Design, Synthesis And Application Of Bifuctional Chiral Thioureas, Squaramides And Tryptanthrin Derivatives

Chiral organic catalysts, due to simplicity, effectivity and stability towards water andoxygen, have been widely applied in the field of asymmetric synthesis over the pastdecade. Chiral thioureas and squaramides, which are used as a new class of chiral organiccatalysts, can activate substrates and control stereoselectivity by hydrogen-bondingsinteraction with substrates in asymmetric reactions. So, this kind of chiral organic catalystshave shown excellent asymmetric catalytic activity and stereoselectivity in a variety ofsymmetric catalytic reactions. Especially, bifuctional chiral thioureas and squaramides,which combine hydrogen-bonding donors with basicity or phase-transfer catalytic activityetal, have been focused by organic chemists.In recent years, organic molecular fluorescent probes, due to their structuralsimplicity, easy design and synthesis, have become one of most popular research onfluorescent dyes. Design and synthesis of organic molecular fluorescent probes, whichhave good specificity, high sensitivity and strong anti-interference ability, is one of hottopics. Tryptanthrin widely exists in the nature. The hydrazone derivatives derived fromtryptanthrin and phenylhydrazine can effectively recognize corresponding anions by theN—H···N hydrogen-bondings interaction.In this thesis, relative research work on bifunctional chiral thiourea and squaramidecatalysts, and organic molecular fluorescent probes is as follows:(1) We synthesized two new chiral thiourea catalysts using cinchonine as chiralcompound and several reactions such as meysalation, the nucleophilic substitution ofsodium azide, the reduction of azide compound and the nucleophilic addition of amine andisothiocyanate. All of intermediates and target molecules were characterized by1H NMRand13C NMR.(2) A novel kind of chiral squaramide catalysts was synthesized via the nucleophilicsubstitution of compounds3-4, derived from L-tert-leucine and3-6. Compounds3-4and3-6were prepared via a multi-step reaction, respectively. All of intermediates and targetmolecules were characterized by1H NMR and13C NMR.(3) In order to envaluate the asymmetric catalytic activity of bifunctional chiral catalystssuch as chiral thioureas, squaramides and other catalysts which were prepared earlier in our laboratory, we chose1,3-dipolar cyclic addition of N-hydroxybenzimidoyl chlorideand ethyl2-(4-methoxyphenylimino)acetate as the model reaction.Experimental resultsshowed that bifunctonal chiral thiourea and guanidine catalysts exhibited a certaincatalytic activity and obtained corresponding products in moderate yields, but ee values ofproducts were low. In comparison, chiral thioureas derived from (R)-binaphthol and (R,R)-trans-1,2-diamiocyclohexane have a little higher asymmetric activity, especially, chiralthioureas synthesized from (R, R)-trans-1,2-diamiocyclohexane exhibited a certainstereoselectivity.(4) A Tryptanthrin derivative was synthesized by the reaction of tryptanthrin withPhenylhydrazine. In DMF, with the addition of F-, AcO-and H2PO4-, the“yellow-to-orange” change could be observed by naked eyes. Meanwhile, there were nochanges when other anions (Cl-, Br-, I-, ClO4-, NO3-and HSO4-) were added. And this newanions probe based on tryptanthrin derivative was first reported. The1H NMR titrations ofthis anions probe indicated that the “yellow-to-orange” response was triggered by thehydrogen bonding interaction between NH with F-, AcO-and H2PO4-. Then a novelfour-input molecular logic gate was designed.