Uniquely modified imidazole alkaloids from a calcareous Leucetta sponge

Ruangelie Edrada-Ebel, Chad C Stessman, Phillip Crews

Research output: Contribution to journalArticle

78 Citations (Scopus)


A Fijian collection of the calcareous sponge Leucetta sp. was investigated and yielded four new imidazole alkaloids. One compound, (+)-calcaridine A (6), is unique in its overall structure and consists of a geminally substituted 2-aminoimidazolidinone. An additional compound, (-)-spirocalcaridine A (7), is distinctive in its hexahydrocyclopentamidazol-2-ylidenamine spiro-linked to a cyclohexenone. A third compound, (-)-spirocalcaridine B (8), is the OCH(3) analogue of 7. These compounds have unprecedented skeletons and functionality and are the first nonorganometalic chiral aminoimidazoles isolated from calcareous sponges. The two issues discussed here include the challenges associated with the structure elucidations of 6 and 7 and the relationships to previously encountered Leucetta metabolites.

Original languageEnglish
Pages (from-to)939-942
Number of pages4
JournalJournal of Natural Products
Issue number7
Early online date26 Jun 2003
Publication statusPublished - Jul 2003


  • alkaloids
  • animals
  • Fiji
  • imidazoles
  • molecular structure
  • biomolecular nuclear magnetic resonance
  • porifera
  • stereoisomerism


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