Determination of the absolute configuration of the fragments composing the phytotoxin phomalide

1997 ◽  
Vol 75 (3) ◽  
pp. 314-317 ◽  
Author(s):  
M. Soledade C. Pedras
Keyword(s):  
Absolute Configuration ◽  
Capillary Column ◽  
Acid Methyl Ester ◽  
Isopropyl Ester ◽  
H Nmr ◽  
Acid Methyl ◽  
The Absolute ◽  
Amino Acid Methyl Ester ◽  
Unambiguous Assignment

The absolute configurations of the residues constituting phomalide (1) were determined on the products resulting from acidic hydrolysis. The configurations of the amino acids Val and Leu were determined as (S) and (R), respectively, by chiral GC analysis (Chirasil-Val capillary column), employing N-trifluoroacetyl (TFA) amino acid methyl ester derivatives. The configurations of the hydroxy acids O-Phe and O-Leu were determined as (S) by 1H NMR of the Mosher's esters of the isopropyl ester derivatives. The method described allowed for the unambiguous assignment of the absolute configuration of the α-amino and α-hydroxy acid residues composing phomalide (1). Keywords: absolute configuration, depsipeptide, Mosher's ester.

Determination of the absolute stereochemistry of the fungal metabolite (R)-(−)-2-(4′-hydroxyphenyl)-2-hydroxyethanoic acid (pisolithin B)

1991 ◽  
Vol 69 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Youla S. Tsantrizos ◽  
Kelvin K. Ogilvie
Keyword(s):  
Absolute Configuration ◽  
Lithium Aluminum Hydride ◽  
Optical Rotation ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Fungal Metabolite ◽  
H Nmr ◽  
The Absolute ◽  
Absolute Stereochemistry

The antifungal antibiotic pisolithin B (p-hydroxymandelic acid, 2-(4′-hydroxyphenyl)-2-hydroxyethanoic acid, 1a) was shown to have the absolute (R) configuration. The stereochemistry was established via comparison of its optical rotation to that of its synthetic (R) and (S) enantiomers. The synthetic samples were prepared by the stereospecific reduction of the prochiral α-keto acid, p-hydroxybenzoylformic acid (2-(4′-hydroxyphenyl)-2-oxoethanoic acid, 2a), with (R) or (S)-2,2′-dihydroxy-1,1′-binaphthyl lithium aluminum hydride (BINAL-H). The absolute configuration and enantiomeric purity of both products were determined using the 1H NMR of their isobutyl esters in the presence of the chiral solvating agent (R)-(−)-2,2,2-trifluoro-1-(9-anthryl)ethanol. Key words: pisolithin B, p-hydroxymandelic acid, antifungal, absolute configuration.

1H—NMR-spektroskopische Bestimmung der diastereomeren Reinheit und der absoluten Konfiguration am Phosphoratom von tButyl-phenyl-phosphinsäure-(—)-menthylester / Determination of the Diastereomeric Purity and the Absolute Configuration at Phosphorus of tButyl-phenyl-phosphinic Acid (—)-Menthyl Ester by Means of 1H NMR Spectroscopy

1977 ◽  
Vol 32 (5) ◽  
pp. 589-593 ◽  
Author(s):  
Reiner Luckenbach ◽  
Hans-H. Bechtolsheimer
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Absolute Configuration ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Phosphinic Acid ◽  
H Nmr ◽  
The Absolute ◽  
Diastereomeric Purity

The preparation and separation into diastereomers of tbutyl-phenyl-phosphinic acid (—)-menthyl ester (1a) is reported. The diastereomeric purity as well as the absolute configuration at phosphorus of 1 a can be deduced from the detailed analysis of the 1H NMR spectra of samples of 1a differing in their diastereomer ratios.

F-THENA: a chiral derivatizing agent for the determination of the absolute configuration of secondary aromatic alcohols with a self-validating system

2016 ◽  
Vol 14 (46) ◽  
pp. 11002-11012 ◽  
Author(s):  
Kulvadee Dolsophon ◽  
Jakapun Soponpong ◽  
Jittra Kornsakulkarn ◽  
Chawanee Thongpanchang ◽  
Samran Prabpai ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
H Nmr ◽  
System P ◽  
Aromatic Alcohols ◽  
Derivatizing Agent ◽  
Chiral Derivatizing Agent ◽  
The Absolute

F-THENA can be used with 19F- and 1H-NMR to assign the configuration of 2° aromatic alcohols with a self-validation system.

scholarly journals Determination of Absolute Stereochemistry of Natural Alicyclic Glycosides by 1H NMR Spectroscopy without Application of Chiral Reagents – An Indication

2011 ◽  
Vol 6 (5) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Tatyana N. Makarieva ◽  
Larisa K. Shubina ◽  
Alla G. Guzii ◽  
Natalya V. Ivanchina ◽  
Vladimir A. Denisenko ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Absolute Configuration ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
H Nmr ◽  
Steroid Glycosides ◽  
The Absolute ◽  
Absolute Stereochemistry

A study has been made of the 1H NMR spectra of peracetylated β-glucopyranosides and α-arabinopyranosides obtained by reaction of D- and L-glucoses, and L- and D-arabinoses with either ( R)- or ( S)-2-octanols. The obtained and literature data show that 1H NMR spectra may be used to determine the absolute configuration of the aglycone moieties of some alicyclic glycosides without the need to synthesize derivatives with chiral reagents, as long as the absolute configuration of their monosaccharide moiety is known or vice versa. Spectra of marine steroid glycosides and their acetates containing glycosylated side chains as alicyclic fragments were also examined. It was shown that analysis of 1H NMR spectra for the determination of the absolute configuration is more applicable in the cases when glycosides have the same substitution in the D-ring of the aglycone moiety.

Synthesis and Application of Methyl Itaconate‒Anthracene Adducts in Configuration Assignment of Chiral Secondary Alcohols by 1H NMR

2021 ◽  
Author(s):  
Puracheth Rithchumpon ◽  
Neeranuth Intakaew ◽  
Nopawit Khamto ◽  
Saranphong Yimklan ◽  
Piyarat Nimmanpipug ◽  
...  
Keyword(s):  
1H Nmr ◽  
Absolute Configuration ◽  
Secondary Alcohols ◽  
The Novel ◽  
H Nmr ◽  
Configuration Assignment ◽  
The Absolute

The novel chiral derivatising agents (CDAs) as methyl itaconate‒anthracene adducts (MIAs) were reported for the absolute configuration determination of chiral secondary alcohols by 1H NMR technique. These adducts were facilely...

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.

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