Abstracts - Daiane Szczerbowski


Daiane Szczerbowski[1,2], Michael Kostka[1], Paulo Henrique Gorgatti Zarbin[2], Miguel Vences[3] and Stefan Schulz[1,*].

1 Institut für Organische Chemie,Technische Universität Braunschweig, Germany
2 Departamento de Química, Universidade Federal do Paraná, Brazil
3 Zoologisches Institut, Technische Universität Braunschweig, Germany;
* Correspondence: stefan.schulz@tu-bs.de

Several anurans present a powerful chemical arsenal in the skin to use as protection against bacteria and fungus. Poison frogs are anuran species characterized to possess alkaloids in their skin secretions and present the capacity to sequester this defense compounds from the diet of arthropods, usually ants and mites.[1] The specie Eleutherodactylus iberia was the most recent one to have this capacity identified. In previous work, alkaloids were identified in skin extracts of E. iberia, but two piperidinic alkaloids of novel structure were still unrevealed.[2] In the present work, analysis of the mass spectra allowed structural proposes for these unknown compounds, these being 9-(1,6-dimethylpiperidin-2-yl)nonane-2-ol (1) and 9-(1,6-dimethylpiperidin-2-yl)nonane-1,2-diol (2). The retrosynthetic analysis (Scheme 1) lead to a strategy for the synthetic route of these compounds. The key step of the synthesis was the Beckmann rearrangement that was performed in one step from the oxime, forming the mesylate that was not isolated and was reacted directly to form the piperidinic ring. After the synthesis of the two proposed structures, they presented mass spectra very similar with the ones from the natural extract. This is the first description of N-methylated alkaloids in the anuran family.

Scheme 1: Retrosynthetic analysis for the synthesis of alkaloids 1 and 2
1. Daly, J. W., J. Nat. Prod. 61, 162, 1998.
2. Rodríguez, A. et al., Mol. Phylogenet. Evol. 68, 541, 2013.