Abstract
The aim of this work was to identify characteristic fragments on mass spectrometra of both clerodane and 19-nor-clerodane-type diterpenes presenting and α,β-insaturated carbonyl moiety at ring A of the decalin-system. For that study, mass spectroscopy data were analysed for 19-nor-clerodanes [trans-dehydrocrotonin (1), trans-crotonin (2), cis-cajucarin B (3), trans-cajucarin B (4) and cajucarinolide (5)] and clerodanes [isosacacarin (6) and cajucarin A (7)] obtained from the stem bark of Croton cajucara Benth, and also clerodane-type from other species. The trans-junction of the enone-system clerodanes was clear correlated with the presence of the characteristic ions at m/z 95, 121 e 205. Meanwhile the characteristics ions at m/z 122 e 124 were correlated to cis-junction. The trans-junction of the enone-system 19-nor-clerodanes showed characteristics ions at m/z 161, 134 e 121.