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.

HIGH FIELD PHASE DIAGRAM OF THE FIELD-INDUCED SUPERCONDUCTING STATE OF λ-(BETS)2FeCl4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3101-3104
Author(s):  
L. BALICAS ◽  
J. S. BROOKS ◽  
K. STORR ◽  
S. UJI ◽  
M. TOKUMOTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Superconducting State ◽  
Ground State ◽  
Electrical Transport ◽  
High Field ◽  
Two Dimensional ◽  
Exchange Field ◽  
Organic Conductor ◽  
Field Phase ◽  
Antiferromagnetic Ground State

We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor λ- (BETS) 2 FeCl 4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T, and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe 3+ ions. We further argue that the Fe 3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state. Here we provide experimental evidence indicating that this state, as well as the insulating antiferromagnetic ground state, is extremely sensitive to hydrostatic pressure.

scholarly journals Searching for a UV-filter in the eyes of high flying birds

2018 ◽  
Author(s):  
Malgorzata Zawadzka ◽  
Beatrix Ràcz ◽  
Dario Ambrosini ◽  
Carl Henrik Gørbitz ◽  
Jens Preben Morth ◽  
...  
Keyword(s):  
Aqueous Humor ◽  
High Field ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
High Altitudes ◽  
Chromatographic Purification ◽  
Uv Filter ◽  
Nmr Methods

AbstractAn ultraviolet (UV)-absorbing compound of unknown identity is present in the aqueous humor of geese and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as “compound X”, was fractionated and examined using a variety of spectroscopic techniques including LC-MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective “compound X”. It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.

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.

High field De Haas-van Alphen studies in the charge density wave state of the quasi two-dimensional monophosphate tungsten bronze P4W12O44

1997 ◽  
Vol 86 (1-3) ◽  
pp. 2133-2134 ◽  
Author(s):  
C. Le Touze ◽  
L.H. Nguyen ◽  
C. Schlenker ◽  
E. Steep ◽  
M. Greenblatt
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
High Field ◽  
Density Wave ◽  
Tungsten Bronze ◽  
Two Dimensional ◽  
Wave State

Control of Two-Dimensional High Field Domain in Gunn Effect Functional Devices

1974 ◽  
Author(s):  
T. Nakamura ◽  
S. Hasuo ◽  
G. Goto ◽  
K. Kazetani ◽  
H. Ishiwari ◽  
...  
Keyword(s):  
High Field ◽  
Two Dimensional ◽  
Gunn Effect

scholarly journals Fast low-specific absorption rate B0 -mapping along projections at high field using two-dimensional radiofrequency pulses

2014 ◽  
Vol 73 (3) ◽  
pp. 901-908 ◽  
Author(s):  
Olivier Reynaud ◽  
Daniel Gallichan ◽  
Benoit Schaller ◽  
Rolf Gruetter
Keyword(s):  
High Field ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Two Dimensional ◽  
Specific Absorption

Fe(CO)3 and Rh(acac) complexes of ergosteryl and 7-dehydrocholesteryl acetates: A high field nuclear magnetic resonance study

1988 ◽  
Vol 66 (12) ◽  
pp. 3003-3011 ◽  
Author(s):  
Richard E. Perkier ◽  
Michael J. Mcglinchey
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Field ◽  
Chemical Shifts ◽  
Nuclear Magnetic Resonance Study ◽  
Two Dimensional ◽  
Magnetic Resonance Study ◽  
Anisotropic Properties ◽  
Diene System ◽  
Nmr Techniques

The 500 MHz 1H and 125 MHz 13C spectra of ergosteryl and 7-dehydrocholesteryl acetate were recorded in C6D6 and CDCl3 and assigned using two-dimensional NMR techniques. It is shown that incorporation of an Fe(CO)3 or a Rh(acac) moiety onto the ring B diene system affects the chemical shifts of neighbouring protons and carbons. These changes are discussed in terms of the anisotropic properties of the organometallic fragments.

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