title: Araiosamines A-D: tris-bromoindole cyclic guanidine alkaloids from the marine sponge Clathria (Thalysias) araiosa.
abstract: Four new tris-bromoindole cyclic guanidine alkaloids, araiosamines A-D, were isolated from the methanol extract of a marine sponge, Clathria (Thalysias) araiosa, collected from Vanuatu. Their carbon skeletons delineate a new class of indole alkaloids apparently derived from a linear polymerization process involving a carbon-carbon bond formation. Comparison of the structures including the relative configurations suggests a common intermediate containing a dihydroaminopyrimidine moiety capable of undergoing various modalities of conjugate addition to yield unprecedented ring systems.
authors.affiliation: Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wei
authors.forename: Niel M
authors.initials: NM
authors.lastname: Henriksen
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Skalicky
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Harper
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Cheatham
authors.forename: Chris M
authors.initials: CM
authors.lastname: Ireland
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Van Wagoner
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D006146:Guanidines / Q000737:chemistry* / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D008958:Models, Molecular; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry*; D012015:Reference Standards; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D006146:Guanidines