The antibacterial compound of formula I wherein X1, X3; X4 and X6, each independently of the others, represents a nitrogen atom or CR2, with the proviso that at least one of X1, X3; X4 and X6 represents a nitrogen atom; X2 represents C—H, C—(C1-C6alkyl), C—(C1-C6alkoxy), C-halogen, C—COOH; X5 represents C—H or C—(C1-C6alkyl), C-halogen; A1, A2, A3, R1 and R4 represent various substituents, G represents aryl or heteroaryl, which is unsubstituted or substituted which compounds show good activity against pathogenic bacteria.