Lepadins F-H. New cis-Decahydroquinoline Alkaloids from the Australian Ascidian, Aplidium tabascum
Abstract
Chemical investigation of a Great Barrier Reef ascidian, Aplidium tabascum, has resulted in the isolation of three new cis-decahydroquinoline alkaloids, lepadins F-H (4-6). The three new compounds differ from the previously isolated lepadins A-C (1-3) in that they contain a fully saturated 5-hydroxyoctyl side chain attached at C-5, an unsaturated eight-carbon ester moiety attached to C-3, and opposite stereochemistry at C-5 and C-3. Lepadins G (5) and H (6) are epimers at C-2. NMR and molecular modeling studies indicated that the three new compounds adopt a chair-chair conformation in which the nitrogen equatorially substitutes ...
View more >Chemical investigation of a Great Barrier Reef ascidian, Aplidium tabascum, has resulted in the isolation of three new cis-decahydroquinoline alkaloids, lepadins F-H (4-6). The three new compounds differ from the previously isolated lepadins A-C (1-3) in that they contain a fully saturated 5-hydroxyoctyl side chain attached at C-5, an unsaturated eight-carbon ester moiety attached to C-3, and opposite stereochemistry at C-5 and C-3. Lepadins G (5) and H (6) are epimers at C-2. NMR and molecular modeling studies indicated that the three new compounds adopt a chair-chair conformation in which the nitrogen equatorially substitutes the cyclohexyl ring. This contrasts with lepadins A-C (1-3), which adopt a chair-chair conformation in which the nitrogen axially substitutes the cyclohexyl ring.
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View more >Chemical investigation of a Great Barrier Reef ascidian, Aplidium tabascum, has resulted in the isolation of three new cis-decahydroquinoline alkaloids, lepadins F-H (4-6). The three new compounds differ from the previously isolated lepadins A-C (1-3) in that they contain a fully saturated 5-hydroxyoctyl side chain attached at C-5, an unsaturated eight-carbon ester moiety attached to C-3, and opposite stereochemistry at C-5 and C-3. Lepadins G (5) and H (6) are epimers at C-2. NMR and molecular modeling studies indicated that the three new compounds adopt a chair-chair conformation in which the nitrogen equatorially substitutes the cyclohexyl ring. This contrasts with lepadins A-C (1-3), which adopt a chair-chair conformation in which the nitrogen axially substitutes the cyclohexyl ring.
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Journal Title
Journal of Natural Products
Volume
65
Publisher URI
Copyright Statement
© 2002 American Chemical Society. Self-archiving of the author-manuscript version is not yet supported by this publisher. The contents of this journal can be freely accessed online via the ACS web page. Use hypertext link above to access the ACS website.
Subject
Chemical sciences
Biological sciences
Biomedical and clinical sciences
Traditional, complementary and integrative medicine