Metabolites of bird's nest fungi. Part 4. The isolation and structure determination of cybullol, a metabolite of Cyathus bulleri Brodie

1976 ◽  
Vol 54 (6) ◽  
pp. 910-916 ◽  
Author(s):  
William A. Ayer ◽  
Michael G. Paice
Keyword(s):  
Magnetic Resonance ◽  
Absolute Configuration ◽  
Structure Determination ◽  
Mass Spectra ◽  
Fungal Metabolite ◽  
Physical Methods ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Magnetic Resonance Spectra

Cybullol, a metabolite of Cyathus bulleri Brodie, has been shown to be (2S,5S,6S,10S)-cis-6, trans-10-dimethyl-r-2-cis-5-decalindiol (1) by a combination of chemical and physical methods. The mass spectra and the 1H and 13C magnetic resonance spectra of cybullol and derivatives are discussed. The absolute configuration of cybullol was deduced from the circular dichroism spectrum of the ketol 3. Cybullol has been transformed into the fungal metabolite (−)-geosmin (11). This correlation establishes the absolute configuration of (−)-geosmin.

Étude conformationnelle de cétopipérazines: (I) 3R-méthyl-6-carbéthoxy-2 oxopipérazine, (II) 3R-[p-hydroxybenzyl]-6-carbéthoxy-2 oxopipérazine: I, II en solution et structure cristalline de II

1987 ◽  
Vol 65 (6) ◽  
pp. 1308-1312 ◽  
Author(s):  
André Michel ◽  
Guy Evrard ◽  
B. Norberg
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Absolute Configuration ◽  
Structure Determination ◽  
Opiate Receptor ◽  
Receptor Level ◽  
X Ray ◽  
Diastereomeric Mixture ◽  
The Absolute

The synthesis of the title compounds has been described recently. It was anticipated that the product would be a diastereomeric mixture. Surprisingly, only one isomer was obtained. The present work is an attempt to find the conformationnal properties accounting for those observations. X-ray structure determination of 3R-[p-hydroxybenzyl]-6-carbethoxy-2-oxopiperazine shows that the molecule adopts a folded conformation and that the absolute configuration at C6 is [R]. Investigation in solution using 1H nuclear magnetic resonance shows the existence of three conformers and discusses the relative populations. Those findings are also relevant in terms of the activity of such compounds at the opiate receptor level.

(-)-Strempeliopine, stereoselective total synthesis and the determination of absolute configuration

1986 ◽  
Vol 51 (8) ◽  
pp. 1731-1742 ◽  
Author(s):  
Josef Hájíček ◽  
Jan Trojánek
Keyword(s):  
Circular Dichroism ◽  
Total Synthesis ◽  
Absolute Configuration ◽  
Determination Of Absolute Configuration ◽  
Natural Base ◽  
The Absolute ◽  
Circular Dichroïsm

A synthesis of (±)-strempeliopine (II) is described, the key step of which is the stereoselective reductive rearrangement of 18-methylene-1,2-dehydroaspidospermidine (XI). The absolute configuration of the natural (-)-base II was determined as (2S, 7R, 20R, 21R) on the basis of its synthesis from (+)-18-methylenevincadifformine (XVII) the configuration of which was derived from a comparison of circular dichroism properties of bases with a β-anilinoacrylate chromophore. The biogenesis of the alkaloids of the schizozygane type is discussed.

Absolute configuration determination of theanti-head-to-head photocyclodimer of anthracene-2-carboxylic acid through cocrystallization withL-prolinol

2013 ◽  
Vol 69 (11) ◽  
pp. 1411-1413 ◽  
Author(s):  
Yuko Kawanami ◽  
Hidekazu Tanaka ◽  
Jun-ichi Mizoguchi ◽  
Nobuko Kanehisa ◽  
Gaku Fukuhara ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Circular Dichroism ◽  
Carboxylic Acid ◽  
Absolute Configuration ◽  
Void Space ◽  
Circular Dichroism Spectra ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Hydrogen Bonded

The absolute configuration has been established of the enantiopureanti-head-to-head cyclodimer of anthracene-2-carboxylic acid (AC) cocrystallized with L-propinol and dichloromethane [systematic name: (S)-2-(hydroxymethyl)pyrrolidin-1-ium (5R,6S,11R,12S)-8-carboxy-5,6,11,12-tetrahydro-5,12:6,11-bis([1,2]benzeno)dibenzo[a,e][8]annulene-2-carboxylate dichloromethane monosolvate], C5H12NO+·C30H19O4−·CH2Cl2. In the crystal structure, the AC dimer interacts with L-prolinol through a nine-membered hydrogen-bonded ring [R22(9)], while the dichloromethane molecule is incorporated to fill the void space. The absolute configuration determined in this study verifies a recent assignment made by comparing theoreticalversusexperimental circular dichroism spectra.

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.

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