be substituted with one of T1 or two or more of the same or different T1, and bind to A6 at an arbitrary position on the ring), R4 and R6 independently represent hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, R5 and R7 independently represent hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, orA6Qa, R8 is a lower alkyl group having 1 to 4 carbon atoms, R6'has the sa