GB837838A - New imidazole derivatives and processes for their preparation - Google Patents

Abstract

The invention comprises compounds of the general formula <FORM:0837838/IV (b)/1> p and their acid addition salts (wherein R1 is methyl or ethyl and R2 is an alkyl group with not more than six carbon atoms, such that the total number of carbon atoms in R1 and R2 is at least 3), and the preparation thereof by (1) alkylating a nitroimidazole of the general formula <FORM:0837838/IV (b)/2> or (2) nitrating an imidazole of the general formula <FORM:0837838/IV (b)/3> and separating from the reaction product the desired nitroimidazole. 2-Ethyl-4(5)-nitroimidazole is made by nitrating the acid sulphate of 2-ethylimidazole.ALSO:Pharmaceutical compositions comprise one or more compounds of the general formula <FORM:0837838/VI/1> or an acid addition salt thereof (wherein R1 is methyl or ethyl and R2 is an alkyl group with not more than six carbon atoms, such that the total number of carbon atoms in R1 and R2 is at least 3) and a significant amount of a pharmaceutical carrier which may be a solid or liquid. They may be administered orally (e.g. as emulsions, elixirs, powders, solutions, suspensions, syrups or tablets), parenterally (e.g. as sterile solutions or suspensions in water or other liquids, with or without the addition of soluble or insoluble diluents and/or solid or liquid excipients) or topically (e.g. by incorporation in a suitable vehicle such as a cream, lotion, ointment, ovule, pessary or suspension). Unit dose forms may be compressed powders (or tablets) or powders enclosed in suitable capsules of absorbable material such as gelatin. The compressed powders (or tablets) can take the form of the active materials admixed with suitable excipients and/or diluents such as dextrin, lactose, magnesium stearate, starch or stearic acid. Generally, the compositions should contain at least 0.025% by weight of active substance in the case of injectable solutions and at least 0.1% by weight of such substance in the case of oral preparations. The active material may, as such or in the form of a diluted composition, be put up in powder packets and employed as such. The compositions are particularly of value in the treatment of infections due to pathogenic protozoa such as certain species of amaeba or of trichomonas.