Novel compound with antibacterial activity

A compound represented by the following general formula (I):

• wherein, in the formula, R1 represents a C1-C6 alkyl group which may have a substituent, a C1-C6 alkenyl group which may have a substituent, or an aryl group which may have a substituent, provided that R1 may bind with R6 to form a partially unsaturated or saturated heterocyclic ring containing one or two or more ring-constituting heteroatoms (the ring may have a substituent);
• R2 represents hydrogen atom, carboxyl group, or amino group;
• R3 represents hydroxy group, or a C1-C6 alkyl group which may have a substituent;
• R4 represents hydrogen atom, a halogen atom, a C1-C6 alkyl group which may have a substituent, or a C1-C6 alkoxy group which may have a substituent, provided that R4 may bind with R5 to form a partially unsaturated or saturated heterocyclic ring containing one or two or more ring-constituting heteroatoms (the ring may have a substituent);
• R5 represents a C1-C6 alkyl group which may have a substituent, a C1-C6 alkoxy group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a partially saturated or saturated heterocyclic group which may have a substituent, provided that R5 may bind with R6 to form a partially unsaturated or saturated heterocyclic ring containing one or two or more ring-constituting heteroatoms (the ring may have a substituent);
• and R6 represents hydrogen atom, a C1-C6 alkyl group which may have a substituent, a C1-C6 alkoxy group which may have a substituent, or a halogen atom, or a salt thereof.