The invention relates to a compound of general formula (I) or a salt thereof, for use as a pharmaceutical composition for treating infectious diseases, especially for treating diseases caused by Helicobacter. R1 is an H atom, an X atom or a CX m H 3-m radical wherein each X can be the same or different and is a halogen selected from F, C1, Br or I, and m is a value between 1 and 3；R 2 is an NO 2 group, a COOR', group or an SO 3 R' group； R' is a Hydrogen (H) atom or a C 1 - C 6 alkyl group； and n is a value between 1 and 5.
