| abstract |
The invention relates to compounds represented by formula (I) and their salts: wherein R¹ represents hydrogen, lower alkyl, halogen, cyano or lower alkyloxycarbonyl, R² and R³ each represents hydrogen, lower alkyl, C₃-C₇ cycloalkyl or aryl or, when taken together, form piperadino or morpholino together with the adjacent nitrogen atom. These compounds scarcely emit fluorescence when present alone in an aqueous solution but, in the presence of a protein such as α₁-AG, they bind to the protein to emit strong fluorescence, thus being suitable reagents for determining proteins existing in a minute amount in blood, particularly α₁-AG. |