Nitric Acid → Ethyl 1-methyl-4-nitroimidazole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

Compound (17) was carefully dissolved in 1000 ml of concentrated sulfuric acid cooled to 0° C. 90% nitric acid (1 liter) was slowly added maintaining a temperature of 0° C. The reaction was then refluxed with an efficient condenser (−20° C.) in a well ventilated hood for 50 minutes. The reaction was cooled with an ice bath, and quenched by pouring onto 10 liters of ice. The resulting blue solution was then extracted with 20 liters of dichloromethane and the combined extracts were dried and concentrated in vacuo to yield a tan solid which was recrystallized from 22 liters of 21:1 carbon tetrachloride/ethanol. The resulting white crystals were collected by vacuum filtration to provide pure (10). (103 g, 22% yield). TLC (7:2 benzene/ethyl acetate) Rf 0.5, 1H NMR (DMSO-d6) δ8.61 (s, 1 H), 4.33 (1, 2 H, J=6.4 Hz), 3.97 (s, 3 H), 1.29 (t, 3 H, J=6.0 Hz): 13C NMR (DMSO-d6) δ158.2, 145.4, 135.3, 127.4, 62.2, 37.3, 14.5; IR(KBr) 3139, 1719, 1541, 1508, 1498, 1381, 1310, 1260, 1147, 1122, 995, 860, 827, 656; FABMS m/e 200.066 (M+H 200.067 calc. for C7H10N3O4).

Provenance & Evidence