Patent ID: 7879887

Claim:
An α-Amino acid derivative of formula (1): wherein, R 1 represents a hydrogen atom, R 2 and R 3 each independently represent a hydrogen atom; a C 1-4 alkyl group optionally substituted with a substituent(s) selected from the group consisting of a hydroxyl group, C 1-4 alkoxy group, benzyloxy group, —CONH 2 group and phenyl group; or phenyl group, or R 2 and R 3 together form —(CH 2 ) n —, wherein n represents an integer of 2, 3, 4 or 5, or R 2 and R 3 form C═O together with a carbon atom to which they are attached, R 4 represents a hydrogen atom, or R 4 and R 2 together form —(CH 2 ) m —, wherein m represents an integer of 1, 2, 3 or 4, Y represents a C 6-10 aryl group or C 4-9 heterocyclic group optionally substituted with substituents R 5 , R 6 and R 7 , wherein, the substituents R 5 , R 6 and R 7 each independently represent: a hydrogen atom; halogen atom; hydroxyl group; nitro group; cyano group; formyl group; —NHCOR 11 , wherein, R 11 represents a hydrogen atom, C 1-4 alkyl group, C 3-6 cycloalkyl group, amino group, C 1-4 alkylamino group, di-C 1-4 alkylamino group or C 1-4 alkoxy group optionally substituted with a hydroxyl group(s); —SO 2 NH 2 , —SO 2 NHR 12 , —SO 2 NR 12 R 13 or —NHSO 2 R 12 , wherein, R 12 and R 13 each independently represent a C 1-4 alkyl group; amino group; —CONH 2 ; —CO 2 H; C 1-4 alkylamino group, di-C 1-4 alkylamino group, C 1-4 alkylaminocarbonyl group or di-C 1-4 alkylaminocarbonyl group, wherein, these groups may be optionally substituted with a substituent(s) selected from the group consisting of —CONH 2 , —SO 2 NH 2 , —CO 2 H and a C 1-4 alkoxycarbonyl group optionally substituted with a hydroxyl group(s); C 3-6 cycloalkylaminocarbonyl group; benzyloxyaminocarbonyl group; C 1-4 alkoxyaminocarbonyl group; N—C 1-4 alkoxy-C 1-4 alkylaminocarbonyl group; C 1-4 alkyl group, C 1-4 alkoxy group or C 1-4 alkoxycarbonyl group, wherein, these groups may be optionally substituted with a substituent(s) selected from the group consisting of a halogen atom, hydroxyl group, —CONH 2 , —SO 2 NH 2 and —CO 2 H; or 5- to 6-membered monocyclic heterocyclic group containing 1 to 3 nitrogen atoms; and X represents a group of formula (2): wherein, R 8 , R 9 and R 10 each independently represent: a hydrogen atom; halogen atom; C 1-4 alkoxycarbonyl group; —CO 2 H; nitro group; or C 1-4 alkyl group optionally substituted with a substituent(s) selected from the group consisting of a halogen atom, hydroxyl group, C 1-4 alkoxy group, C 1-4 alkoxycarbonyl group and —CO 2 H, or a tautomer thereof; or a pharmaceutically acceptable salt thereof.