Rare Earth Metal Cerium Salts-catalyzed Synthesis Of Nitrogen-containing Heterocyclic Compounds

Rare earth metal cerium, the highest abundance rare earth metal in nature, has been widely employed in various organic transformations. Nitrogen-containing heterocyclic compounds are an important class of heterocyclic chemistry. These kind of organic compounds possessing biological and pharmaceutical activities are widely found in nature, most of them bear nitrogen heterocyclic ring. The nitrogen-containing heterocyclic compounds can be modified easily structurally with diverse functional groups, which have widely applications in the fields of pharmacy, pesticide, dye, organometallic and photoelectric materials. Therefore, the design and synthesis of nitrogen-containing heterocyclic compounds have been attracting more and more interest of organic chemists. This thesis employs the efficient and commercial available cerium salts as Lewis acid catalyst to synthesis various nitrogen-containing heterocyclic compounds. The details are as follows:1. Cerium(IV) sulfate as catalyst in the three-component reaction of benzil or benzoin, ammonium acetate, and aromatic aldehydes, as well as in the four-component reaction of benzil, arylaldehydes, benzyl amine, and ammonium acetate under solvent-free conditions are explored. Solvent-free, simple work-up procedure, usage of low loading of catalyst and short reaction time are the highlights of this method.2. The carboxymethylcellulose supported cerium catalyst(CMC-CeIV) was prepared via metathesis of carboxymethylcellulose sodium with ceric ammonium nitrate(CAN) in aqueous solution. The catalyst was used to catalyze one-pot synthesis of 2,4,6-triarylpyridines under solvent-free condition. The products including 4 new compounds. The catalytic system has advantages of high catalytic activity, and easy recovery and recycling for the three-component reactions.