Synthesis and Reduction Kinetics of Sterically Shielded Pyrrolidine Nitroxides

A series of sterically shielded pyrrolidine nitroxides were synthesized, and their reduction by ascorbate (vitamin C) indicate that nitroxide 3, a tetraethyl derivative of 3-carboxy-PROXYL, is reduced at the slowest rate among known nitroxides, i.e., at a 60-fold slower rate than that for 3-carboxy-PROXYL.本研究合成了一系列空间位阻屏蔽的吡咯烷氮氧自由基（sterically shielded pyrrolidine nitroxides），经抗坏血酸盐（维生素C）还原实验表明，作为3-羧基-PROXYL四乙基衍生物的氮氧自由基3，是目前已知氮氧自由基中还原速率最慢的，其还原速率较3-羧基-PROXYL慢60倍。