A flavone fluorescent probe for cysteine detection

A new blue-emitting fluorescent probe 1 based on flavone structure was prepared for the selective detection of cysteine. The probe was prepared through three synthetic steps from commercially available starting materials. Selective detection of cysteine by probe 1 in the presence of other non-thiol amino acids was established by UV-visible and fluorescent experiments. A remarkable fluorescence emission was observed at 469 nm when cysteine was mixed with probe 1. The Michael addition reaction of cysteine to probe-1 was confirmed by ¹H NMR technique.