Is there stereoselectivity in spin trapping superoxide by 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide?
Is there stereoselectivity in spin trapping superoxide by 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide?
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DOI：
10.1021/jo050692f
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发表时间：
2005-09-02
影响因子：
3.6
通讯作者：
Rosen, GM
中科院分区：
文献类型：
--
作者：
Tsai, P;Marra, JM;Rosen, GM
含酯的硝基化合物，包括5-叔丁基羰基-5-甲基-1-吡咯啉n -氧化物5，已被报道为超氧化物（O-2（中心点-））的强大自旋陷阱，使用手性柱，我们已经能够分离出硝基5的两个对映体。通过对映体纯硝基5a和5b，我们探索了这些同分异构体中的一个是否完全负责氨基6的EPR谱。结果表明，硝基酮5a和硝基酮5b对O-2（中心点-）的自旋俘获在均相水溶液中具有相同的EPR光谱和寿命，顺式和反式异构体的比例相同。真空中的量子化学模型也没有发现任何差异，除了预期的光学活性，引起立体化学的差异。
Ester-containing nitrones, including 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide 5, have been reported to be robust spin traps for superoxide (O-2(center dot-)), Using a chiral column, we have been able to isolate the two enantiomers of nitrone 5. With enantiomerically pure nitrone 5a and 5b we explored whether one of these isomers was solely responsible for the EPR spectrum of aminoxyl 6. Data obtained demonstrate that the spin trapping Of O-2(center dot-) by nitrone 5a and nitrone 5b affords the identical EPR spectra and lifetimes in homogeneous aqueous solution and exhibits the same ratio of cis and trans isomers. Quantum chemical modeling in vacuo also finds no difference, aside from the expected optical activity, arising from the difference in stereochemistry.