Pyridone derivatives having affinity for cannabinoid 2-type receptor

1. A method of binding a cannabinoid type 2 receptor, comprising bringing a cannabinoid type 2 receptor into contract with a compound of the formula (I):

wherein R 1 is hydrogen, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 each is independently single bond or optionally substituted alkylene; Y 2 is single bond, —O—, —O—C(═O)—, —O—C(═O)—O—, —O—C(═O)—NR b —, —O—SO 2 —, —NR b —, —NR b —C(═O)—, —NR b —SO 2 —, —NR b —C(═NH)—, —NR b —C(═O)—O—, —NR b —C(═O)—NR b —, —NR b —C(═O)—NR b —SO 2 —, —NR b —C(═S)—, —NR b —C(═S)—NR b —, —NR b —SO 2 —NR b —, —NR b —C(═NH)—NR b —, —S—, —SO 2 —O—, —SO 2 —NR b —, —SO 2 —NR b —C(═O)—NR b —, —C(═O)—O—, —C(═O)—NR b —, —C(═O)—NR b —C(═O)—, —C(═O)—NR b —C(═S)—, —C(═S)—NR b —, —C(═S)—NR b —C(═O)—, —C(═NH)—NR b —, —C(═O)—, —C(═O)—NR b —C(═NR b )—, or —C(═O)—NR b —NR b —; R a is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, or acyl; R b each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, acyl, hydroxy, or alkoxy;

R 2 is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 4 —R c wherein Y 4 is single bond, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH—, or —NH—C(═O)—; R c is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 3 and R 4 each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R d is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 5 is hydrogen, optionally substituted alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R e is optionally substituted carbocyclic group or optionally substituted heterocyclic group; or

any one of combinations of R 2 and R 3 , R 3 and R 4 , and R 4 and R 5 , taken together with the adjacent atoms form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

X is S or O;

provided that the case wherein R 3 and R 4 taken together with the adjacent atoms form benzene ring di-substituted with alkoxy, and R 5 is hydrogen or methyl is excluded;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

2. The method according to claim 1 wherein R 5 is optionally substituted C 2 or more alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 and R e are as defined in claim 1 .

3. The method according to claim 2 wherein R 5 is optionally substituted C 3 or more alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 is optionally substituted alkylene; R e is optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted heteroaryl, or optionally substituted heterocyclic group.

4. The method according to claim 1 wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 , Y 2 , Y 3 , R a , and R b are as defined in claim 1 .

5. The method according to claim 4 wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a ; Y 2 is —O—, —NR b —C(═O)— or —C(═O)—NR b —; R b is hydrogen or optionally substituted alkyl.

6. The method according to claim 1 receptor wherein R 3 and R 4 are not taken together.

7. The method according to claim 6 wherein R 3 is hydrogen, optionally substituted alkyl, halogen, or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond, optionally substituted alkylene, alkenylene, alkynylene; R d is optionally substituted aryl or optionally substituted heteroaryl;

R 4 is hydrogen or optionally substituted alkyl;

provided that the case wherein R 3 and R 4 are hydrogen at the same time is excluded.

8. The method according to claim 1 wherein R 3 and R 4 taken together with the adjacent atom form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

provided that the case wherein the optionally substituted cyclic group is optionally substituted benzene ring is excluded.

