New Chromenols From a Southern Australian Tunicate, Aplidium solidum

1996 ◽  
Vol 49 (11) ◽  
pp. 1217 ◽  
Author(s):  
SJ Rochfort ◽  
R Metzger ◽  
L Hobbs ◽  
RJ Capon
Keyword(s):  
Spectroscopic Analysis ◽  
Chemical Degradation ◽  
The Absolute ◽  
Absolute Stereochemistry

Two new chromenols, namely (R)-2-methyl-2-(4-methylpenta-1,3-dienyl)-2H-chromen-6-ol (7) and 1-[(R)-6-hydroxy-2-methyl-2H-chromen-2-yl]-4-methylpentan-2-one (8), have been isolated from a southern Australian tunicate, Aplidium solidum. The structures of (7) and (8) were assigned by spectroscopic analysis, and the absolute stereochemistry of (7) by chemical degradation.

Beyond Polygodial: New Drimane Sesquiterpenes From a Southern Australian Marine Sponge, Dysidea sp.

1993 ◽  
Vol 46 (8) ◽  
pp. 1255 ◽  
Author(s):  
MS Butler ◽  
RJ Capon
Keyword(s):  
Marine Sponge ◽  
Structure Elucidation ◽  
Spectroscopic Analysis ◽  
Marine Metabolites ◽  
Ecological Relationship ◽  
Chemical Correlation ◽  
The Absolute ◽  
First Time ◽  
Absolute Stereochemistry

This report describes the isolation and structure elucidation of four new drimane sesquiterpenes (14)-(17) from a southern Australian marine sponge Dysidea sp. The structures for (14)-(17) were secured by detailed spectroscopic analysis, chemical interconversion and derivatization. Also reported are the known metabolites (+)- euryfuran (7), dihydropallescensin-2 (18), (-)- pallescensin-A (19) and (-)-7-deacetoxyolepupane (6). The rare co-occurrence of two antipodes, (7) and (19), in the same specimen highlights the dangers in assigning absolute stereochemistry based on 'unproven' biosynthetic relationships. The absolute stereochemistry for (6) has been unambiguously established for the first time by chemical interconversion to (7). Furthermore, the absolute stereochemistry of the new marine metabolites listed above, (14)-(17), were determined by chemical correlation to (6). A biosynthetic and ecological relationship is proposed between the metabolites from Dysidea sp. with the known marine and terrestrial antifeedant polygodial (8). Chemical investigations are reported that support this proposition.

The chemical constituents of Australian Flindersia species. XIX. Triterpenoids from the leaves of F. bourjotiana F. Muell

1966 ◽  
Vol 19 (3) ◽  
pp. 455 ◽  
Author(s):  
GJW Breen ◽  
E Ritchie ◽  
WTL Sidwell ◽  
WC Taylor
Keyword(s):  
Chemical Constituents ◽  
Chemical Degradation ◽  
Spectroscopic Methods ◽  
The Absolute ◽  
Absolute Stereochemistry

From the leaves of Flindersia bourjotinna F. Muell. there were isolated sitosterol, triacontanol, lupeol, germanicol, germanicone, and four new triterpenoids, the bourjotinolones A, B, and C, and bourjotone. By chemical degradation and spectroscopic methods, the structures of these substances were shown to be 21,24-epoxy-23,25-dihydroxytirucall-7-en-3one, 23,24-dihydroxytirucalla-7,25-dien- 3-one, 25-chloro-23,24-dihydroxytirucall-7-en-3-one, and 25,26,27-trisnortirucall-7- ene-3,23-dione, respectively. Bourjotinolone C is almost certainly an artefact but bourjotinolone B and bourjotone are less likely to be. From biogenetic and N.M.R. spectral considerations, the absolute stereochemistry of the new triterpenes may be deduced.

Trunculins G - I: New Norsesterterpene Cyclic Peroxides from a Southern Australian Marine Sponge, Latrunculia sp.

