A new aspect of the high-field NMR application of Mosher's method. The absolute configuration of marine triterpene sipholenol A

1991 ◽  
Vol 56 (3) ◽  
pp. 1296-1298 ◽  
Author(s):  
Ikuko Ohtani ◽  
Takenori Kusumi ◽  
Yoel Kashman ◽  
Hiroshi Kakisawa
Keyword(s):  
Absolute Configuration ◽  
High Field ◽  
The Absolute

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.

Microwave assisted glycosylation for determining the absolute configuration of carbohydrates in plant glycosides

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
KP Manfredi ◽  
H Frosch
Keyword(s):  
Absolute Configuration ◽  
Microwave Assisted ◽  
The Absolute

Determination of the absolute configuration of natural products

2014 ◽  
Vol 11 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Ling-Yi KONG ◽  
Peng WANG
Keyword(s):  
Natural Products ◽  
Absolute Configuration ◽  
The Absolute

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,...

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.

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.

Asymmetric Total Synthesis and Determination of the Absolute Configuration of (+)-Srilankenyne via Sequence-Sensitive Halogenations Guided by Conformational Analysis

2021 ◽  
Vol 23 (4) ◽  
pp. 1321-1326
Author(s):  
Hongjun Jang ◽  
Soo Yeon Kwak ◽  
Dongjoo Lee ◽  
Juan V. Alegre-Requena ◽  
Hyoungsu Kim ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Conformational Analysis ◽  
Absolute Configuration ◽  
Asymmetric Total Synthesis ◽  
The Absolute
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