of the compound of formula ii from 1 to 5 mols preferably 1 to 2 mols of each of the reaction components of formulae iii iv or v and in addition from 1 to 10 mols and preferably from 1 to 2 mols of an acid binder in cases where an acid is liberated it is possible to derivate considerably from the aforementioned molar ratios without adversely affecting the result of the reaction to any real extent to carry out the process according to the invention the compound of formula ii is dissolved or suspended in a diluent and the second reaction component of formulae iii iv or v and optionally the acid binder is added in portions to the resulting solution or suspension the reaction components can be combined in any order in most cases the end products of formula i are precipitated after a short time in crystalline form optionally following concentration of the diluent by evaporation they can be isolated and purified by conventional methods for example by recrystallization the following are specifically mentioned as examples of the new active substances the active substances of formula i show pronounced anti microbial activity their activity covers for example gram positive and gram negative bacteria the following families geni and species of bacteria being mentioned by way of example enterobacteriaceae for example eschericha especially escherichia coli klebsiella especially klebsiella pneumoniae enterobacter proteus especially proteus vulgaris proteus mirabilis proteus morganii proteus rettgeri and.