Difference CD spectrum : the absolute configuration of methyl sarcophytoate

1991 ◽  
Vol 32 (45) ◽  
pp. 6595-6596 ◽  
Author(s):  
Midori O. Ishitsuka ◽  
Takenori Kusumi ◽  
Hiroshi Kakisawa
Keyword(s):  
Absolute Configuration ◽  
Cd Spectrum ◽  
The Absolute

scholarly journals Struthiolanone: A Flavanone-Resveratrol Adduct from Struthiola Argentea

2008 ◽  
Vol 3 (2) ◽  
pp. 1934578X0800300
Author(s):  
Sloan Ayers ◽  
Deborah L. Zink ◽  
Robert Brand ◽  
Seef Pretorius ◽  
Dennis Stevenson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Absolute Configuration ◽  
High Resolution Mass Spectrometry ◽  
2D Nmr ◽  
Spectroscopic Techniques ◽  
Cd Spectrum ◽  
High Resolution Mass ◽  
The Absolute ◽  
Resolution Mass

Struthiolanone (1), a flavanone-resveratrol adduct, was isolated from Struthiola argentea. Its structure was determined by high-resolution mass spectrometry and 1D- and 2D-NMR spectroscopic techniques. The absolute configuration was determined by comparison of the CD spectrum of biflavonoids. This compound appears to be the first example of a flavanoid-stilbene adduct.

scholarly journals Alkaloids from the Tuber of Stephania cf. rotunda

2016 ◽  
Vol 11 (7) ◽  
pp. 1934578X1601100
Author(s):  
Duy Hoang Le ◽  
Katsumi Nishimura ◽  
Takao Tanahashi
Keyword(s):  
Absolute Configuration ◽  
Chemical Investigation ◽  
Chemical Methods ◽  
H Nmr ◽  
Chemical Structures ◽  
Cd Spectrum ◽  
Nmr Data ◽  
The Absolute ◽  
First Time

Chemical investigation of the tuber of Stephania cf. rotunda collected in Vietnam led to the isolation of a new stephaoxocane-type alkaloid, stepharotudine (1), twenty-eight known alkaloids, and two known amides. The chemical structures of the isolated compounds were determined by spectroscopic and chemical methods. The absolute configuration of the new compound was determined from its CD spectrum and by 1H NMR analyses of its MPA esters. For the known alkaloids (-)-crebanine-β- N-oxide (2), uthongine (3), and palmatrubine (4), fully assigned NMR data are also reported for the first time.

Evaluation of Different Synthetic Routes to (2R,3R)-3-Hydroxymethyl-2-(4-hydroxy- 3-methoxyphenyl)-1,4-Benzodioxane-6-Carbaldehyde

2020 ◽  
Vol 23 (26) ◽  
pp. 2960-2968
Author(s):  
Renáta Kertiné Ferenczi ◽  
Tünde-Zita Illyés ◽  
Sándor Balázs Király ◽  
Gyula Hoffka ◽  
László Szilágyi ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Stereoselective Synthesis ◽  
Cotton Effect ◽  
Enantioselective Synthesis ◽  
Aryl Group ◽  
Target Molecule ◽  
Synthetic Routes ◽  
The Absolute

The reported enantioselective synthesis for the preparation of (+)-(2R,3R)-2-(4- hydroxy-3-methoxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-carbaldehyde, precursor for the stereoselective synthesis of bioactive flavanolignans, could not be reproduced. Thus, the target molecule was prepared via the synthesis and separation of diastereomeric O-glucosides. TDDFT-ECD calculations and the 1,4-benzodioxane helicity rule were utilized to determine the absolute configuration. ECD calculations also confirmed that the 1Lb Cotton effect is governed by the helicity of the heteroring, while the higher-energy ECD transitions reflect mainly the orientation of the equatorial C-2 aryl group.

Absolute configuration at C(20) of the derivatives of 21-nor-5α-cholane-20,24-diol

1980 ◽  
Vol 45 (9) ◽  
pp. 2443-2451
Author(s):  
Vladimír Pouzar ◽  
Miroslav Havel
Keyword(s):  
Absolute Configuration ◽  
Side Chain ◽  
Chemical Correlation ◽  
The Absolute ◽  
Derivatives Of

Derivatives of 21-nor-5α-cholane-20,24-diol XI and XIX were prepared by stepwise construction of the side-chain in the position 17β. Their absolute configuration at C(20) was determined on the basis of chemical correlation with the derivatives of 21-nor-5α-cholan-20-ol, XVI and XXIV. The absolute configuration of alcohols XVI and XXIV was determined from the ratio of the yields in which they are formed during the reduction of ketone X and using the benzoate rule. To compounds XI-XVIII the configuration 20R and to compounds XIX-XXVI the configuration 20S has been assigned.

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 Rapid Organocatalytic Chirality Analysis of Amines, Amino Acids, Alcohols, Amino Alcohols and Diols with Achiral Iso(thio)cyanate Probes

2021 ◽  
Author(s):  
Eryn Nelson ◽  
Jeffrey S. S. K. Formen ◽  
Christian Wolf
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Rapid Determination ◽  
Amino Alcohols ◽  
Enantioselective Synthesis ◽  
Widespread Occurrence ◽  
Chiral Compounds ◽  
New Methods ◽  
The Absolute

The widespread occurrence and significance of chiral compounds does not only require new methods for their enantioselective synthesis but also efficient tools that allow rapid determination of the absolute configuration,...

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