Studies of Australian Soft Corals. XLVII. New Halogenated Briaran Diterpenes From a Briareum Species (Octocorallia, Gorgonacea)

1989 ◽  
Vol 42 (10) ◽  
pp. 1727 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
IM Vasilescu ◽  
PN Alderslade
Keyword(s):  
High Field ◽  
Soft Corals ◽  
Difference Spectroscopy ◽  
New Metabolites

Two new halogenated briaran diterpenes (3) and (4) are reported from a Briareumspecies of soft corals from waters off Darwin, N.T. Their structures were determined by high-field n.m.r. spectroscopy including 2-D 13C-1 H-correlation experiments and COSY-45 experiments, and stereochemical features were delineated by n.0.e. difference spectroscopy. The new metabolites are (1R*,2S*,4S*,6S*,7R',8R*,9S*,10S*,11Z,14S*,17S*)-14-acetoxy-6-chloro-4,8-epoxy-9,17-dihydroxy-2-propiony10xybriar5(16,11-dien-18-one (3) and (1R*,2R*,3S*,6S*,7R*,8R*,9S*,10S*,11R*,13Z)-3,9-diacetoxy-6-chloro-8-hydroxy-2-propionyloxybriara-5(16),13-diene-12,18-dione (4). The isolation of briaran diterpenes from this specimen supports its inclusion in the genus Briareum.

Studies of Australian Soft Corals. XLII. Structure Determination of New Briaran Derivatives From Briareum steckei (Coelenterata, Octocorallia, Gorgonacea)

1987 ◽  
Vol 40 (12) ◽  
pp. 2085 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
W Patalinghug ◽  
BW Skelton ◽  
I Vasilescu ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Field ◽  
Soft Corals ◽  
X Ray ◽  
Relative Stereochemistry ◽  
Minor Metabolite ◽  
A Minor ◽  
New Compounds ◽  
New Metabolites

The structure and relative stereochemistry of four new metabolites from Briareum steckei has been deduced from 2D-n.m.r. experiments at high field, and confirmed by a single-crystal X-ray determination of a minor metabolite. The new compounds are non-halogenated briaran derivatives: (1R*,2S*,3R*,5Z,7S*,8(17)Z,l0R*, llR *,12S*,14S*)- 3,14-diacetoxy- 11,12-epoxy- 18-oxobriara-5,8(17)-dien-2-yl butanoate (3), its 3-deacetoxy derivative (4), (1R*,2R*,4R*,5Z,7S*,8(17)Z,10R*, 11R *,12S*,14S*)-4,14-diacetoxy-11,12-epoxy-18-oxobriara-5,8(17)-dien-2-yl butanoate (5) and the related 2-propanoate (6). Single-crystal X-ray determinations were performed on (5) and (6).

scholarly journals Trichilones A–E: New Limonoids from Trichilia adolfi

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3070
Author(s):  
Mariela Gonzalez-Ramirez ◽  
Ivan Limachi ◽  
Sophie Manner ◽  
Juan C. Ticona ◽  
Efrain Salamanca ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
High Field ◽  
Chemical Constituents ◽  
Ethanol Extract ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Murine Macrophage ◽  
New Metabolites

In addition to the trichilianones A–D recently reported from Trichilia adolfi, a continuing investigation of the chemical constituents of the ethanol extract of the bark of this medicinal plant yielded the five new limonoids 1–5. They are characterized by having four fused rings and are new examples of prieurianin-type limonoids, having a ε-lactone which in 4 and 5 is α, β- unsaturated. The structures of the isolated metabolites were determined by high field NMR spectroscopy and HR mass spectrometry. The new metabolites were shown to have the ε-lactone fused with a tetrahydrofuran ring which is connected to an oxidized hexane ring joined with a cyclo-pentanone having a 3-furanyl substituent. As the crude extract possesses antileishmanial activity, the compounds were assayed for cytotoxic and antiparasitic activities in vitro in murine macrophage cells (raw 264.7 cells) and in Leishmania amazoniensis as well as L. braziliensis promastigotes. Metabolites 1–3 and 5 showed moderate cytotoxicity (between 30–94 µg/mL) but are not responsible for the antileishmanial effect of the extract.