9. The method according to claim 1 wherein R 1 is hydrogen, cyano, formyl, carboxy, isothiocyanato, amino, hydroxy, carbamoyl, or a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 each is independently single bond or optionally substituted alkylene (the substituent is halogen, alkenylene, hydroxy, azide, amino, acylamino, alkylsulfonylamino, alkenyloxycarbonylamino, alkoxycarbonylamino, alkenylamino, arylcarbonylamino, heteroarylcarbonylamino, cyano, alkoxy, alkylsulfonyloxy, trialkylsilyloxy, oxo, methylene, halogenated alkoxycarbonyloxy formyloxy and/or acylthio); Y 2 is single bond, —O—, —O—C(═O)—, —O—C(═O)—O—, —O—C(═O)—NH—, —NH—, —NR b —C(═O)—, —NH—C(═O)—O—, —NH—C(═O)—NH—, —NH—C(═S)—NH—, —S—, —SO 2 —O—, —SO 2 —NH—, —SO 2 —NH—C(═O)—NH—, —C(═O)—O—, —C(═O)—NR b —, —C(═S)—NH—, —C(═O)—NH—C(═O)—, —C(═O)—NH—C(═S)—O—, —C(═O)—, —C(═O)—NR b —C(═NR b )—, or —C(═O)—NH—NR b —; R a is optionally substituted alkyl (the substituent is hydroxy and/or aralkyl), alkenyl, optionally substituted aryl (the substituent is carboxy, optionally substituted amino, alkoxy, alkylthio, alkylenedioxy, halogen, alkyl, hydroxy, halogenated alkyl and/or halogenated alkoxy), optionally substituted cycloalkyl (the substituent is aryl and/or hydroxy), optionally substituted cycloalkenyl (the substituent is alkenylene, hydroxy, alkylsulfonyloxy, azide, amino and/or acylamino), optionally substituted heteroaryl (the substituent is oxo, heteroaryl, halogen, aryl and/or alkyl), or optionally substituted heterocyclic group (the substituent is aryl optionally substituted halogen, aralkyl, acyl, arylcarbonyl, cycloalkylcarbonyl, alkylsulfonyl, arylsulfonyl, alkyl and/or halogenated alkylcarbonyl); R b is hydrogen, alkyl, acyl, hydroxy and/or alkoxy;

R 2 is hydrogen, alkyl, alkenyl, or a group represented by the formula: —Y 4 —R c wherein Y 4 is —O—; R c is heteroaryl;

R 3 is hydrogen, alkyl, halogen, or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond, alkylene, —C(═O)—NH-alkylene-; R d is optionally substituted aryl (the substituent is halogen, alkyl, alkoxy, alkylenedioxy and/or halogenated alkyl) or optionally substituted heteraryl (the substituent is halogen, alkyl, alkoxy, alkylenedioxy and/or halogenated alkyl);

R 4 is hydrogen or alkyl;

R 5 is hydrogen, optionally substituted C 3 or more alkyl which may have heteroatom and/or unsaturated bond (the substituent is halogen, hydroxy, azide, amino, alkoxy, alkenyloxy, alkylsulfonyloxy, acylthio, acylamino, arylcarbonylamino, cycloalkylcarbonylamino, halogenated alkylcarbonylamino, alkylsulfonylamino, arylsulfonylamino, formyl, oxo and/or cyano) or a group represented by the formula: —Y 6 —R e wherein Y 6 is alkylene; R e is optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted heteroaryl or optionally substituted heterocyclic group; or

R 2 and R 3 taken together with the adjacent atom form optionally substituted cyclic group (the substituent is oxo and/or hydroxy), R 3 and R 4 taken together with the adjacent atom form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond (the substituent is acyl, aralkyl, alkenylene and/or alkylene), or R 4 and R 5 taken together with the adjacent atom form optionally substituted carbocyclic group which may have unsaturated bond (the substituent is alkenylene).

10. A compound of the formula (I):

wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 , Y 2 , Y 3 and R b are as defined in claim 1 ; R a is optionally substituted carbocyclic group, optionally substituted heterocyclic group or acyl;

R 2 is hydrogen or optionally substituted alkyl;

R 3 is optionally substituted alkyl, halogen or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond or alkylene; R d is as defined in claim 1 ;

R 4 is hydrogen or optionally substituted alkyl;

R 5 is optionally substituted C 3 or more alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 and R e are as defined in claim 1 ; or

R 3 and R 4 taken together with the adjacent atom form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

X is as defined in claim 1 ;

provided that when R 3 and R 4 taken together with adjacent atom form optionally substituted benzene ring, R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 is single bond; Y 3 is optionally substituted alkylene; Y 2 is —NR b —C(═O)—, —C(═O)—NR b —; R a is optionally substituted carbocyclic group, optionally substituted heterocyclic group; and R b is hydrogen or optionally substituted alkyl; and

the followings are excluded: the case wherein R 3 and R 4 taken together with adjacent atom form unsubstituted carbocyclic group (provided that the bond between carbon atom substituted with R 3 and carbon atom substituted R 4 is the double bond, and the other bonds between carbon atoms are single bond), and R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 are single bond; Y 2 is —O—; R a is phenyl), and the case wherein R 3 and R 4 taken together with adjacent atom form benzene and R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein R 1 is single bond; Y 3 is ethylene; Y 2 is —C(═O)—NR b —; and R a is phenyl substituted with sulfamoyl;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

