| abstract |
A piperazine derivative represented by the formula (1): n n nwherein n is an integer of 1 to 8; R 1 represents hydrogen or C 1-10 alkyl; A represents CH or nitrogen; Ar 1 represents phenyl or substituted phenyl; and Y represents a group represented by the formula Y 1 -Y 2 -Ar 2 or Y 3 -Y 4 (Ar 5 )-Ar 6 or a pharmaceutically acceptable salt of the derivative. The novel piperazine derivative has MC4 receptor antagonistic activity. |