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Oxidation of N-alkylpiperidines and other cyclic, tertiary amines with Hg(ll)-EDTA complex in basic solution yields lactams, similar oxidation of N-hydroxy-plperidines gives hydroxamic acids (presumably via nitrones) and oxidation of N-unsubstituted piperidines affords lactams, probably via 1-piperideine trimers.
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Wenkert et al. (1988) studied this question.
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