Novel Bromo Metabolites From a Dictyoceratid Sponge of the Cacospongia Genus

1989 ◽  
Vol 42 (5) ◽  
pp. 611 ◽  
Author(s):  
MJ Garson ◽  
DC Manker ◽  
KE Maxwell ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Structure Analysis ◽  
Absolute Configuration ◽  
Marine Sponge ◽  
Carbon Skeleton ◽  
Crystallographic Structure ◽  
X Ray ◽  
The Absolute ◽  
New Compounds

Two novel brominated metabolites, tribromocacoxanthene (3) and tetrabromocacoxanthene (4),have been isolated from a marine sponge of the Cacospongia genus (family Thorectidae ) along with 12-epideoxoscalarin (2). The structures of compounds (3), systematic name (2S,4aS,9aS)-2,7-dibromo-4a-bromomethyl-1,1-dimethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthene, and (4), systematic name (2S,4aS,9aS)-2,5,7-tribromo-4a-bromomethyl-l,1-dimethyl-2,3,4,4a,9,9a-hexahydro-1H-xanthene , were deduced from analysis of 1H and 13C n.m.r. data and that of (3) was confirmed by X-ray crystallographic structure analysis which provided the absolute configuration. The two new compounds are the first tricyclic examples of a carbon skeleton previously isolated only from algae. The chemotaxonomic implication of the isolation of these new compounds is discussed.

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 Preparative-scale HPLC Resolution of Metallacyclic η3-Allyltricarbonyliron Complexes and Determination of the Absolute Configuration by X-Ray Crystal Structure Analysis

1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner
Keyword(s):  
Crystal Structure ◽  
Silica Gel ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
Preparative Scale ◽  
X Ray ◽  
The Absolute

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.

Die absolute Konfiguration der Juglomycine/The Absolute Configuration of the Juglomycins

1989 ◽  
Vol 44 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Johann Krupa ◽  
Helmut Lackner ◽  
Peter G. Jones ◽  
Karen Schmidt-Bäse ◽  
George M. Sheldrick
Keyword(s):  
Single Crystal ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
X Ray ◽  
The Absolute ◽  
Dibromo Derivative

The absolute configurations of the known juglomycins A (1) and B (2) have been elucidated by single crystal X-ray structure analysis of 1 and its 6,8-dibromo derivative (1b). The structure of 2 has been corrected; it differs from 1 in its configuration at C-4', and not at C-3' as previously assumed. Relationships with the closely related isochromanquinone antibiotics are discussed.

Röntgenstrukturanalyse von Mezerein aus Daphne mezereum L. / X-Ray Structure Analysis of Mezerein from Daphne mezereum L

1977 ◽  
Vol 32 (9-10) ◽  
pp. 678-682 ◽  
Author(s):  
H. Lotter ◽  
A. Jones ◽  
M. Sturm
Keyword(s):  
Structure Analysis ◽  
Absolute Configuration ◽  
Direct Methods ◽  
Antileukemic Activity ◽  
Methods Comparison ◽  
X Ray ◽  
The Absolute

Abstract Mezerein, Daphne mezereum, X-Ray Structure, Antileukemic Principle The X-ray structure of Mezerein from Daphne mezereum L. was determined by aid of direct methods. Comparison with Phorbol and Daphnetoxin led to the absolute configuration. A tentative mechanism for the antileukemic activity is proposed.

Die Röntgenstrukturanalyse von 2-(m-Brombenzyl-4.7.8.9- tetra-O-acetyl-N-acetyl-α -ᴅ-neuraminsäure * / X-Ray-Structure-Analysis of 2-(m-Br-benzyl) -4,7,8,9-tetra-O-acetyl-N-acetyl- α-ᴅ-neuraminic Acid

1974 ◽  
Vol 29 (7-8) ◽  
pp. 317-322 ◽  
Author(s):  
H Wawra
Keyword(s):  
Structure Analysis ◽  
Absolute Configuration ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Biochemical Properties ◽  
Neuraminic Acid ◽  
X Ray ◽  
The Absolute

Abstract The structure of 2-(m-Br-benzyl) -4,7,8,9-tetra-O-acetyl-N-acetyl-α-ᴅ-neuramine acid was solved by heavy-atom methods using three-dimensional X-ray data. Known biochemical properties of the molecule allow to determine the absolute configuration.

A New Series of Diterpenes from Australian Spongia Species

1979 ◽  
Vol 32 (4) ◽  
pp. 867 ◽  
Author(s):  
R Kazlauskas ◽  
PT Murphy ◽  
RJ Wells ◽  
K Noack ◽  
WE Oberhansli ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Single Crystal ◽  
Absolute Configuration ◽  
Spectral Methods ◽  
Barrier Reef ◽  
X Ray ◽  
The Absolute ◽  
New Compounds ◽  
The Relationship ◽  
Circular Dichroïsm

Great Barrier Reef sponges of the genus Spongia have yielded eight closely related tetracyclic furanoditerpenes. The structures, assigned on the basis of spectral methods, have been confirmed by a single-crystal X-ray analysis of one of the metabolites and the relative stereochemical features have been defined. The absolute configuration of this metabolite was determined by circular dichroism, which allowed the relationship between the eight new compounds to be determined.

Alkaloids of Rauvolfia salicifolia GRISEB species

1982 ◽  
Vol 47 (11) ◽  
pp. 2912-2921 ◽  
Author(s):  
Patricia Sierra ◽  
Ladislav Novotný ◽  
Zdeněk Samek ◽  
Miloš Buděšínský ◽  
Ladislav Dolejš ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Cd Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute

From the endemic Cuban species Rauvolfia salicifolia GRISEB nine alkaloids were isolated of which the following seven had been already described: (+)-ajmalidine (I), (-)-reserpiline (II), (-)-isoreserpiline (III), (-)-isocarapanaubine (IV), (-)-ajmalicine (V), (+)-vellosimine (VI), and (+)-yohimbine (VII). The structure of (-)-raucubaine (VIII) had been previously determined by X-ray diffraction and the structure of the alkaloid (-)-raucubainine (IX) was suggested on the basis of its conversion to (-)-raucubaine (VIII). The absolute configuration of (-)-raucubaine and (-)-raucubainine was elucidated by CD spectroscopy.

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