Synthesis and Antioxidant Activity of Securinine Derivatives

A series of 9-amino-14-oxa-7-azatetracyclo[6.6.1.01.11.02,7]pentadeca-11-en-13-ones were synthesized. The starting material was the natural alkaloid securinine, which underwent a Michael reaction with pharmacophoric tryptamines and substituted piperazines. The structure and stereochemistry of the previously unknown adduct with 5-methoxytryptamine were established using two-dimensional NMR experiments (COSY and NOESY). The biological activity of the synthesized securinine amino-derivatives was investigated. It was shown that several of the synthesized securinine conjugates exhibited antioxidant and iron-chelating activity and were interesting for further studies as potential pharmacologically active compounds.