| abstract |
The present invention relates to a compound represented by a formula (I): or a pharmaceutically acceptable salt thereof, wherein R 1 represents lower alkyl or the like; R 2 represents phenyl or the like; R represents a halogen atom or the like; X represents an oxygen atom or the like; Y 1 , Y 2 , Y 3 and Y 4 represent CH or the like; l represents an integer of from 0 to 3; m and n each represent an integer of 1 or 2; p represents an integer of from 0 to 2; and q represents an integer of from 1 to 3. |