Hydrochloric Acid → Hydroxyipronidazole

Participants

Reaction Steps

A total of 45 ml of a 2.25-N solution of sodium tert.amylate in toluene and 11.2 ml of triethylphosphite were added to a solution, cooled to -15°, of 8.5 g of 1-methyl-2-isopropyl-5-nitroimidazole in 85 ml of dimethylformamide. A strong oxygen stream was conducted through this mixture for 6 hours at a temperature of -10° to -15° while stirring vigorously. The mixture was then neutralized by the addition of 45 ml of 2-N hydrochloric acid and concentrated on a rotary evaporator at 50°/12 Torr. The residue was taken up in 250 ml of water and the aqueous solution extracted 3 times with 250 ml portions of dichloromethane. The combined dichloromethane extracts were washed with a small amount of water and concentrated to dryness. The residue was then taken up in ethyl acetate and chromatographed on 600 g of silica gel with ethyl acetate. After evaporation of the solvent on a rotary evaporator and crystallization from isopropyl ether, there were obtained 2.2 g of 2-(2-hydroxy-2-propyl)-1-methyl-5-nitroimidazole, melting point 106°-108°. The yield was 23.8%.

Provenance & Evidence