Synthesis of N-(9-acridinyl)maleimide, a fluorometrical reagent for thiol compounds.

The authors have reported) a new maleimide type fluorescent thiol reagent, N-(9-acridinyl)-maleimide (NAM). In this paper the syntheses of NAM and its coupling products with thiol compounds are presented. NAM was synthesized from 9-aminoacridine and maleic an-hydride through dehydratic cyclization in polyphosphoric acid. NAM showed no sub-stantial fluorescence but its coupling products with thiol compounds exhibited strong blue fluorescence. Application of NAM for the fluorometrical analysis of cysteine and glutathione are suggested.