 h. The mixture was cooled to room temperature and cold EtOH (200 mL) was added. The mixture was filtered through a course frit. The collected solid was washed sequentially with cold EtOH, hexanes, and water. The solid was dried in a vacuum oven (45° C., 2 Ton) to give ethyl 5-(benzyloxy)-1H-indole-2-carboxylate (73.1 g, 247 mmol, 69% yield). Exact mass calculated for C18H17NO3: 295.1, found: LCMS m/z=296.2, [M+H+]; 1H NMR (400 MHz, CDCl3) δ ppm 1.41 (t, J=7.1 Hz, 3 H), 4.40 (q, J=7.1 Hz, 2 H), 5.10 (s, 2 H), 7.08 (dd, J1=8.9, J2=2.4 Hz, 1 H), 7.14 (d, J=1.6 Hz, 1 H), 7.20 (d, J=2.3 Hz, 1 H), 7.32 (m, 2 H), 7.39 (m, 2 H), 7.47 (m, 2 H), 8.75 (bs, 1 H).

Provenance & Evidence