title: Asmarines A-F, novel cytotoxic compounds from the marine sponge Raspailia species.
abstract: Three pairs of nitrogen-containing metabolites, asmarines A-F (1-6), were isolated from the Red Sea sponge Raspailia sp., collected in the Dahlak Archipelago, Eritrea. Although the first pair could fully be separated to give compounds 1 and 2, the other two pairs could only be enriched up to about 80% of one isomer. The structures of the new compounds were established by spectroscopic means. Besides the asmarines, methyl 3-oxo-cholan-24-oate (12) was also isolated. The absolute configuration of asmarine A (1) was determined on the basis of CD measurements of its unstable 18-oxo derivative (7) and mainly the Cotton effect of the dicarbonyl derivative (9) of chelodane (8). A O,N(7')-dimethyl derivative (10) and a second, unexpected, methylated product (11) were obtained from 2.
authors.affiliation: School of Chemistry, Tel-Aviv University, Ramat Aviv 69978, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Yosief
authors.forename: A
authors.initials: A
authors.lastname: Rudi
authors.forename: Y
authors.initials: Y
authors.lastname: Kashman
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006571:Heterocyclic Compounds / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013058:Mass Spectrometry; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D006571:Heterocyclic Compounds