Imidazoles and pharmaceutical composition

#The invention relates to new imidazoles of the formula ##STR2## wherein one of the radicals R.sub.1 and R.sub.2 denotes hydrogen or lower alkyl and the other denotes the nitro group, R.sub.3 is lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, lower alkyl-sulphonyl-lower alkyl or amino-lower alkyl, R.sub.4 is oxo or thioxo, R.sub.5 -- if R.sub.1 is the nitro group -- is hydrogen, lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, amino-lower alkyl, acyl, aryl or a heterocyclic radical or R.sub.5 -- if R.sub.2 is the nitro group -- is aryl or a heterocyclic radical, with the exception of an optionally substituted 2-imidazolyl group, and alk is lower alkylene, as well as processes for their manufacture.

#In the preceding and following text, lower radicals are above all radicals which contain up to 7 C atoms, especially up to 4 C atoms.

#Examples of lower alkyl radicals are methyl, ethyl, n-propyl or isopropyl or straight-chain or branched butyl, pentyl, hexyl or heptyl, which can be bonded in any desired position.

#The invention is described in more detail in the examples which follow.

#A solution of 8.5 g of 1-[thiazolyl-(2)]-2-oxotetrahydroimidazole in 200 ml of dimethylformamide is added dropwise over the course of 1 hour to a suspension of 2.4 g of 50% strength sodium hydride in 50 ml of dimethylformamide at 20.degree. C to 30.degree. C, whilst stirring. Thereafter, the mixture is stirred for a further hour at 20.degree. C to 30.degree. C. 10.3 g of 1-methyl-2-methylsulphonyl-5-nitro-imidazole, dissolved in 75 ml of dimethylformamide, are then added and the whole is stirred for a further hour at 90.degree. C to 100.degree. C. Thereafter the reaction mixture is evaporated and the evaporation residue is washed with petroleum ether, triturated with approx. 50 ml of water, filtered off and first washed thoroughly with water and then with methanol. The crude product is recrystallised from 100 ml of 2-ethoxyethanol. The 1-[thiazolyl-(2)]-2-oxo-3-[ 1-methyl-5-nitro-imidazolyl-(2)]-tetrahydroimidazole thus obtained, of the formula ##STR8## melts at 226.degree. C.

#10 g of 1,3-di-[1-methyl-5-nitro-imidazolyl-(2)]-2-oxo-tetrahydroimidazole (melting point 211.degree. C-212.degree. C), 25 g of potassium iodide and 125 ml of dimethylformamide are heated for 20 hours under reflux. The reaction mixture is then evaporated to dryness and the evaporation residue is triturated with water and filtered off. The crude product is first recrystallised from 35 ml of dimethylformamide and then again recrystallised from 50 ml of dimethylformamide. 1,3-Di-[1-methyl-4-nitro-imidazolyl-(2)]-2-oxo-tetrahydroimidazole thus obtained, of the formula ##STR9## melts at 263.degree. C-265.degree. C.