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.

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 of β-amino-α-ferrocenyl alcohols

2005 ◽  
Vol 2005 (11) ◽  
pp. 712-715 ◽  
Author(s):  
Hai-Ying Zhao ◽  
Zhan-Xi Bian ◽  
Bao-Guo Li
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Chain Structure ◽  
Lithium Aluminum ◽  
Polymeric Chain ◽  
X Ray ◽  
H Nmr ◽  
Hydrogen Bonding Interactions ◽  
Trimethylsilyl Ethers ◽  
New Compounds

β-Amino-α-ferrocenyl alcohols [FcC(OH)(R)CH2NH2] (R = Me, Et, nPr, iPr, Ph, p-MeOC6H4, o-ClC6H4, m-ClC6H4, p-ClC6H4, Fc; Fc = C5H4FeC5H5) were prepared by the reduction of cyanohydrin trimethylsilyl ethers of acylferrocenes with lithium aluminum hydride. All new compounds were characterised by elemental analysis, IR and 1H NMR spectroscopies. The X-ray crystal structure of β-amino-α,α-diferrocenylethanol shows that it has a polymeric chain structure with hydrogen bonding interactions between the OH proton and the N of NH2.

PSEUDACONITINE, AND THE STEREOCHEMICAL RELATIONSHIP OF THE HIGHLY OXYGENATED ACONITE ALKALOIDS

1963 ◽  
Vol 41 (6) ◽  
pp. 1485-1489 ◽  
Author(s):  
Y. Tsuda ◽  
Léo Marion
Keyword(s):  
Acetic Acid ◽  
Absolute Configuration ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Reduction Product ◽  
Lithium Aluminum ◽  
Partial Hydrolysis ◽  
Previous Knowledge ◽  
Relationship Of ◽  
Hydrolysis Of

An alkaloid isolated from Aconitum spicatum Stapf has been found to be identical not only with the originally described pseudaconitine but also with 'α-pseudaconitine'. The product of the partial hydrolysis of the base, i.e., veratroylpseudaconine, is dextrorotatory, and not laevorotatory as recorded in the old literature. On heating, pseudaconitine undergoes pyrolysis, loses the elements of acetic acid, and gives rise to pyropseudaconitine. This substance, on treatment with lithium aluminum hydride, is converted to demethoxyisopyropseudaconine which is identical with the Wolff–Kishner reduction product of pyraconine. This correlation establishes that pseudaconitine and aconitine possess the same absolute configuration, which, in the light of previous knowledge, is extended also to indaconitine, delphinine, mesaconitine, and jesaconitine.

scholarly journals Chiral Resolution and Absolute Configuration of 3α,6β-Dicinnamoyloxytropane and 3α,6β-Di(1-ethyl-1H-pyrrol-2-ylcarbonyloxy)tropane, Constituents of Erythroxylum Species

2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Marcelo A. Muñoz ◽  
Solange Arriagada ◽  
Pedro Joseph-Nathan
Keyword(s):  
Stationary Phase ◽  
Natural Product ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Normal Phase ◽  
Vibrational Circular Dichroism ◽  
Chiral Resolution ◽  
Case Characteristic ◽  
The Absolute

Chiral resolution of (±)-3α,6β-dicinnamoyloxytropane (1) and (±)-3α,6β-di(1-methyl-1 H-pyrrol-2-ylcarbonyloxy)tropane (2), prepared by esterification of (±)-3α,6β-tropanediol (3), was achieved using an amylose-derived HPLC stationary phase and normal phase conditions. The corresponding vibrational circular dichroism (VCD) spectra provided the absolute configuration of the enantiomers as (-)-(3 R,6 R)-1, (+)-(3S,6S)- 1, (-)-(3 R,6 R)-2 and (+)-(3S,6S)- 2. In each case, characteristic VCD bands for the absolute configuration determination of the 3α,6β-tropandiol esters were observed. While the absolute configuration of natural 1, previously isolated from Erythroxylum hypericifolium, could not be established due to the lack of literature optical rotation values, that of catuabine E, previously isolated from E. vacciniifolium, is now assigned as (-)-(3 R,6 R)-2 by comparison with the optical rotation values of the prepared samples and the reported rotation of the natural product.

scholarly journals Absolute Stereochemistry of the β-Hydroxy Acid Unit in Hantupeptins and Trungapeptins

2016 ◽  
Vol 11 (1) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Deepak Kumar Gupta ◽  
Gary Chi Ying Ding ◽  
Yong Chua Teo ◽  
Lik Tong Tan
Keyword(s):  
Amino Acid ◽  
Structural Feature ◽  
Absolute Configuration ◽  
Hydroxy Acid ◽  
Hplc Analysis ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Common Structural Feature ◽  
Acid Unit

The β-hydroxy/amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxy acid moieties in hantupeptins and trungapeptins were determined through their synthesis and HPLC analysis of the Mosher ester derivatives. Synthesis of two3-hydroxy-2-methyloctanoic acid (Hmoa) stereoisomers, (2 S,3 R)-Hmoa and (2 S,3 S)-Hmoa, were achieved using diastereoselective asymmetric method and the retention times of all four Hmoa isomers were established indirectly by RPLC-MS analysis of their Mosher ester derivative standards. Based on the retention times of the standards, the absolute configuration of the Hmoa unit in hantupeptin C (3) and trungapeptin C (6) was assigned as (2 R,3 S)- and (2 S,3 R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of β-hydroxy acid units in depsipeptides.

Diglyme as Solvent in the Gasometric Determination of Silanols by the Lithium Aluminum Hydride Method.

1963 ◽  
Vol 35 (9) ◽  
pp. 1308-1310 ◽  
Author(s):  
G. H. Barnes ◽  
N. E. Daughenbough
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Hydride Method

scholarly journals Determination of the Absolute Stereochemistry of Limonene and α-Santalol by Raman Optical Activity Spectroscopy

2012 ◽  
Vol 7 (4) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Akira Sakamoto ◽  
Nao Ohya ◽  
Toshio Hasegawa ◽  
Hiroaki Izumi ◽  
Nakako Tokita ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Optical Activity ◽  
Absolute Configuration ◽  
Natural Compounds ◽  
Vibrational Circular Dichroism ◽  
Raman Optical Activity ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Absolute Stereochemistry

Determining the absolute stereochemistry of organic compounds in solution remains a challenge. We investigated the use of Raman optical activity (ROA) spectroscopy to address this problem. The absolute configurations of (+)-( R)- and (-)-( S)-limonene were determined by ROA spectroscopy, which can be applied to smaller amounts of sample as compared with vibrational circular dichroism (VCD) spectroscopy. This ROA method was also applied to (+)-( E)-α-santalol and shown to be successful in the determination of the absolute configuration of this compound. ROA spectroscopy shows promise as a useful tool for determining the absolute stereochemistry of many natural compounds.

ChemInform Abstract: A Simple, Direct, and Reproducible Method for the Determination of Lithium Aluminum Hydride.

ChemInform ◽  
2010 ◽  
Vol 23 (20) ◽  
pp. no-no
Author(s):  
E. BROWN ◽  
A. LEZE ◽  
J. TOUET
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Reproducible Method
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