| Abstract
| - Three pairs of nitrogen-containing metabolites, asmarines A−F (1−6), were isolated from the Red Seasponge Raspailia sp., collected in the Dahlak Archipelago, Eritrea. Although the first pair could fully beseparated to give compounds 1 and 2, the other two pairs could only be enriched up to about 80% of oneisomer. The structures of the new compounds were established by spectroscopic means. Besides theasmarines, 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 mainlythe Cotton effect of the dicarbonyl derivative (9) of chelodane (8). A O,N(7‘)-dimethyl derivative (10) anda second, unexpected, methylated product (11) were obtained from 2.
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