摘要:
The present invention provides a novel dihydroorotic acid dehydrogenase inhibitor which is applicable to various diseases. When used as an active ingredient, a compound represented by formula (I): (wherein X represents a halogen atom, R 1 represents a hydrogen atom, R 2 represents an alkyl group containing 1 to 7 carbon atoms, R 3 represents -CHO, and R 4 represents -CH 2 -CH=C(CH 3 )-R 0 (wherein R 0 represents an alkyl group containing 1 to 12 carbon atoms which may have a substituent on the terminal carbon and/or on a non-terminal carbon, etc.)), an optical isomer thereof or a pharmaceutically acceptable salt thereof has a high inhibitory effect on dihydroorotic acid dehydrogenase and can be used as an immunosuppressive agent, a therapeutic agent for rheumatism, an anticancer agent, a therapeutic agent for graft rejection, an antiviral agent, an anti- H . pylori agent, a therapeutic agent for diabetes or the like.