Hesperathusa crenulata

Many coumarins may be purified by high vacuum sublimation, but this should be avoided in work with potentially new coumarins. Alloisoimperatorin (291) is probably an artefact from thermal rearrangement of the prenyl ether, isoimperatorin (254) 153), while angelical (80) is now known to arise from thermal degradation of angelol (98) 253). It is not yet known whether crenulatin [ = angelical, (80)], recently isolated from Hesperathusa crenulata, is also an artefact. 

Basa, S. C. Crenulatin, a Formyl Coumarin from Hesperathusa crenulata (Rutaceae). Austral. J. Chem. 28, 1159 (1975). 

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