Irigermanone, a noriridal with unprecedented methylketone function, from iris germanica

Abstract

A new iridal, irigermanone (1) and nine known congeners, 2-10, respectively, have been isolated from the dried rhizomes of German iris (Iris germanica). The structure of 1 was established by spectroscopic methods including HR-ESI-MS, 1D- and 2D-NMR, and electronic circular dichroism (ECD) spectroscopy. Compound 1 is a structurally unique noriridal, and it possesses an unprecedented methylcarbonyl group instead of the α,β-unsaturated aldehyde function typical for this group of triterpenes. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.