Isothiocyanatotrimethylsilane → 5-(1H-Indol-3-ylmethyl)-2-thioxo-4-imidazolidinone

Participants

Reaction Steps

To a solution of L-tryptophan methyl ester hydrochloride (0.257 mg, 0.001 mol.) in dichloromethane (10 mL) was added DMAP (5.0 mg), diisopropylethylamine (10 eq.) and then trimethylsilylisothiocyanate (1.3 gm, 0.01 mol.). The reaction mixture was stirred at room temperature for 24 hr, and then concentrated. The residue obtained was dissolved in AcOH (10 mL) and refluxed for 6 h. The reaction mixture was concentrated and dried under vacuum. The solid obtained was suspended in EtOAc, filtered, washed with EtOAc, and dried under vacuum to give 893-18 (230 mg, 94%): mp 206-210° C., 1H NMR (500 MHz, DMSO-d6): 3.00—yield 34%, 1H NMR (500 MHz, CDCl3): 3.24-3.33 (m, 2H), 4.23-4.26 (m, 1H), 7.01 (dd, J=8.0 and 7.0 Hz, 1H), 7.09 (dd, J=8.0 and 7.0 Hz, 1H), 7.23 (d, J=2.0 Hz, 1H), 7.37 (d, J=8.0 Hz, 1H), 7.50 (d, J=8.0 Hz, 1H), 8.50 (s, 2H), 11.08 (s, 1H).

Provenance & Evidence