The EI‐MS Fragmentation Mechanisms of the Bacterial Diterpenes Polytrichastrene A and Wanju‐2,5‐diene.

The fragmentation mechanisms leading to the formation of several pronounced fragment ions formed during EI mass spectrometry of the diterpene hydrocarbons polytrichastrene A and wanju‐2,5‐diene were investigated by isotopic labelling experiments. All twenty singly 13C‐labelled isotopomers of these diterpenes were enzymatically synthesised from the twenty isotopomers of (13C)geranylgeranyl diphosphate using the polytrichastrene synthase from Chryseobacterium polytrichastri. Their mass spectrometric investigation allowed for conclusions on the fragmentation mechanisms leading to the observed fragment ions. [ABSTRACT FROM AUTHOR]