Tropical Marine-Algae. VI. New Monoterpenes From Several Collections of Chondrococcus hornemannii (Rhodophyta, Gigartinales, Rizophyllidaceae)

1989 ◽  
Vol 42 (11) ◽  
pp. 1983 ◽  
Author(s):  
JC Coll ◽  
AD Wright
Keyword(s):  
Red Algae ◽  
Positional Isomer ◽  
High Field ◽  
Marine Algae ◽  
Circumstantial Evidence ◽  
New Metabolites

Four collections of the red algae Chondrococcus hornemannii( Lyngbye ) Schmitz afforded a range of monoterpenes. Structures of ten new metabolites were elucidated by using high- field n.m.r. spectroscopy techniques including 2.D proton-carbon correlation experiments. The new monoterpenes were: (Z)-3-bromo-8-chloro-6-chloromethyl-2-methylocta-1,6-diene (9,6-hydroxymethyl-2-methylocta-2,8-dien-6-ol (6), (Z)-6-hydroxymethyl-2-methylocta-1,6-diene- 3,8-diol (7), (2)-6-hydroxymethyl-2-methyIocta-2,6-dien-8-ol (8), (2)-8-chloro-6-chloromethyl-3- methoxyocta-1,6-diene (9), (Z)-8-chloso-6-chloromethyl-2-methylocta-l,6-dien-3-ol (10), (2E,62) 8-chloro-6-chloromethyl-1-methoxy-2-methylocta-2,6-diene (11), (2E,6Z)-8-chloro-6-chloromethyl- 2-methylocta-2,6-dien-1-ol (12), (Z)-6-chloromethyl-3,8-dimethoxy-2-methylocta-1,6-diene (13) and its positional isomer (Z)-6-chloromethyl-1,8-dimethoxy-2-methyoca-26-diene (14). Although it is possible that some of the metabolites listed may be artefacts of extraction, circumstantial evidence is offered which suggests that most isolates were present in the plant prior to extraction.

Studies of Australian soft corals. XXXII. The structure determination of degraded xenicin-type diterpenes from several Efflatounaria species

1983 ◽  
Vol 36 (11) ◽  
pp. 2279 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
VA Patrick ◽  
DM Tapiolas
Keyword(s):  
Single Crystal ◽  
Chemical Transformation ◽  
Structure Determination ◽  
High Field ◽  
Soft Corals ◽  
X Ray ◽  
The Third

Three new diterpenes have been isolated from soft corals of the genus Efflatounaria (Coelenterata, Octocorallia, Alcyonacea, Xeniidae). The structure of the first compound (4) was elucidated on the basis of high-field 1H n.m.r. spectroscopy while that of the second metabolite (5) was determined by single-crystal X-ray analysis. The third diterpene (6) was structurally related to (5), and its structure was confirmed by chemical transformation. All three diterpenes can be derived from xenicin-type precursors, by cleavage and recyclization.

Studies of Australian Soft Corals. XLVIII. New Briaran Diterpenoids From the Gorgonian Coral Junceela gemmacea

1990 ◽  
Vol 43 (1) ◽  
pp. 151 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
GM Konig
Keyword(s):  
High Field ◽  
Two Dimensional ◽  
Soft Corals ◽  
Gorgonian Coral

The structures of three new briaran based diterpenes are reported from the gorgonian coral Junceela gemmacea. Their structures were deduced on the basis of extensive one- and two-dimensional high-field n.m.r. experiments. The metabolites were (1R,2R,5Z,7R,8S,9R,10R,11R,14R,17S)-2,14-diacetoxy-8,17:11,20-bisepoxy-9-hydroxybriar-5-en-18-one (3), (1R,2R,5Z,7R,8S,9R,10R,11Z,14R,17S)-2,14-diacetoxy-8,17-epoxy-9-hydroxybriara-5,11-dien-18-one (4), and 1R,2R,5Z,7R,8S,9R,10R,12R,14R,17S)-2,14-diacetoxy-8,17-epoxy- 9,12-dihydroxybriara-5,11(20)-dien-18-one (5). The compounds are closely related to recently reported metabolites from Briareum species of soft corals.

Studies of Australian Soft Corals. XLIII. The Structure Elucidation of a New Diterpene From Alcyonium molle

1989 ◽  
Vol 42 (5) ◽  
pp. 665 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
MC Dai
Keyword(s):  
Absolute Configuration ◽  
High Field ◽  
Structure Elucidation ◽  
Kinetic Resolution ◽  
Soft Coral ◽  
Soft Corals ◽  
Resolution Method ◽  
The Absolute ◽  
First Time

The isolation of a new cladiellin based diterpene (6), (1S,2R,3S,4R,SR,6S,8E,11S,12R,13S,14S)-3-acetoxy-2,12-dibutanoyloxycladiell-8-ene-4,11-diol is reported from the soft coral Alcyonium molle (Octocorallia, Alcyonacea, Alcyoniidae). The structure was deduced by high-field n.m.r. spectroscopy including 13C-lH shift correlated 2D n.m.r. experiments and n.O.e. measurements. The absolute configuration was based on the kinetic resolution method of Horeau. This highly derivatized diterpene (6) is the first alcyonacean derived metabolite to possess hydroxy functionalities protected as butyrate esters, although this feature is relatively common among gorgonacean metabolites. Gorgosterol (7), which cooccurs with (6) in A. molle was identified and its 13C n.m.r. spectrum reported for the first time.

