Hydrochloric Acid → Hydroxyipronidazole

Participants

Reaction Steps

A total of 21.5 g of potassium were dissolved in 450 ml of tert.-butanol with vigorous stirring and the solution heated to reflux. 300 ml of hexametapol were added to the cooled solution. The mixture was then cooled to -25°, a solution of 42.5 g of 1-methyl-2-isopropyl-5-nitroimidazole in 60 ml of triethylphosphite and 150 ml of hexametapol was added and dry oxygen was conducted through the mixture for 5 hours at -20° to -25° with vigorous stirring. The mixture was poured into a mixture of 1.5 liter of ice-water and 45 ml of 36% hydrochloric acid and extracted six times with 400 ml portions of ether. The combined ether extracts were washed twice with 250 ml portions of water and evaporated. The crude 2-(2-hydroxy-2-propyl)-1-methyl-5-nitroimidazole (40.5 g; 87%) was purified by crystallization from 300 ml of water. There were obtained 30.2 g of pure 2-(2-hydroxy-2-propyl)-1-methyl-5-nitroimidazole, melting point 106°-108° and a second crop of 4.2 g, melting point 102°-105° (total yield 74%).

Provenance & Evidence