Dimethyl Sulfate → Ipronidazole

Participants

Reaction Conditions

Reaction Steps

155 parts of 2-isopropyl-5-nitroimidazole, 350 parts of formic acid and 126 parts of dimethyl sulfate are heated under reflux for 2 hours. The formic acid is distilled off in vacuo and the residue which remains is dissolved in 500 parts of water. A pH of 1.8 is set up with dilute aqueous ammonia solution and the solution is cooled for 2 hours at +5° C. The unreacted 2-isopropyl-5-nitroimidazole (15 parts) is suction filtered and the filtrate is adjusted to pH 10 by adding aqueous ammonia solution. After cooling for 2 hours at 5° C. the mixture is suction filtered and the end product is dried. 110 parts of 1-methyl-2-isopropyl-5-nitroimidazole having a melting point of 56° C. is obtained and this is equivalent to a yield of 72% of theory based on reacted 2-isopropyl-5-nitroimidazole.

Provenance & Evidence