Edrada Ru Angelie, Stessman Chad C, Crews Phillip
Department of Chemistry and Biochemistry and Institute for Marine Sciences, University of California, Santa Cruz, California 95064, USA.
J Nat Prod. 2003 Jul;66(7):939-42. doi: 10.1021/np020503d.
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.
对斐济采集的钙质海绵Leucetta sp.进行了研究，从中分离出四种新的咪唑生物碱。一种化合物，(+)-卡尔卡里定A（6），其整体结构独特，由偕二取代的2-氨基咪唑烷酮组成。另一种化合物，(-)-螺旋卡尔卡里定A（7），其独特之处在于与环己烯酮螺环相连的六氢环戊并咪唑-2-亚基胺。第三种化合物，(-)-螺旋卡尔卡里定B（8），是7的OCH(3)类似物。这些化合物具有前所未有的骨架和官能团，是首次从钙质海绵中分离得到的非有机金属手性氨基咪唑。这里讨论的两个问题包括与6和7的结构解析相关的挑战以及与之前发现的Leucetta代谢产物的关系。
