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[摘要]:We have achieved an efficient alternative synthesis of blood-brain-barrier permeable nitroxyl radicals 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (1a) and 3-ethoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (1b), which affords la and 1b in 65% isolated yields by four steps from 2,2,6.6-tetramethyl-4-piperidone (2), respectively. This protocol is applicable to the synthesis of 3-isopropoxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (1c) and 3-carbonyl-2,2,5,5-tetramethylpyrro-lidine-1-oxyl (6). |
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