11. The compound according to claim 10 wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 , Y 3 , R a are as defined in claim 10 ; Y 2 is —O—, —NR b —C(═O)— or —C(═O)—NR b —; R b is hydrogen or optionally substituted alkyl;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

12. The compound according to claim 10 wherein R 3 and R 4 are not taken together;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

13. The compound according to claim 10 wherein R 3 and R 4 taken together with the adjacent atoms form cyclic group which may have heteroatom and/or unsaturated bond;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

14. The compound according to claim 10 wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 is single bond; Y 3 is optionally substituted alkylene; Y 2 is —O—, —NH—C(═O)—, or —C(═O)—NH—; R a is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 2 is hydrogen;

R 3 is alkyl, halogen or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond; R d is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 4 is hydrogen or alkyl;

R 5 is optionally substituted C 3 or more alkyl or a group represented by the formula: —Y 6 —R e wherein Y 6 is optionally substituted alkylene; R e is optionally substituted aryl, optionally substituted cycloalkyl or optionally substituted heteroaryl; or

R 3 and R 4 taken together with the adjacent atoms form cyclic group which may have heteroatom and/or unsaturated bond;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

15. A method of alleviating pain in a mammal, which comprises administering to the mammal a pharmaceutically effective amount of a compound of formula (I):

wherein R 1 is hydrogen, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 each is independently single bond or optionally substituted alkylene; Y 2 is single bond, —O—, —O—C(═O)—, —O—C(═O)—O—, —O—C(═O)—NR b —, —O—SO 2 —, —NR b —, —NR b —C(═O)—, —NR b —SO 2 —, —NR b —C(═NH)—, —NR b —C(═O)—O—, —NR b —C(═O)—NR b —, —NR b —C(═O)—NR b —SO 2 —, —NR b —C(═S)—, —NR b —C(═S)—NR b —, —NR b —SO 2 —NR b —, —NR b —C(═NH)—NR b —, —S—, —SO 2 —O—, —SO 2 —NR b —, —SO 2 —NR b —C(═O)—NR b —, —C(═O)—O—, —C(═O)—NR b —, —C(═O)—NR b —C(═O)—, —C(═O)—NR b —C(═S)—, —C(═S)—NR b —, —C(═S)—NR b —C(═O)—, —C(═NH)—NR b —, —C(═O)—, —C(═O)—NR b —C(═NR b )—, or —C(═O)—NR b —NR b —; R a is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, or acyl; R b each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, acyl, hydroxy, or alkoxy;

R 2 is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 4 —R c wherein Y 4 is single bond, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH—, or —NH—C(═O)—; R c is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 3 and R 4 each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R d is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 5 is hydrogen, optionally substituted alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R e is optionally substituted carbocyclic group or optionally substituted heterocyclic group; or

any one of combinations of R 2 and R 3 , R 3 and R 4 , and R 4 and R 5 , taken together with the adjacent atoms form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

X is S or O;

provided that the case wherein R 3 and R 4 taken together with the adjacent atoms form benzene ring di-substituted with alkoxy, and R 5 is hydrogen or methyl is excluded;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

16. A method of binding a cannabinoid type 2 receptor, comprising bringing a cannabinoid type 2 receptor into contact with a compound of the formula (I):

wherein R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 , Y 2 , Y 3 and R b are as defined in claim 1 ; R a is optionally substituted carbocyclic group, optionally substituted heterocyclic group or acyl;

R 2 is hydrogen or optionally substituted alkyl;

R 3 is optionally substituted alkyl, halogen or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond or alkylene; R d is as defined in claim 1 ;

R 4 is hydrogen or optionally substituted alkyl;

R 5 is optionally substituted C 3 or more alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 and R e are as defined in claim 1 ; or

