3-(4-aminophenyl)-2-furancarboxylic acid derivative and pharmaceutically acceptable salt thereof

A compound represented by Formula (II) or a pharmaceutically acceptable salt thereof:

• wherein A is one member selected from the group consisting of groups represented by Formulae (a) to (d) below:
• wherein R12a, R12b, and R12c are the same or different, and independently represent:
• 1:
• a hydrogen atom,
• 2:
• a halogen atom,
• 3:
• a C1-4 alkyl group, which is optionally substituted with 1 to 3 fluorine atoms,
• 4:
• a C1-4 alkoxy group, which is optionally substituted with 1 to 3 fluorine atoms, or
• 5:
• a C1-4 alkylcarbonyl group, which is optionally substituted with C1-4 alkoxy;
• R12d, R12e, and R12f are the same or different, and independently represent:
• 1:
• a hydrogen atom,
• 2:
• a halogen atom, or
• 3:
• C1-4 alkyl;
• and
• R22 is a cyano group or a nitro group.

A compound represented by Formula (III) or a pharmaceutically acceptable salt thereof:

• wherein R13a, R13b, and R13c are the same or different, and independently represent:
• 1:
• a hydrogen atom,
• 2:
• a halogen atom,
• 3:
• a C1-4 alkyl group, which is optionally substituted with 1 to 3 fluorine atoms, 4:
• a C1-4 alkoxy group, which is optionally substituted with 1 to 3 fluorine atoms, or 5:
• a C1-4 alkylcarbonyl group, which is optionally substituted with C1-4 alkoxy.

A method for producing a compound represented by Formula (I) or a pharmaceutically acceptable salt thereof:

• wherein R1 is
• 1:
• a C3-8 cycloalkyl C1-4 alkyl group,
• 2:
• a C7-14 aralkyl group, in which the aryl moiety thereof is optionally substituted with the same or different 1 to 3 groups selected from the group consisting of:
• (a) halogen,
• (b) C1-4 alkyl, which is optionally substituted with 1 to 3 fluorine atoms,
• (c) C1-4 alkoxy, which is optionally substituted with 1 to 3 fluorine atoms, and
• (d) C1-4 alkylcarbonyl, which is optionally substituted with C1-4 alkoxy,
• 3:
• a five- to ten-membered heteroaryl-C1-4 alkyl group, in which the heteroaryl moiety thereof is optionally substituted with the same or different 1 to 3 groups selected from the group consisting of:
• (a) halogen, and
• (b) C1-4 alkyl;
• or
• 4:
• a C6-10 aryl C2-6 alkenyl group;
• and
• R2 is a cyano group or a nitro group;
• the method comprising the step of reacting a compound represented by Formula (IV):
• wherein R14 is the same as R1 above, Y is a group:
• —COOR9 or a group:
• —CONHNH2, and R9 is a hydrogen atom or a C1-6 alkyl group, with a compound represented by Formula (K):
• wherein R2 is as defined above, and R8 is a hydrogen atom, a Ci-4 alkyl group, a C1-4 alkoxy C1-4 alkyl group, a C6-10 aryl group, a C7-14 aralkyl group, or a C1-4 alkylcarbonyl group;
• and, as necessary, converting the reaction product to a pharmaceutically acceptable salt.

A compound represented by Formula (IV) below or a pharmaceutically acceptable salt thereof:

• wherein R14 is
• 1:
• a C3-8 cycloalkyl C1-4 alkyl group,
• 2:
• a C7-14 aralkyl group, in which the aryl moiety thereof is optionally substituted with the same or different 1 to 3 groups selected from the group consisting of:
• (a) halogen,
• (b) C1-4 alkyl, which is optionally substituted with 1 to 3 fluorine atoms,
• (c) C1-4 alkoxy, which is optionally substituted with 1 to 3 fluorine atoms, and
• (d) C1-4 alkylcarbonyl, which is optionally substituted with C1-4 alkoxy,
• 3:
• a five- to ten-membered heteroaryl-C1-4 alkyl group, in which the heteroaryl moiety thereof is optionally substituted with the same or different 1 to 3 groups selected from the group consisting of:
• (a) halogen, and
• (b) C1-4 alkyl, or
• 4:
• a C6-10 aryl C2-6 alkenyl group;
• Y is a group:
• —COOR9 or a group:
• —CONHNH2;
• and
• R9 is a hydrogen atom or a C1-6 alkyl group.