1-Methylimidazole → ethyl 1-methyl-1H-imidazole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

N-methylimidazole (16) (320 g, 3.9 mol) was combined with 2 liters of acetonitrile and 1 liter of triethylamine in a flask equipped with a mechanical stirrer and the solution was cooled to −20° C. Ethylcloroformate (1000 g, 9.2 mol) was added with stirring, keeping the temperature between −20° C. and −25° C. The reaction was allowed to slowly warm to room temperature and stir for 36 hours. Precipitated triethylamine hydrochloride was removed by filtration and the solution was concentrated in vacuo at 65° C. The resulting oil was purified by distillation under reduced pressure (2 torr, 102° C.) to provide (17) as a white solid (360 g, 82% yield). TLC (7:2 benzene/ethyl acetate) Rf 0.2; 1H NMR (DMSO-d6) δ7.44 (d, 1 H, J=2.8 Hz), 7.04 (d. 1 H, J=2.8 Hz), 4.26 (q, 2 H, J=3.5Hz) 3.91 (s, 3 H), 1.26 (t, 3 H, J=3.5 Hz); 13C NMR (DMSO-d6) δ159.3, 129.1, 127.7, 61.0, 36.0, 14.5; IR(KBr) 3403, 3111, 2983, 1713, 1480, 1422, 1262, 1134, 1052, 922, 782, 666; FABMS m/e 155.083 (M+H 155.083 calc. for C7H11N2O2).

Provenance & Evidence