1998 ◽  
Vol 51 (7) ◽  
pp. 573 ◽  
Author(s):  
Simon P. B. Ovenden ◽  
Robert J. Capon
Keyword(s):  
Marine Sponge ◽  
Spectroscopic Analysis ◽  
Methyl Esters ◽  
I 11 ◽  
The Absolute ◽  
Cyclic Peroxide ◽  
Absolute Stereochemistry

A Latrunculia sp. collected off Port Phillip Bay, Victoria, returned three new norsesterterpene cyclic peroxides. Trunculins G (9), H (10) and I (11) were isolated as their methyl esters (12), (13) and (14) respectively. Gross structures for these new trunculins were assigned on the basis of spectroscopic analysis, while the absolute stereochemistry about the cyclic peroxide terminus was established by application of the Horeau and Mosher procedures.

Two for One: Structure Revision of the Marine Sesterterpene Tetronic Acid Strobilinin to (8Z,13E,20Z)-Strobilinin and (8E,13Z,20Z)-Strobilinin

1994 ◽  
Vol 47 (5) ◽  
pp. 933 ◽  
Author(s):  
R Davis ◽  
RJ Capon
Keyword(s):  
Natural Product ◽  
Spectroscopic Analysis ◽  
Marine Natural Product ◽  
Geometric Isomers ◽  
Tetronic Acid ◽  
Naturally Occurring ◽  
Structure Revision ◽  
Single Compound ◽  
The Absolute ◽  
Absolute Stereochemistry

A reinvestigation of the known marine natural product strobilinin has revealed it not to be a single compound (2), but to consist of two naturally occurring geometric isomers, neither of which corresponds to the structure originally assigned. These isomers, (8E,13Z,20Z)- strobilinin (10) and (8Z,13E,20Z)-strobilinin (11), were resolved, characterized and identified as their respective acetate derivatives (6) and (7), and their structures assigned by spectroscopic analysis. It would appear that the absolute stereochemistry of the strobilinins is very likely opposite to that of co-occurring variabilin (1).

The structure and partial synthesis of imbricatine, a benzyltetrahydroisoquinoline alkaloid from the starfish Dermasterias imbricata

1991 ◽  
Vol 69 (1) ◽  
pp. 20-27 ◽  
Author(s):  
David L. Burgoyne ◽  
Shichang Miao ◽  
Charles Pathirana ◽  
Raymond J. Andersen ◽  
William A. Ayer ◽  
...  
Keyword(s):  
Key Words ◽  
Absolute Configuration ◽  
Spectroscopic Analysis ◽  
Chemical Degradation ◽  
Model Compounds ◽  
Partial Synthesis ◽  
The Absolute

The structure of imbricatine (1), a cytotoxic metabolite of the starfish Dermasterias imbricata, has been determined by spectroscopic analysis and chemical degradation. Synthesis of model compounds 7 and 18 provided evidence for the absolute configuration and constitution of the benzyltetrahydroisoquinoline substructure of imbricatine. Key words: imbricatine, asteroid, alkaloid.

scholarly journals Kabirimine, a New Cyclic Imine from an Okinawan Dinoflagellate

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 353 ◽  
Author(s):  
Idam Hermawan ◽  
Mikako Higa ◽  
Philipus Uli Basa Hutabarat ◽  
Takeshi Fujiwara ◽  
Kiyotaka Akiyama ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antiviral Activity ◽  
Spectroscopic Analysis ◽  
Computational Study ◽  
Bioactive Molecules ◽  
Chiral Derivatization ◽  
The Absolute ◽  
Syncytial Virus ◽  
Absolute Stereochemistry

On our quest for new bioactive molecules from marine sources, two cyclic imines (1, 2) were isolated from a dinoflagellate extract, inhibiting the growth of the respiratory syncytial virus (RSV). Compound 1 was identified as a known molecule portimine, while 2 was elucidated to be a new cyclic imine, named kabirimine. The absolute stereochemistry of 1 was determined by crystallographic work and chiral derivatization, whereas the structure of 2 was elucidated by means of spectroscopic analysis and computational study on all the possible isomers. Compound 1 showed potent cytotoxicity (CC50 < 0.097 µM) against HEp2 cells, while 2 exhibited moderate antiviral activity against RSV with IC50 = 4.20 µM (95% CI 3.31–5.33).