R 3 and R 4 taken together with the adjacent atom form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

X is as defined in claim 1 ;

provided that when R 3 and R 4 taken together with adjacent atom form optionally substituted benzene ring, R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 is single bond; Y 3 is optionally substituted alkylene; Y 2 is —NR b —C(═O)—, —C(═O)—NR b —; R a is optionally substituted carbocyclic group, optionally substituted heterocyclic group; and R b is hydrogen or optionally substituted alkyl; and

the followings are excluded: the case wherein R 3 and R 4 taken together with adjacent atom form unsubstituted carbocyclic group (provided that the bond between carbon atom substituted with R 3 and carbon atom substituted R 4 is the double bond, and the other bonds between carbon atoms are single bond), and R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 are single bond; Y 2 is —O—; R a is phenyl), and the case wherein R 3 and R 4 taken together with adjacent atom form benzene and R 1 is a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein R 1 is single bond; Y 3 is ethylene; Y 2 is —C(═O)—NR b —; and R a is phenyl substituted with sulfamoyl;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.

17. A method of agonizing a cannabinoid type 2 receptor comprising bringing a cannabinoid type 2 receptor into contact with a compound of the formula (I):

wherein R 1 is hydrogen, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 1 —Y 2 —Y 3 —R a wherein Y 1 and Y 3 each is independently single bond or optionally substituted alkylene; Y 2 is single bond, —O—, —O—C(═O)—, —O—C(═O)—O—, —O—C(═O)—NR b —, —O—SO 2 —, —NR b —, —NR b —C(═O)—, —NR b —SO 2 —, —NR b —C(═NH)—, —NR b —C(═O)—O—, —NR b —C(═O)—NR b —, —NR b —C(═O)—NR b —SO 2 —, —NR b —C(═S)—, —NR b —C(═S)—NR b —, —NR b —SO 2 —NR b —, —NR b —C(═NH)—NR b —, —S—, —SO 2 —O—, —SO 2 —NR b —, —SO 2 —NR b —C(═O)—NR b —, —C(═O)—O—, —C(═O)—NR b —, —C(═O)—NR b —C(═O)—, —C(═O)—NR b —C(═S)—, —C(═S)—NR b —, —C(═S)—NR b —C(═O)—, —C(═NH)—NR b —, —C(═O)—, —C(═O)—NR b —C(═NR b )—, or —C(═O)—NR b —NR b —; R a is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, or acyl; R b each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclic group, optionally substituted heterocyclic group, acyl, hydroxy, or alkoxy;

R 2 is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro, or a group represented by the formula: —Y 4 —R c wherein Y 4 is single bond, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH—, or —NH—C(═O)—; R c is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 3 and R 4 each is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, halogen, cyano, formyl, acyl, carboxy, alkoxycarbonyl, optionally substituted carbamoyl, isothiocyanato, optionally substituted amino, hydroxy, alkoxy, alkylthio, alkenyloxy, alkynyloxy, alkylsulfinyl, alkylsulfonyl, nitro or a group represented by the formula: —Y 5 —R d wherein Y 5 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R d is optionally substituted carbocyclic group or optionally substituted heterocyclic group;

R 5 is hydrogen, optionally substituted alkyl which may have heteroatom and/or unsaturated bond or a group represented by the formula: —Y 6 —R e wherein Y 6 is single bond, optionally substituted alkylene, alkenylene, alkynylene, —O—, —S—, —SO—, —SO 2 —, —NH—, —C(═O)—, —CH 2 —, —C(═O)—NH-E-, or —NH—C(═O)—; E is single bond or optionally substituted alkylene; R e is optionally substituted carbocyclic group or optionally substituted heterocyclic group; or

any one of combinations of R 2 and R 3 , R 3 and R 4 , and R 4 and R 5 , taken together with the adjacent atoms form optionally substituted cyclic group which may have heteroatom and/or unsaturated bond;

X is S or O;

provided that the case wherein R 3 and R 4 taken together with the adjacent atoms form benzene ring di-substituted with alkoxy, and R 5 is hydrogen or methyl is excluded;

a prodrug, a pharmaceutically acceptable salt or solvate thereof.