9α-Hydroxyparthenolide from Zoegea baldschuanica C. WINKL. and its absolute configuration

1984 ◽  
Vol 49 (3) ◽  
pp. 637-641 ◽  
Author(s):  
Miloš Buděšínský ◽  
David Šaman ◽  
Gerard Nowak ◽  
Bohdan Drożdż ◽  
Miroslav Holub
Keyword(s):  
Absolute Configuration ◽  
Cd Spectra ◽  
H Nmr ◽  
Aerial Parts ◽  
Nmr Data

From the aerial parts of Zoegea baldschuanica C. WINKL. was isolated 9α-hydroxyparthenolide (I), whose absolute configuration was established on the basis of CD spectra. 1 H NMR data for I, parthenolide (VI) and the derivatives III and IV are discussed.

scholarly journals A New Bisabolene from Stevia tomentosa

2011 ◽  
Vol 6 (9) ◽  
pp. 1934578X1100600
Author(s):  
Alejandro Valdez-Calderón ◽  
J. Martín Torres-Valencia ◽  
J. Jesús Manríquez-Torres ◽  
René Velázquez-Jiménez ◽  
Mario A. Gómez-Hurtado ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Coupling Constants ◽  
Spectral Studies ◽  
Dihedral Angles ◽  
Model Compounds ◽  
H Nmr ◽  
Aerial Parts ◽  
The Absolute

The new sesquiterpene (1 R,2 R,3 R,6 R,7 S)-1-acetoxy-2,3-dmydroxy-2,3-dihydrobisabolene (3) together with ten known terpenes and three known flavonoids were isolated from the aerial parts and from the roots of Stevia tomentosa. The structure of 3 follows from spectral studies, the relative chirality at C-3 follows from 1H NMR coupling constants comparison with the corresponding calculated values obtained by applying a generalized Karplus-type relationship to the dihedral angles of model compounds, and the absolute configuration is assumed in analogy to known (2 R,3 R,6 R,7 S)-2,3-epoxy-2,3-dihydrobisabolen-1-one (2).

Juglomycins G-J: Isolation from Streptomycetes and Structure Elucidation

2005 ◽  
Vol 60 (2) ◽  
pp. 183-188 ◽  
Author(s):  
R. P. Maskey ◽  
H. Lessmann ◽  
S. Fotso ◽  
I. Grün-Wollny ◽  
H. Lackner ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Absolute Configuration ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
2D Nmr ◽  
Cd Spectra ◽  
Streptomyces Spp ◽  
Nmr Data ◽  
Related Compounds ◽  
Weak Antibacterial Activity

From the Streptomyces spp. 815 and GW4184, four new 4-juglon-2-ylbutyric acid derivatives, the juglomycins G - J (3a, 4a, 4c, 5c), have been isolated and characterised. The structures were derived from the 1D and 2D NMR data and mass spectra and confirmed by comparison with structurally related compounds. The absolute configuration was deduced from the CD spectra. The new natural products exhibited weak antibacterial activity similar to juglomycin A (5a).

Structure of isosilerolide, relative and absolute configuration of silerolide and lasolide - Sesquiterpenic lactones of new stereoisomeric type of eudesmanolides

1986 ◽  
Vol 51 (4) ◽  
pp. 903-929 ◽  
Author(s):  
Miroslav Holub ◽  
Miloš Buděšínský ◽  
Zdenka Smítalová ◽  
David Šaman ◽  
Urszula Rychłewska
Keyword(s):  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Nmr Data ◽  
Chemical Correlation ◽  
The Absolute

On the basis of spectroscopic, particularly 1H NMR data, isosilerolide was assigned structure I, including the absolute configuration. The structure was confirmed by X-ray diffraction. Isosilerolide represents a new stereoisomeric type of natural eudesmanolides, characterized as 5βH, 6αH, 7αH, 10αCH3-eudesman-6,12-olide. As shown by the chemical correlation of isosilerolide (I) with silerolide (III) and lasolide (X), the latter two natural lactones belong to this stereoisomeric group of eudesmanolides. Analysis of models and 1H NMR data shows that structures of some eudesman-6,12-olides, published by other authors, should be corrected.

Sesquiterpenic lactones of Inula aschersoniana JANKA var. aschersoniana species

1990 ◽  
Vol 55 (6) ◽  
pp. 1562-1567 ◽  
Author(s):  
Ełżbieta Błoszyk ◽  
Miloš Buděšínský ◽  
Włodzimierz M. Daniewski ◽  
Eva Pešková ◽  
Bohdan Drożdż ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Cd Spectroscopy ◽  
H Nmr ◽  
Aerial Parts ◽  
The Absolute

Aerial parts of species Inula aschersoniana JANKA var. aschersoniana have been shown to contain parthenolide (I), costunolide diepoxide (III) and the hitherto undescribed inusoniolide (IV) whose structure, including the absolute configuration, was determined using 1H NMR and CD spectroscopy.

scholarly journals Configurational Study of Diastereoisomeric Royleanone Diterpenoids From Salvia concolor

