Abstract: A fluorescent dye-forming composition is provided that contains a fluorescence-generating substrate of formula (I): where R1 and R2 are each independently a hydrogen atom, or an electron-donating group selected from a lower alkyl group, a lower alkoxy group, a hydroxyl group, an alkylcarbonyloxy group, an amino group di-substituted with a lower alkyl group, and an aryl group; L is selected from —NHCO— or —CONH—; Y is selected from -alkylene-COOH or formula (II):  where R3, R4 and R5 each independently represent a hydrogen atom, carboxyl group, or an electron-donating group selected from a lower alkyl group, a lower alkoxy group, a hydroxyl group, an alkylcarbonyloxy group, an amino group di-substituted with a lower alkyl group, and an aryl group. Alternatively, two of R3, R4 and R5 form, together with the adjacent carbon atoms to which they bond, a fused 5-membered or 6-membered hydrocarbon ring.

Abstract: Provided are methods for the synthesis of N-cyclic maleamic acids and N-cyclic maleimide derivatives, as well as N-cyclic maleamic acids and N-cyclic maleimides synthesized thereby. The method for synthesis of an N-cyclic maleamic acid involves reacting an amino group-containing N-cyclic compound with maleic anhydride in acetic acid to obtain an N-cyclic maleamic acid. An N-cyclic maleimide can be formed by adding hexamethyldisilazane to an N-cyclic maleamic acid prepared according to the above-described method, thereby cyclizing a maleamic acid site of the N-cyclic maleamic acid. The described methods allow for the products to be obtained at high yields.