The present invention offers compounds or their salts expressed by formula (I)(in the formula, X indicates an alkyl group, or the like； Y indicates an alkyl group； Z indicates a respectively independent nitro group, or the like； n indicates any integer from 0 to 3； A indicates carbon atom, or the like, and hydrogen atom is bonded thereto in the case where the carbon atom is not substituted with Z； D indicates oxygen atom, or the like； W indicates hydrogen atom, or the like； R1 and R2 indicate respectively independent hydrogen atoms, or the like； R1 and R2 may be bonded, and may form a heterocycle together with the nitrogen atom between R1 and R2).