The Luffarins (A-Z), Novel Terpenes From an Australian Marine Sponge, Luffariella geometrica

1992 ◽  
Vol 45 (10) ◽  
pp. 1705 ◽  
Author(s):  
MS Butler ◽  
RJ Capon
Keyword(s):  
Natural Products ◽  
Marine Sponge ◽  
Coastal Waters ◽  
Marine Natural Products ◽  
Spectroscopic Analysis ◽  
Marine Metabolites ◽  
Chemical Correlation ◽  
The Absolute ◽  
Great Australian Bight ◽  
Absolute Stereochemistry

A marine sponge, Luffariella geometrica Kirkpatrick, collected from the southern Australian coastal waters of the Great Australian Bight, has been found to contain 14 new bicyclic sesterterpenes, luffarin-A (14), -B (15), -C (16), -D (17), -E (18), -F (19), -G (20), -H (21), -I (22), -J (23), -K (24), -L (25), -M (26) and -N (27), a new bicyclic bisnorsesterterpene, luffarin-O (30), a new monocyclic sesterterpene, luffarin-P (32), six new acyclic sesterterpenes, luffarin-Q (35), -R (36), -S (37), -T (38), -U (39) and -V (40), two new diterpenes, luffarin-W (41) and -X (44), and two new bisnorditerpenes luffarin-Y (45) and -Z (46). These novel marine metabolites have been assigned structures, including stereochemistry, on the basis of detailed spectroscopic analysis, chemical correlation, derivatization, and biosynthetic considerations. Studies directed at the absolute stereochemistry of the luffarins have also permitted assignment of absolute stereochemistry to the known marine natural products (E)-neomanoalide (3), (Z)-neomanoalide (4) and dehydroambliol-A (47).

Absolute Stereochemistry of (-)-Wieland-Miescher Ketone as Established by the X-ray Crystallographic and CD Exciton Chirality Methods

1992 ◽  
Vol 57 (7) ◽  
pp. 1459-1465 ◽  
Author(s):  
Nobuyuki Harada ◽  
Tatsuo Sugioka ◽  
Hisashi Uda ◽  
Takeo Kuriki
Keyword(s):  
Structure Analysis ◽  
Absolute Configuration ◽  
X Ray ◽  
The Absolute ◽  
Absolute Stereochemistry

The 8aR absolute stereochemistry of Wieland-Miescher ketone (-)-I was established by the X-ray structure analysis of its bis(4-bromobenzoate) derivatives (1R,6R,8aR)-(+)-IV and (1R,6S,8aR)-(-)-V. The absolute configuration of (-)-I was corroborated further by the application of the CD exciton chirality method to bis(4-bromobenzoates) (+)-IV and (-)-V.

scholarly journals Massiliamide, a cyclic tetrapeptide with potent tyrosinase inhibitory properties from the Gram-negative bacterium Massilia albidiflava DSM 17472T

2020 ◽  
Author(s):  
Andri Frediansyah ◽  
Jan Straetener ◽  
Heike Brötz-Oesterhelt ◽  
Harald Gross
Keyword(s):  
Absolute Configuration ◽  
Inhibitory Activity ◽  
Liquid Culture ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Negative Bacterium ◽  
Gram Negative ◽  
The Absolute ◽  
Potent Inhibitory Activity ◽  
Cyclic Tetrapeptide

AbstractA cyclic tetrapeptide, designated massiliamide, was isolated from the liquid culture of the Gram-negative bacterium Massilia albidiflava DSM 17472T. The structure was elucidated through extensive spectroscopic analysis, including HR-MS and 1D and 2D NMR experiments. The absolute configuration was determined using the Marfey´s method. Massiliamide showed potent inhibitory activity towards tyrosinase with an IC50 value of 1.15 µM and no cytotoxicity.

Determination of the Absolute Stereochemistry of Cyclosmenospongine

2003 ◽  
Vol 66 (9) ◽  
pp. 1263-1265 ◽  
Author(s):  
Natalia K. Utkina ◽  
Vladimir A. Denisenko ◽  
Olga V. Scholokova ◽  
Aleksandra E. Makarchenko
Keyword(s):  
The Absolute ◽  
Absolute Stereochemistry
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