Benzimidazole derivatives

Benzimidazole derivatives which are represented by a general formula [I-1]

• in which
• X stands for a hydrogen or halogen,
• B stands for a halogen, cyano or optionally fluorine-substituted lower alkyl,
• D stands for a group selected from a group consisting of the following formulae [D-1],
• wherein
• m1 is 0 or an integer of 1 or 2
• R1 stands for hydrogen or a lower alkyl which may optionally be substituted with at least one substituent selected from a group consisting of halogen, hydroxyl, lower alkyloxy and lower cycloalkyl;
• R2 may be same or different where m1 is 2, and stand for lower alkyl which may optionally be substituted with a substituent selected from a group consisting of halogen, hydroxyl, optionally fluorine-substituted lower alkyloxy, lower alkylcarbonyl, carboxyl, lower alkyloxycarbonyl, carbamoyl, mono-lower alkylcarbamoyl and di-lower alkylcarbamoyl,
• stands for a piperazine ring;
• R3 stands for hydrogen, a substituent selected from a group consisting of the list α as defined below, or a lower alkyl which may optionally be substituted with a substituent selected from the group consisting of the list α as defined below,
• R4 and R5 may be same or different and each stands for hydrogen, a substituent selected from the group consisting of the list α as defined below, or a lower alkyl or lower cycloalkyl which may optionally be substituted with a substituent selected from the group consisting of the list α as defined below, or
• R4 and R5 together form, in combination with the carbon atom to which they bind, a 3–10 membered alicyclic group optionally having a hetero atom selected from a group consisting of nitrogen and oxygen, of the following formula [A]
• in which b is 0 or an integer of 1–4,
• R8 may be same or different where b is 2–4, and bind to optional atom(s) on the aliphatic ring, each standing for a substituent selected from the group consisting of the list α or a lower alkyl which may optionally be substituted with a substituent selected from the group consisting of the list α as defined below, or two R8's together form —NH—C(O)—O—CH2— or an oxo group,
• Y1 stands for —CH2—, —NR9— or —O—, where R9 stands for a substituent selected from a group consisting of hydrogen, optionally fluorine-substituted lower alkyl, lower alkylcarbonyl, lower alkyloxycarbonyl, lower alkylsulfonyl, carbamoyl, mono-lower alkylcarbamoyl and di-lower alkylcarbamoyl;
• [list α] wherein list α is
• halogen, hydroxyl, amino, mono-lower alkylamino, di-lower alkylamino, optionally fluorine-substituted lower alkyloxy, lower alkyloxycarbonyl, (lower alkyloxycarbonyl)amino, (lower alkyloxycarbonyl)lower alkylamino, carboxyl, lower alkylcarbonyl, lower alkylcarbonyloxy, (lower alkylcarbonyl)amino, (lower alkylcarbonyl)lower alkylamino, carbamoyl, mono-lower alkylcarbamoyl, di-lower alkylcarbamoyl, carbamoylamino, mono-lower alkylcarbamoylamino, di-lower alkylcarbamoylamino, (mono-lower alkylcarbamoyl)lower alkylamino, (di-lower alkylcarbamoyl)lower alkylamino, carbamoyloxy, mono-lower alkylcarbamoyloxy, di-lower alkylcarbamoyloxy, lower alkylsulfonyl, lower alkylsulfonylamino, sulfamoyl, mono-lower alkylsulfamoyl, di-lower alkylsulfamoyl, sulfamoylamino, (mono-lower alkylsulfamoyl)amino, (di-lower alkylsulfamoyl)amino, (mono-lower alkylsulfamoyl)lower alkylamino, (di-lower alkylsulfamoyl) lower alkylamino, phenyl tetrazolyl or oxadiazolyl which may optionally be substituted with lower alkyl,
• or their pharmaceutically acceptable salts.