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 same meaning as R6, or binds to R6 to form a 3to 6membered ring together with the nitrogen atom to which they bind to form a saturated nitrogen containing cycloalkyl group or morpholino group, p in Rc is an integer of 2 to 4, A4 is a single bond or methylene or ethylene, A5 is