2019 ◽  
Vol 14 (7) ◽  
pp. 1934578X1986265
Author(s):  
Mónica Díaz-Fernández ◽  
María I. Salazar ◽  
Pedro Joseph-Nathan ◽  
Eleuterio Burgueño-Tapia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Absolute Configuration ◽  
Vibrational Circular Dichroism ◽  
Chemical Shift Assignments ◽  
Aerial Parts ◽  
Nmr Data ◽  
Nmr Chemical Shift Assignments ◽  
C Nmr

The known diterpenoids horminone (1) and taxoquinone (2) as a mixture, and pure 6,7-dehydroroyleanone (7) were isolated from the aerial parts of not yet studied Salvia concolor Lamb. Although 1 and 2 are known, the 1H Nuclear Magnetic Resonance (NMR) data of their acetyl derivatives 4 to 6 are only partially described. Moreover, the 13C NMR data assignments for 4 and 6 show some inconsistencies and reveal better agreement with those we obtained for diastereoisomeric 3 and 5. Since stereochemical aspects were in doubt, it was considered as mandatory to unambiguously determine the absolute configuration of 3 to 6 using vibrational circular dichroism spectroscopy, which then allowed the complete 1H and 13C NMR chemical shift assignments of 4 to 6.

Constituents of frontal gland secretion of peruvian termites Nasutitermes ephratae

1986 ◽  
Vol 51 (12) ◽  
pp. 2884-2895 ◽  
Author(s):  
Irena Valterová ◽  
Soňa Vašíčková ◽  
Miloš Buděšínský ◽  
Jan Vrkoč
Keyword(s):  
Absolute Configuration ◽  
Nmr Spectra ◽  
Phenylacetic Acid ◽  
Volatile Fraction ◽  
Cd Spectra ◽  
Model Compounds ◽  
Frontal Gland ◽  
Defense Secretion ◽  
H Nmr ◽  
Work Up

The defense secretion of Nasutitermes ephratae soldiers was analyzed and its constituents were identified. The volatile fraction contains monoterpenic hydrocarbons α-pinene, camphene, sabinene, β-pinene, myrcene, 4-carene, 3-carene, α-terpinene, limonene, γ-terpinene, β-phellandrene, and terpinolene. From the non-volatile fraction four alcohols derived from trinervitane skeleton were isolated: 1(15),8(19)-trinervitadien-3α-ol (I), 1(15),8(19)-trinervitadien-2β,3α-diol (II) and its 2α,3α- (III) and 2α,3β- (IV) isomers. 3α-Hydroxy-1(15),8(19)-trinervitadien-2-one (V), which was also isolated, is probably an artefact formed during the work-up of the extract. The structure of 3β-hydroxy-1(15),8(19)-trinervitadien-2-one (VI) was determined on the basis of mass, IR and 1H NMR spectra, comparison with model compounds and analogy with the literature. The absolute configuration of the trinervitane skeleton was studied by CD spectra of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)praseodymium complexes of the 2,3-diols II-IV and by the 1H NMR spectra of esters of the alcohol I with (R)- and (S)-α-methoxy-α-(trifluoromethyl)phenylacetic acid. The results obtained by both methods are identical and confirm the earlier suggested absolute configuration of the trinervitane skeleton.

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.

Preparation and absolute configuration at C(20) of 21-nor-5α-chol-22-en-24→20-olide derivatives

1981 ◽  
Vol 46 (4) ◽  
pp. 917-925 ◽  
Author(s):  
Vladimír Pouzar ◽  
Miroslav Havel
Keyword(s):  
Absolute Configuration ◽  
Nmr Spectra ◽  
Lithium Salt ◽  
H Nmr ◽  
Chemical Correlation ◽  
Unsaturated Lactones

Reaction of the aldehyde I with the lithium salt of 1-(2-tetrahydropyranyloxy)-2-propyne yielded the compounds II and IV. From the compound II the lactone XII was prepared via the intermediates III and X, the lactone XVIII was prepared from the substance IV via the intermediates V and XVI. The unsaturated lactones XII and XVIII were also prepared by sulfenylation and dehydrosulfenylation of the saturated lactones XIII and XIX. Based on chemical correlation and 1H-NMR spectra analyses of the compounds II and IV, the lactone XII was assigned the 20R-configuration whereas the lactone XVIII was allotted the 20S-configuration.

Synthesis and characteristics of ethylenediamine-N,N'-di-S-α-isovalerate and isomers of its cobalt(III) complexes

1982 ◽  
Vol 47 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Milan Strašák ◽  
František Bachratý ◽  
Jaroslav Majer
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Chemical Parameters ◽  
Methyl Group ◽  
Nmr Data ◽  
Physico Chemical ◽  
Natural Amino Acids ◽  
C Nmr

The synthesis and physico-chemical parameters are described of a new complexone based on natural amino acids, viz. ethylenediamine-N,N'-di-S-α-isovalerate (SS-EDDIV). 1H- and 13C-NMR data revealed that the methyl group in the substance are not equivalent. The isomers of the cobalt(III) complex with the asymmetric tetradentate SS-EDDIV ligand were prepared and separated; their characteristics are given. The absolute configuration of two of the five theoretically feasible isomers was determined based on their electronic absorption spectra and circular dichroism data.

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