Originator
Ipropran,Roche,W. Germany,1981
Manufacturing Process
2-Isopropyl-4 (or 5-nitroimidazole) (31 g = 0.2 mol), dioxane (70 g) and
dimethylsulfate (28 g = 0.22 mol) were heated on a steam bath under reflux
for 45 minutes. The solvent was removed in vacuo on a steam bath, the
residue dissolved in 20 ml of water and the product precipitated by the
gradual addition of 80 g of 25% sodium hydroxide solution at 0°C. A small
additional amount was obtained by extraction of the mother liquor with
methylene chloride. The product melted at 60°C.
The product was purified as follows. 60 g of product was dissolved in 3N
aqueous hydrochloric acid, the solution was treated with charcoal and filtered.
The filtrate was neutralized by the gradual addition of aqueous concentrated
ammonia at 0°C to 5°C under stirring whereupon the product precipitated in
white plates as the neutralization proceeded. The precipitate was filtered by
suction, washed on the filter with 50 ml of ice cold water and dried at room
temperature, MP 60°C.
The hydrochloride salt was formed by reacting the product, dissolved in
isopropanol, with 25% ethanolic hydrochloric acid, whereupon the salt
precipitated and was isolated. It has a melting point of 177°C to 182°C (dec).
Similarly, the bisulfate salt was formed using 96% sulfuric acid. It has a MP of
151.5°C to 152.5°C.
