Pumiliotoxin-B and Some of its Isomeric Structures - A DFT Study

Abstract

Pumiliotoxin-B is an alkaloid produced by dart-poison frogs which are colorful and petite amphibians native to Caribbean region. In the present density functional treatment at the level of B3LYP/6-31G(d), pumiliotoxin-B and some of its isomeric structures are considered. Some structural and molecular orbital characteristics of them are investigated. These isomeric structures of pumiliotoxin-B include the enol and keto tautomers as well as the epoxide built on the double bond having E configuration. The calculations have indicated the enol form to be more stable than the keto form, which might be attributed to possibility of more and better hydrogen bonding facility in the enol form. Another striking result obtained by both the thermodynamic and molecular orbital calculations is that the enol form is more stable than pumiliotoxin-B in vacuum conditions.