Studies of Australian Soft Corals. XXXIX. New Sesquiterpene Metabolites From Several Xenia Species (Xeniidae, Octocorallia, Anthozoa)

1986 ◽  
Vol 39 (10) ◽  
pp. 1717 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
RH Willis
Keyword(s):  
Natural Products ◽  
Spectroscopic Study ◽  
Soft Corals ◽  
Chemical Correlation ◽  
Absolute Stereochemistry ◽  
New Metabolites

The structures and absolute stereochemistry of three new metabolites isolated from Xenia species of soft corals have been determined by spectroscopic study and chemical correlation with known natural products. The new metabolites are: (1S,2R,4R,4aS,5Z,8aR)-1,2-epoxy-4-isopropyl-1,6-dimethyl-1,2,3,4,4a,7,8,8a-octahydronaphthalene (4), (1E,4R,4aR,5S,6R,8aR)-5,6-epoxy-4-isopropyl-6-methyl- 3,4,4a,5,6,7,8,8a-octahydronaphthalene-1-methanol acetate (5) and (1E,5Z,4R,4aR,8aR)-4-isopropyl-6-methyl-3,4,4a,7,8,8a- hexahydronaphthalene-1-methanol (6).

Studies of Australian Soft Corals. XLVI. New Diterpenes From a Briareum Species (Anthozoa, Octocorallia, Gorgonacea)

1989 ◽  
Vol 42 (10) ◽  
pp. 1705 ◽  
Author(s):  
BF Bowden ◽  
JC Coll ◽  
IM Vasilescu
Keyword(s):  
High Field ◽  
Nuclear Overhauser Effect ◽  
Soft Corals ◽  
Overhauser Effect ◽  
Relative Stereochemistry ◽  
Nuclear Overhauser ◽  
New Compounds

The structures and relative stereochemistry of nine new briaran -based diterpenes from a Briareum species have been deduced from 2-D n.m.r. experiments at high field, and nuclear Overhauser effect experiments. The new compounds are (1R*2R*,3R*,5Z,7S*,8S*,9S*,10S*,11R*,-12S*,14S*,17R*)-2,3,14-triacetoxy-8,17:11,12-bisepoxy-9-hydroxybriar-5-en-18-one (5), (1R* ,2R* ,3R* ,5Z*,7S*,8S* ,9S*,10S*,11R*,12S*, 14S*, 17R*)-3,14-diacetoxy-2-butyryloxy-8,17:11,12-bisepoxy-9-hydroxybriar-5-en-18-one (6),(1R*,2R*,3R*,5Z,7S*,8S*,9S*,10S*,11R*,12S*,14S)-2,3,14-triacetoxy-11,12-epoxybriara-5,8(17)-dien-18-one(17),(1S*,2S*,4R*,5Z,7S*,8S*,9S*,10S*,2,4,9.12-tetraacetoxy-8,17-epoxy-11-hydroxybriara-5,13-dien-18-one (8),(1S*, 2S*,4R*, 5Z,7S*,8S*,9S*,10S*, 11S*, 12R*,13Z,17R*)-2,4,9-triacetoxy-8,17-epoxy-11,12-dihydroxybriara-5,13-dien-18-one (9), (1S *,2S*,4R*,5Z,7S*,8S*,9S*,10S*, 11S *,12R*,13Z,17R*)-2,4,9,12-tetraacetoxy-8,17-epoxy-11-hydroxybriara-5,13-dien-18-one(10),(1Si,2S*,5Z,7S',8S*,-9S*,10S*,11R*,12R*,13Z,17R*)-2,12-diacetoxy-8,17-epoxy-9-hydroxybriara-5,13-dien-18-one(ll), (1R*,2R*,3Si,5Z,7S* ,8S* ,9S* ,10S* ,11Z,14S*,17R*)-2,14-diacetoxy-3-butyryloxy-8,17-epoxy-9-hydroxybriara-5,11-dien-18-one (12) and (1R *,2R*,3S*,5Z,7S*,8S*,9S*,10S*,11Z,-14S',17R*)-2,3,14-triacetoxy-8,17-epoxy-9-hydroxybriara-5,11-dien-18-one (13). In addition to the nine new briaran derivatives, the same coral afforded two cladiellane derivatives (1R*,4R*,5S*,6R*,8R*,12R*,13R*,14R*)-cladiellane-4,8,12-triol (14) and its 4-acetoxy derivative (15). Aknowncembranoid diterpene (1R *,4R*,ZE,7E,l1E)-cembra-2,7,11-trien-4-ol(21) wasalso isolated together with an unprecedented perhydrophenanthrene-based diterpene (20): (1R *, 1aR*,4S*,4aR*,5aR*,8aR*)-4-isopropyl-l,8a-dimethyl-5-methylenetetradecahydrophenanthren-1-ol. The extraordinary biosynthetic ability of soft corals from the genus Briareum is once more revealed.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

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