Lactam compounds and pharmaceutical use thereof

1. A compound of formula (I) or a pharmaceutically acceptable salt thereof:

wherein A represents an aromatic ring, a heterocyclic ring or an aliphatic ring; R 2 , R 3 and R 4 may be the same or different from one another and independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, a trifluoromethyl group, an alkenyl group which may have one or more substituents, an alkynyl group which may have one or more substituents, an aryl group which may have one or more substituents, a heteroaryl group which may have one or more substituents, a benzyloxyl group which may have one or more substituents, an aryloxyl group which may have one or more substituents, a heteroaryloxyl group which may have one or more substituents, an arylamino group which may have one or more substituents, an arylvinyl group which may have one or more substituents or an arylethynyl group which may have one or more substituents;

B represents a benzo group;

—X— and —Y— may be the same or different from one another and they independently represent —NH— or —NR 5 —, wherein R 5 represents a lower alkyl group which may have one or more substituents, an acyl group which may have one or more substituents, an alkoxycarbonyl group which may have one or more substituents, a carbamoyl group which may have one or more substituents, or a sulfonyl group which may have one or more substituents;

-Z- represents —CH 2 —, —C(O)—, or —CR 6 R 7 —, wherein R 6 and R 7 may be the same or different from each other and they independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group which may have one or more substituents, an aryl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, or a trifluoromethyl group;

—W— represents —NR 1 —, wherein R 1 represents a hydrogen atom, a lower alkyl group which may have one or more substituents or an aryl group which may have one or more substituents; and

a, b and c each represent the position of carbon atom,

wherein said one or more substituents is selected from the group consisting of a halogen atom, a hydroxyl group, an alkyl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, a trifluoromethyl group, an aryl group, and a heteroaryl group,

with the proviso that:

(i) when —X— and —Y— are each —NH—, -Z- is —CH 2 — and —W— is —NH—, then -A(R 2 )(R 3 )(R 4 ) cannot be a phenyl group, a 4-bromophenyl group, a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 2-hydroxyphenyl group, a 3,4-dimethoxyphenyl group, or a 3-methoxy-4-hydroxyphenyl group,

(ii) when —X— is —NH—, -Z- is —CR 6 R 7 — and —W— is —NH—, then both R 6 and R 7 cannot be a methyl group, and

(iii) when —X— is —NH—, -Z- is —C(O)— and —W— is —NR 1 —, then R 1 cannot be a p-tolyl group.

2. The compound or a pharmaceutically acceptable salt thereof according to claim 1 , wherein in formula (I),

A represents an aromatic ring, a heterocyclic ring or an aliphatic ring; R 2 , R 3 and R 4 may be the same or different from one another and independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, a trifluoromethyl group, an aryl group which may have one or more substituents, a heteroaryl group which may have one or more substituents, a benzyloxyl group which may have one or more substituents, an aryloxyl group which may have one or more substituents, a heteroaryloxyl group which may have one or more substituents, an arylamino group which may have one or more substituents, an arylvinyl group which may have one or more substituents or an arylethynyl group which may have one or more substituents;

—X— and —Y— may be the same or different from one another and they independently represent —NH— or —NR 5 —, wherein R 5 represents a lower alkyl group or an acyl group which may have one or more substituents;

-Z- represents —CH 2 —, —C(O)—, or —CR 6 R 7 —R 6 and R 7 may be the same or different from each other and they independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an aryl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group or a trifluoromethyl group;

wherein said one or more substituents is selected from the group consisting of a halogen atom, a hydroxyl group, an alkyl group, an aryl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, and a trifluoromethyl group,

with the proviso that:

(i) when —X— and —Y— are each —NH— and -Z- is —CH 2 —, then -A(R 2 )(R 3 )(R 4 ) cannot be a phenyl group, a 4-bromophenyl group, a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 2-hydroxyphenyl group, a 3,4-dimethoxyphenyl group, or a 3-methoxy-4-hydroxyphenyl group,

(ii) when —X— is —NH— and -Z- is —CR 6 R 7 —, then both R 6 and R 7 cannot be methyl group, and

(iii) when —X— is —NH— and -Z- is —CO—, then R 1 cannot be a p-tolyl group.

3. A compound or pharmaceutically acceptable salt thereof according to claim 1 , wherein in formula (I),

-Z- represents —CH 2 — or —CR 6 R 7 —, wherein R 6 and R 7 may be the same or different from each other and they independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a mercapto group, an alkoxyl group, an alkylthio group, an alkylsulfonyl group, an acyl group, an acyloxyl group, an amino group, an alkylamino group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group or a trifluoromethyl group and

—W— represents —NR 1 — wherein R 1 represents a hydrogen atom, a lower alkyl group which may have one or more substituents or an aryl group which may have one or more substituents.

4. A compound or a pharmaceutically acceptable salt thereof according to claim 3 , wherein

—Y— is —NR 5 —, wherein R 5 represents an acyl group having 1 to 7 carbon atoms which may have a substituent selected from the group consisting of a halogen atom, a lower alkyloxy group, a hydroxy group, a furyl group, a thienyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, a pyridyl group, a pyrimidyl group, and an imidazolyl group.

5. A compound or a pharmaceutically acceptable salt thereof according to claim 1 , wherein

A represents a 2-methoxyphenyl group;

—W—, —X—, and —Y— each represent —NH—; and

-Z- represents —CH 2 —.

6. A pharmaceutical composition, comprising a compound or pharmaceutically acceptable salt thereof according to claim 1 and a pharmaceutically acceptable carrier.

7. A method for treating hypoglycemia, comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 1 .

8. A method for treating diabetes, diabetic peripheral neuropathy, diabetic nephropathy, diabetic retinopathy, diabetic macroangiopathy, impaired glucose tolerance, or adiposis, said method comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 1 .

9. A pharmaceutical composition, comprising a compound or pharmaceutically acceptable salt thereof according to claim 2 and a pharmaceutically acceptable carrier.

10. A method for treating hypoglycemia, comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 2 .

11. A method for treating diabetes, diabetic peripheral neuropathy, diabetic nephropathy, diabetic retinopathy, diabetic macroangiopathy, impaired glucose tolerance, or adiposis, said method comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 2 .

12. A pharmaceutical composition, comprising a compound or pharmaceutically acceptable salt thereof according to claim 3 and a pharmaceutically acceptable carrier.

13. A method for treating hypoglycemia, comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 3 .

14. A method for treating diabetes, diabetic peripheral neuropathy, diabetic nephropathy, diabetic retinopathy, diabetic macroangiopathy, impaired glucose tolerance, or adiposis, said method comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 3 .

15. A pharmaceutical composition, comprising a compound or pharmaceutically acceptable salt thereof according to claim 4 and a pharmaceutically acceptable carrier.

16. A method for treating hypoglycemia, comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 4 .

17. A method for treating diabetes, diabetic peripheral neuropathy, diabetic nephropathy, diabetic retinopathy, diabetic macroangiopathy, impaired glucose tolerance, or adiposis, said method comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 4 .

18. A pharmaceutical composition, comprising a compound or pharmaceutically acceptable salt thereof according to claim 5 and a pharmaceutically acceptable carrier.

19. A method for treating hypoglycemia, comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 5 .

20. A method for treating diabetes, diabetic peripheral neuropathy, diabetic nephropathy, diabetic retinopathy, diabetic macroangiopathy, impaired glucose tolerance, or adiposis, said method comprising administering to a subject in need thereof an effective amount of a compound or pharmaceutically acceptable salt thereof according to claim 5 .