The present invention relates to new antimicrobial compounds, their synthesis and their use for treatment of mammalian infections. The present invention aims at the generation of new compounds with activity against mycobacteria as potential new tuberculosis drugs to overcome problems concerning resistance and drug intolerance. This aim has been solved by providing compounds of the formula 1 wherein R1 and R2 are, independently of each other, NO2, NR7R8, NHOR9, COOR9, CN, CONR10R11, CHO, F, Cl, Br, SO2NR12R13, lower alkoxy, OCF3, mono-, di or trifluoromethyl R3 and R4 are, independently of each other, H, a saturated or unsaturated, linear or branched aliphatic radical having 1 -3 chain members, F, Cl, Br, lower alkoxy R5 is H, a saturated or unsaturated, halogenated or unhalogenated, linear or branched aliphatic radical having 1-7 chain members R6 is a radical: wherein X is saturated or unsaturated, halogenated or unhalogenated, linear or branched aliphatic radical having 1-5 chain members, or R5 and R6 together represent bivalent radicals wherein n is 1-4: R7- R13 are, independently of each other H or a saturated or unsaturated, halogenated or unhalogenated, linear or branched aliphatic radical having 1 -5 chain members, phenyl, benzyl or R7 and R8 together, R
