Design, Synthesis And Spectra Research Of Fluorescent Sensors With 2-Imino-thiazolidine (Oxazolidine) As Receptors

A series of 1,8-naphthalimides and naphthalenes derivatives with 2-imino-thiazolidine (oxazolidine) as receptors were designed and synthesized, which were used as medium of synthesizing complicated fluorescent probes. The fluorescent recognition of the probes to proton, cations and certain enzymes were studied.A series of novel 4-piperidine- 1,8-naphthalimides derivatives with 2-imino-thiazolidine (oxazolidine) as proton receptors were designed and synthesized. It was found that 2a-l, 2a-3, 2as-l, 2as-3 and 2as-6 exhibited strong fluorescent pH-sensing based on intramolecular hydrogen bonding abilities of naphthalimide and 2-imino-thiazolidine (oxazolidine), which might provide a novel method to study certain bioprocesses involved in hydrogen bond. The results also proved that when 4-piperidine functional group was replaced by 4-morpholine (pyrrolyl, N,N-dimethyl-amino), no fluorescent pH response was observed.A series of novel 1-8-naphthalimides and naphthalene derivatives with 2-imino-thiazolidine (oxazolidine) as Fe(III) receptors were designed and synthesized, among which 3a, 3b, 3c-1, 3c-3 and 3c-4 selectively exhibited strong fluorescence quenching (90% quenching) in the presence of Fe(III) in Tris-HCl buffers and were not affected by the presence of other cations (such as: Hg²⁺, Cd²⁺, Zn²⁺, NH₄⁺, Li⁺, Na⁺, Mg²⁺, K⁺, Ca²⁺, Co²⁺, Ni²⁺, Al³⁺, Cr³⁺, Cu²⁺). Meanwhile, A series of bi-1,8-naphthalimides derivatives with 2-imino-thiazolidine (oxazolidine) as receptors were designed and synthesized. This kind of probes is PET system with fluorescent switch for complicated recognition system.A series of 1,8-naphthalimides derivatives with 2-imino-thiazolidine (oxazolidine) or isothiourea as certain enzyme receptors were designed and synthesized. Some of the compounds were selected to study their fluorescent shifts in the presence of trehalase, thombin, NOS or trypsin, among which 4b-4, 4b-1 and 4c-2 selectively or high selectively responded to trehalase. The results showed that it was possible to selectively or specifically fluorescent sensing of certain hydrolase by enzyme-inhibitor interactions, which might be further applied in biochemistry, medicinal and pesticidal chemistry.