1,154,290. Imidazole derivatives. MERCK & CO. Inc. 4 July, 1966 [7 July, 1965; 18 May, 1966], No. 35038/68. Divided out of 1,153,347. Heading C2C. Novel imidazole derivatives of the general formula wherein R<SP>1</SP> 1 is a hydroxyalkyl, carboxyalkyl or alkyl radical or an alkyl radical having an oxo, halo, alkenyl, alkanoyloxy, aralkanoyloxy, alkoxy, aralkoxy, alkoxycarbonyl, aralkoxycarbonyl, alkylcarbamoyl, aralkylcarbamoyl, arylcarbamoyl, carbamoyl, cyano, alkylthio, aralkylthio, alkylsulphinyl, aralkylsulphinyl, arylsulphinyl, alkylsulphonyl, aralkylsulphonyl or arylsulphonyl substituent; Q is arylmethylene or arylethylidene, or an alkylene, alkenylene or alkylidene radical containing not more than five carbon atoms, W is nitro, cyano, phenyl or hydrogen, and P is hydrogen or nitro; provided that one and only one of W and P is nitro and that when Q is methylene, R<SP>1</SP> 1 is not methyl; the alkyl, alkanoyl and alkoxy radicals referred to above having from 1 to 5 carbon atoms; are prepared, for example, by the following methods: (a) treatment of a 2-alkyl-substituted imidazole with paraformaldehyde in dimethylsulphoxide; (b) reaction of a 2-formyl-imidazole with an alkyl magnesium iodide in ether; (c) reduction of a 2-alkanoylimidazole with sodium borohydride; (d) reduction of an imidazol-2-yl-alkenal with sodium borohydride; and (e) treatment of an imidazol-2- yl-alkenol with potassium azodicarboxylate. Pharmaceutical compositions, useful against parasitic diseases, amoebiasis, trypanosomiasis and chronic respiratory diseases in fowl and having antibacterial activity, comprise as active ingredient an imidazole derivative of the above general formula and an inert diluent, carrier or coating. 1 - Methyl - 2 - formyl - 5 - nitroimidazole is prepared by oxidation of 1-methyl-2-hydroxymethyl - 5 - nitroimidazole with lead tetracetate. 1 - Methyl - 2 - acetyl - 5 - nitro - imidazole is prepared by reaction of 1-methyl-2-formyl- 5-nitroimidazole with diazomethane in the presence of boron trifluoride etherate. 1- Methyl - 2 - benzoyl - 5 - nitroimidazole is prepared by nitration of 2-benzylimidazole with nitric acid in acetic anhydride, treatment of the resulting 2-benzyl-4:(5)-nitroimidazole with dimethyl sulphate and oxidation of the produced 1 - methyl - 2 - benzyl - 5 - nitroimidazole with sodium dichromate dihydrate in sulphuric acid. 3 - (1 - Methyl - 5 - nitroimidazole - 2 - yl) - prop- 2 - en - 1 - al is prepared by reaction of 1- methyl-2-formyl-5-nitro-imidazole with formylmethyltriphenylphosphorane. 1- Methyl - 2 - hydroxymethyl - 5 - nitroimidazole is prepared by treatment of 1-methyl-5-nitroimidazole with paraformaldehyde in dimethylsulphoxide.