3-phenylpropanylcinnamate, a copolymer unit in Siegburgite fossil resin: aproposed marker for the Hammamelidaceae

Siegburgite, an unusual Tertiary aromatic resin found near Bitterfeld (Germ any), has been characterised earlier by FTIR spectrometry as polystyrene-li ke material. Here the molecular weight distribution of the soluble part is determined by size-exclusion chromatography (SEC) to be bomodal with maxima at 400 and 30.000 Da. Using combined gas chromatographic-mass spectrometri c techniques (GC-MS) traces of oleanonic and 3-epi-oleanolic acid are found in the low MW fraction of Siegburgite. 3-Phenylpropanylcinnamate is detect ed in the high MW fraction by pyrolysis (Py)-GC-MS. Although also present i n the soluble part of the high MW fraction, this compound is present especi ally in the insoluble residue, indicating that the ester is incorporated in the polymer chain. Oleanonic acid, 3-epioleanolic acid and 3-phenylpropany lcinnamate are constituents of commercially available Gum Storax from moder n Liquidambar. orientalis Mills. The proposed paleobotanical origin of Sieg burgite from the Hammamelidacae family is thus chemically confirmed. In add ition, a comparable polystyrene-like resin originating from North America ( Squankum New Jersey) was compared to Siegburgite. The polystyrene matrix of this resin is comparable to that of Siegburgite, but no molecular markers confirming its origin could be found. (C) 1998 Published by Elsevier Scienc e Ltd. All rights reserved.