NMR Determination of the Structure of Peracetylated Icariside B2 from Veratrum Lobelianum BERNH.

1995 ◽  
Vol 60 (8) ◽  
pp. 1380-1385 ◽  
Author(s):  
Václav Suchý ◽  
Miloš Buděšínský ◽  
Karel Ubik ◽  
Daniel Grančai ◽  
Vlasta Földešiová
Keyword(s):  
Detailed Analysis ◽  
Nmr Spectra ◽  
Aerial Part ◽  
C Nmr

rel(1S,4S,5R)-3,3,5-Trimethyl-4-[( 1E)-3-oxo-1-butenyl]-4,5-epoxy-cyclohexyl-O-β-D-glucopyranoside (I) was isolated from the aerial part of Veratrum lobelianum BERNH. The structure was derived mainly from detailed analysis of 1H and 13C NMR spectra of its acetylated derivative II. Compound I has been already reported under the name icariside B2in Epimedium grandiflorum MORR. var. thunbergianum (MIQ.) NAKAI.

Simple NMR Determination of 5α/5β Configuration of 3-Oxosteroids

2001 ◽  
Vol 66 (10) ◽  
pp. 1529-1544 ◽  
Author(s):  
Hana Chodounská ◽  
Miloš Buděšínský ◽  
Romana Šídová ◽  
Miroslav Šíša ◽  
Alexander Kasal ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Low Frequency ◽  
Simple Method ◽  
H Nmr ◽  
Steroid Skeleton ◽  
C Nmr

A simple method to distinguish the 5α- from the 5β-isomers of 3-oxosteroids based on low-frequency 1H NMR spectra was proposed. Additional 1H and 13C NMR characteristics were derived from the comparison of completely assigned spectra of the 5α- and 5β-isomers. The effect of substitution at different positions of steroid skeleton was evaluated on a series of isomeric 3-oxosteroids, prepared for this purpose.

The determination of the stereochemistry of epoxides located at the 5,6-positions of decalinic systems: An empirical method based on 13C NMR chemical shifts

2002 ◽  
Vol 80 (7) ◽  
pp. 774-778 ◽  
Author(s):  
Raquel M Cravero ◽  
Guillermo R Labadie ◽  
Manuel González Sierra
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Empirical Method ◽  
Nmr Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
Empirical Rule ◽  
C Nmr

The 13C NMR spectra of a series of 5,6-epoxides in decalinic systems were studied. The interpretation of the chemical shifts allowed us to formulate an empirical rule to predict the epoxide stereochemistry. A discussion of the scope and limitations of this method and its extension to larger carbon skeletons is also presented.Key words: epoxide stereochemistry, 13C NMR, NMR, decalinic systems, oxiranes.

Defensive substances from the frontal gland secretion of Nasutitermes nigriceps termite soldiers

1991 ◽  
Vol 56 (12) ◽  
pp. 2969-2977 ◽  
Author(s):  
Irena Valterová ◽  
Miloš Buděšínský ◽  
Jan Vrkoč
Keyword(s):  
Detailed Analysis ◽  
Infrared Spectra ◽  
Nmr Spectra ◽  
Gland Secretion ◽  
Volatile Fraction ◽  
Termite Species ◽  
Frontal Gland ◽  
Derivatives Of ◽  
Termite Soldiers ◽  
C Nmr

The components of the defence secretion of the soldiers of Nasutiterms nigriceps termite species (Isoptera: Termitidae: Nasutitermitinae) have been identified. In the volatile fraction the following components were found: α- and β-pinene, camphene, myrcene, α-terpinene, p-cymene, limonene and terpinolene. Ten diterpenic compounds (I - X), mostly derivatives of the tricyclic trinervitane, were found in the non-volatile fraction. The structure of the so far undescribed 1(15),8(19)-trinervitadiene-2β,3α,14α-triol triacetate (X) was determined on the basis of its mass and infrared spectra and a detailed analysis of 1H and 13C NMR spectra. Considerable differences were found in the composition of the non-volatile fraction of the secretion of the species of termites studied from various localities.

Preparation and properties of 2-(dialkylaminomethyl)cyclohexyl and 2-(dialkylaminomethyl)phenyl carbanilates

1990 ◽  
Vol 55 (7) ◽  
pp. 1854-1865 ◽  
Author(s):  
Alena Brádlerová ◽  
Nadežda Prónayová ◽  
Eva Mišíková ◽  
Ján Ďurinda
Keyword(s):  
Acute Toxicity ◽  
Elemental Analysis ◽  
Local Anaesthetic ◽  
Nmr Spectra ◽  
Analysis And Evaluation ◽  
C Nmr

A series of 2-(dialkylaminomethyl)cyclohexyl and 2-(dialkylaminomethyl)phenyl esters of substituted carbanilic acid have been prepared and their identity verified by elemental analysis and evaluation of IR and 13C NMR spectra. The spectral results have been used also for determination of isomerism of the starting 2-dialkylaminomethylcyclohexanols and final carbanilates. Local anaesthetic activity and acute toxicity have been tested with some of the substances.

scholarly journals An Experimental Study of the 4hJ(31P–31P) Coupling Constant and the 12C/13C Isotope Effect on 31P in an Iminophosphorane-Substituted Proton Sponge

2002 ◽  
Vol 2002 (1) ◽  
pp. 34-36
Author(s):  
José Elguero ◽  
Alain Fruchier ◽  
María Luisa Jimeno ◽  
Pedro Molina
Keyword(s):  
Experimental Study ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Sponge ◽  
Nmr Spectrum ◽  
13C Isotope ◽  
C Nmr

The 13C NMR spectra of the bromide of the protonated iminophosphorane -substituted sponge 7 were recorded at different fields. Together with the use of 13C satellites of the 31P NMR spectrum, these experiments allow determination of a reasonable set of chemical shifts and coupling constants. The most interesting are a 4h JPP = 1.6 Hz, determined directly from the 31P NMR spectrum, which probably involves the hydrogen bond, and a 2Δ31P(13C) isotope shift of 9 ppb.

