Irigermanal and Iridogermanal: Two New Triterpenoids from Rhizomes of Iris germanica L.

Article abstract of DOI:10.1021/jo00134a007

α-Irigermanal (8a), γ-irigermanal (8b), and iridogermanal (12) are the major extractable lipids of the rhizomes of Iris germanica, constituting about 1percent of their fresh weight.The structure of the compounds was determined by detailed spectral analysis, chemical degradation, and X-ray crystallography. 8b crystallizes as a methanol solvate in the space group P2₁ with a = 13.05 (1) Angstroem, b = 8.84 (2) Angstroem, c = 13.78 (1) Angstroem, β = 105.84 (5) deg, and Z = 2.The irigermanals are the first known bicyclic triterpenoids, and iridogermanal is the firstmonocyclic triterpenoid found so far.The compounds are closely related to ambreine.