Novel aminopyridine derivatives having selective inhibition of Aurora A

In the present invention, the general formula [I]: [wherein n1 and n2 are the same or different and are 0 or 1; R is an aryl group, heteroaryl group, etc .; Re is a hydrogen atom or lower An alkyl group; (i) one of Ra1 and Ra1 ′; (ii) one of Ra2 and Ra2 ′; (iii) one of Rb1 and Rb1 ′; and (iv) Rb2 and Rb2 ′. Or two groups selected from the group of four groups consisting of any one of:-(CH2) n- (wherein n is 1, 2 or 3). Among the Ra1 and Ra1 ′, Ra2, Ra2 ′, Rb1, Rb1 ′, Rb2 and Rb2 ′ that are formed and are not involved in the formation of — (CH2) n— are hydrogen atoms and the like; Rc, Rd and Re are hydrogen atoms and the like; X1, X2, X3, and X4 are each independently CH, N, etc .; Y1, Y2, and Y3 are the same or different, and are CH or N; W is a 5-membered aromatic heterocycle It is a ring. Or a pharmaceutically acceptable salt or ester thereof.