Metallkomplexe mit biologisch wichtigen Liganden, XCVI [1] Palladium(II)-, Platin(II)-und Rhodium(I)-Komplexe mit (Phenyl)C-H···Metall-Wechselwirkung von Diphenylmethylen- glycinestern und von 2-Phenyloxazolinonen / Metal Complexes of Biologically Important Ligands, XCVI [1] Palladium(II), Platinum(II) and Rhodium(I) Complexes with (Phenyl)-C-H ··· Metal Interaction of Diphenylmethylene Glycine Esters and from 2-Phenyloxazolones

1997 ◽  
Vol 52 (10) ◽  
pp. 1199-1202 ◽  
Author(s):  
Bernhard Schreiner ◽  
Markus Prem ◽  
Werner Bauer ◽  
Kurt Polborn ◽  
Wolfgang Beck
Keyword(s):  
Metal Complexes ◽  
Nmr Spectra ◽  
Structural Determination ◽  
X Ray ◽  
Metal Interaction ◽  
Close Proximity ◽  
C Nmr

The reactions of Na2PdCl4, [(nBu3P)PtCl2]2, [(nBu3P)PdCl2]2 and [(C8H14)2RhCl]2/CO with diphenylmethylene glycine esters (L1) or 2-phenyl-4-R-oxazolones (L2) afford the complexes (nBu3P)(Cl)2Pt(L1), (OC)2(Cl)Rh(L1), Cl2Pd(L1)2 and (nBu3P)(Cl)2M(L2) (M = Pd, Pt), respectively. The X-ray structural determination of Cl2Pd(L1)2 and the 1H and 13C NMR spectra show a close proximity of the ortho phenyl-H-atom to the metal; the complexes are precursors for ortho metallation.

scholarly journals Configurational Study of an Aporphine Alkaloid from Annona purpurea

2018 ◽  
Vol 13 (7) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Julio C. Ontiveros-Rodríguez ◽  
Eleuterio Burgueño-Tapia ◽  
Javier Porras-Ramírez ◽  
Pedro Joseph-Nathan ◽  
L. Gerardo Zepeda
Keyword(s):  
Nitrogen Atom ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Optical Rotation ◽  
Vibrational Circular Dichroism ◽  
Aporphine Alkaloid ◽  
Stereogenic Center ◽  
First Time ◽  
C Nmr

Purpureine (1), norpurpureine (2), and 3-hydroxyglaucine (4) were isolated from the leaves of Annona purpurea. A vibrational circular dichroism study for the absolute configuration determination of 1 provides evidence for the mutually dependent atropisomerism, local chirality of the sole stereogenic center, and the geometry of the tetrahedral nitrogen atom in aporphine alkaloids. The observed change in the optical rotation sign between 2 and its hydrochloride 3 might explain why this compound has been reported as dextrorotatory and levorotatory from the same botanical source. Furthermore, 1H and 13C NMR spectra of 1, 2 and 4 were fully assigned for the first time.

Revision of nido-2,6-C2B7H11 to the arachno-4,5-C2B7H13 structure. Determination of the structure from NMR spectra and chemical origin

1988 ◽  
Vol 53 (11) ◽  
pp. 2742-2752 ◽  
Author(s):  
Stanislav Heřmánek ◽  
Tomáš Jelínek ◽  
Jaromír Plešek ◽  
Bohumil Štíbr ◽  
Jiří Fusek
Keyword(s):  
Structure Determination ◽  
Nmr Spectra ◽  
Open Face ◽  
C Nmr

The assymetric C2B7 carborane held until the present for 2,6-C2B7H11, is in reality the arachno-4,5-C2B7H13 carborane (I) with two adjacent B-H-B bridges, one BH2, one CH2 and one CH group in the hexagonal open-face. The arrangement of the boron network was determined on the basis of the 11B, 11B-11B COSY, 1H and 13C NMR spectra and on the T1(B) study. The connection of B- with C-skeletal atoms was deduced from the positions of deuterium in the deutero analogs prepared by the CH2O/D3O+ degradation of three selectively deuterated nido-[7,8-C2B9H12]- anions. A selective transmission of D from CD2O to the B(9) vertex in the course of the CD2O/D3O+ degradation was observed. The structure of arachno-4,5-C2B7H13 is consistent with the different pathways of its preparation.

13C NMR study of tetrosides and their derivatives

1980 ◽  
Vol 45 (10) ◽  
pp. 2779-2783 ◽  
Author(s):  
Jiří Urban ◽  
Miroslav Marek ◽  
Jiří Jarý ◽  
Petr Sedmera
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Direct Coupling ◽  
Coupling Constants ◽  
Anomeric Configuration ◽  
Nmr Study ◽  
C Nmr

13C NMR spectra of 23 tetrose derivatives were assigned. The C(1) resonates below 103 ppm with compounds having cis-arranged substituents at C(1) and C(2) and above 106 ppm with compounds having trans-arrangement. The carbon-13 chemical shifts are mainly influenced by the 1,2-interaction. The magnitudes of direct coupling constants 1J(C(1), H) cannot be used for the determination of the anomeric configuration.

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