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

Temperature

-20 °C

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).

1. customequipped with a mechanical stirrer
2. customthe temperature between −20° C. and −25° C
3. temperatureto slowly warm to room temperature
4. stirringstir for 36 hours
5. customPrecipitated triethylamine hydrochloride was removed by filtration
6. concentrationthe solution was concentrated in vacuo at 65° C
7. distillationThe resulting oil was purified by distillation under reduced pressure (2 torr, 102° C.)

ORD record

ord-d94d6e4ebf754cfa94bae182c3237780

Source dataset

uspto-grants-2003_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06545162B1