The present invention aims to provide a novel compound for measuring
cellular cytotoxicity or
cell proliferation capacity accurately with high reproducibility, conveniently and rapidly, and a measurement method of
cellular cytotoxicity or
cell proliferation capacity by using the compound. The present invention relates to a compound represented by the formula (I):wherein R1 is a
substituent, R2 and R3 are each an optionally substituted
hydrocarbon group, or an optionally substituted heterocyclic group, Y is a
substituent, n is an integer of 0-3, Z is a
single bond, —O—, —S—, —SO—, —SO2—, or —NR4— (R4 is a
hydrogen atom or a
substituent), and A is an optionally substituted C1-6 alkylene group) or a salt thereof.