Study On Tandem Synthesis Of Substituted Triazines,Pyrroles And Triazoles Compounds

The exploration of the synthesis of new-type heterocycles and its pharmacological activities are hot topics of the current heterocyclic chemistry. Beside this, Nitrogen-contained heterocycles are used widespread in physiology, pharmacology, farm chemical and functional materials, so the chemists pay much attention to the new synthetic methods of N-heterocycles. In the presenting dissertation, we summarized the metal-catalyzed direct C-H aminations, then investigated copper or triphenylphosphine catalyzed multicomponents tandem reactions involving N-contained substrates to afford heterocycles, which include:1. Copper-catalyzed N-Tosylaziridines and Hydrazones to approachtetrahydrotriazines.We developed a single-step approach to tetrahydrotriazines in good yield via the Cu(OTf)2-catalyzed tandem reaction of N-Tosylaziridines and Hydrazones. The process is thought to involve a lewis-acid catalyzed nucleophilic ring-opening reaction and a copper-catalyzed direct intramolecular C-H animation. Because of its mild conditions, conciseness and atom economy, this procedure may afford a new and efficient method to medicinal chemistry based on the triazines.2. Copper-catalyzed a-diazoketones, Nitroalkenes and Amines to approach pyrroles.We developed a CuOTf-catalyzed three-components synthesis of polysubstituted pyrroles from a-diazoketones, Nitroalkenes and Amines. This reaction is good in universality, all kinds of substituted diazoketones, nitroalkenes and benzyl amine or π-conjugated primary amine can afford corresponding products. We also proposed a possible mechanism for this multicomponent tandem reaction. The result products can be easily transformed to polycyclic conjugated compounds. Thus we developed a new way for metal-catalyzed synthesis of pyrrole compounds.3. Triphenylphosphine-triggered azidoacrylates and azodicarboxylates to synthesis1,2,4-triazolines.We developed a facile synthesis of1,2,4-triazolines via PPh3-triggered reaction of azidoacrylates and azodicarboxylates. In the reaction, Staudinger-Meyeris reaction between PPh3and azidoacrylates is replaced by the formation of Huisgen zwitterions from PPh3and dialkyl azodicarboxylates, followed by a Micheal-type addition and a Curtius-type rearrangement, the cyclic products were obtained in good yield. The major features of this procedure include mild conditions; metal-free; N2as the only by-product; the use of catalytic amount of PPh3which is a development to the Huisgen zwitterions reation.