Copper-Catalyzed N-Alkylation Of Nucleobases Involving Direct Functionalization Of Sp~3C-H Bonds αto Oxygen Atoms

Aiming at two kinds of heterocycles which are important scoffolds in Pharmaceuticals, this thesis reports two novel synthetic methods by using a series of simple and easily available materials. The thesis can be divided into two parts:First, the study of copper-catalyzed N-alkylation of nucleobases involving directfunctionalization of sp3C-H bonds a to oxygen atoms. N-alkylated nucleobases represent core structures in many biologically active analogues of natural nucleosides. They are also the basic scaffold in a variety of chain-termination reagents used in the DNA sequencing. In this chapter, we have developed a new method for the preparation of N-alkylated nucleobases by the direct reaction between ethers and nucleobases. After the optimization of the reaction conditions that containing the ligands, catalysts, concentration, temperature and reaction time, an optimized condition has been achieved by which various nucleobases can react with various ethers in moderate to good yields. Based on these researches, a plausible reaction mechanism has been proposed.Second, a new method for the preparation of1,4,7,10-tetraazacyclododecane utilizing vinyl sulfonium as a key substrate has been reported.1,4,7,10-tetraazacyclododecane is important intermediate in the synthesis of many MIR reagents. This part has developped a novel method for the synthesis of this intermediate.