1-Alkyl-2-hydroxymethyl-5-nitro-imidazoles prepn. - by reacting 1-alkyl-5-nitroimidazoles with formaldehyde and secondary amines

1-Alkyl-2-hydroxymethyl-5-nitroimidazoles of formula (where R1 is methyl, ethyl or 2-hydroxyethyl), e.g. 1-methyl-2-hydroxymethyl-5-nitroimidazole, are prepd. by reacting a 1-alkyl-5-nitroimidazole of formula (II) with either (a) formaldehyde, paraformaldehyde, a functional formaldehyde deriv. or a formaldehyde-forming agent in the presence of a secondary amine of formula (III) (where R2 and R3 are 1-6C alkyl, cyclopentyl, cyclohexyl, benzyl or phenyl, or are linked so as to form a pyrrolidine, piperidine, morpholine, piperazine, imidazolidine or imidazole ring) at elevated temp., or (b) an N-hydroxymethylamine of formula (IV) at elevated temp. (I) are inters. for pharmaceuticals. The new process avoids the disadvantages of the process known from DT 1470102 (working under pressure in an autoclave; use of the expensive and hazardous solvent dimethyl sulphoxide). (I) are obtd. in very good yields.