Patent ID: 8436009

Claim:
A compound represented by the following Formula (I) or a pharmaceutically acceptable salt thereof: wherein R 1 represents phenyl optionally substituted by one to three C 1 -C 6 alkyl groups, C 1 -C 6 alkoxy or C 2 -C 6 alkenyloxy; R 2 represents a hydrogen atom, C 1 -C 6 alkylcarbonyl or pyridylcarbonyl; R 3 and R 4 each independently represent a hydrogen atom or C 1 -C 6 alkyl; A represents a single bond, an oxygen atom, a group represented by Formula (II): wherein R a and R b each independently represent a hydrogen atom or C 1 -C 6 alkyl, and *1 and *2 mean linking to carbonyl and to R 5 , respectively, in Formula (I), or a group represented by Formula (III): wherein R c , R d , R e and R f each independently represent a hydrogen atom or C 1 -C 6 alkyl, and *1 and *2 have the same meanings as described above; and R 5 represents C 1 -C 6 alkyl or C 3 -C 8 cycloalkyl, and C 1 -C 6 alkyl or C 3 -C 8 cycloalkyl in R 5 is optionally substituted by one to three identical or different substituents selected from the group of substituents consisting of a halogen atom, C 1 -C 6 alkyl and C 1 -C 6 alkoxy.