Hydrochloric Acid → 3-Ethyl-5-(1H-indol-3-ylmethyl)-imidazolidine-2,4-dione

Participants

Reaction Steps

To a solution of L-tryptophan methyl ester hydrochloride (0.510 mg, 0.002 mol.) in dichloromethane (10 mL) was added triethyl amine (0.350 mL, 0.0025 mol.) followed by ethylisocyanate (0.198 mL, 0.0025 mol.). The reaction mixture was stirred at room temperature for 24 hr, and then concentrated. The residue obtained was diluted with dioxane (10 mL) and then conc. HCl (5 mL) was added. The mixture was heated at reflux for 3-4 hr. The reaction mixture was extracted in ethyl acetate, washed with water, dried and concentrated. The residue was purified by column chromatography on silica gel using 60% ethyl acetate-hexane to give 893-04 (480 mg, 93%): mp 167-170° C. (lit. 163-164° C.), 1H NMR (400 MHz, CDCl3): 0.99 (t, J=6.8 Hz, 3H), 2.95-3.01 (dd, J=8.4 and 14.8 Hz, 1H), 3.34-3.46 (m, 3H), 4.19-4.22 (dd, J=3.6 and 8.8 Hz, 1H), 5.70 (s, 1H), 6.98 (d, J=2.0 Hz, 1H), 7.06-7.10 (dd, J=8.0 and 6.8 Hz, 1H), 7.16 (dd, J=7.2 and 6.8 Hz, 1H), 7.30 (d, J=8.4 Hz, 1H), 7.55 (d, J=8.8 Hz, 1H), 8.18 (s, 1H).

Provenance & Evidence