The effect of ortho and para substituents on the formation of the E and Z isomers of the arylhydrazones obtained from diazonium coupling with methyl 3-aminocrotonate and 3-aminocrotononitrile

Reaction of arene diazonium salts with 3-aminocrotononitrile or methyl 3-aminocrotonate affords the 2-aryl-hydrazono-3-oxobutanenitrile (1 or 3 and 3′) or the methyl 2-arylhydrazono-3-oxobutanoate (2 and 2′ or 4 and 4′). A series of these hydrazones has been prepared with a range of electron-withdrawing and -donating substituents in the ortho or para position of the aryl moiety. The hydrazones have been characterized by spectroscopic methods, with emphasis on the 1H NMR spectra, which have been used to determine the configuration of the hydrazones as E or Z or a mixture of the two. The para-substituted hydrazononitriles (1) are formed as a single species, namely the Z isomer, whereas the ortho isomers are formed as a mixture of E and Z configurations (3 and 3′). The hydrazonobutanoates (2 and 2′ or 4 and 4′) are formed as E/Z mixtures regardless of the position of the substituent in the aryl moiety. Complete assignments of all signals in the 1H NMR spectra have been made on the basis of the ability of the various substituents to participate in intramolecular hydrogen bonding and a mechanism is proposed to account for the variations in the proportions of E and Z isomers and the effect of the nature of the substituent on this ratio. 13C NMR spectra of selected hydrazones have been recorded as an aid to structure assignment. Key words: hydrazone, diazonium, NMR spectroscopy, E/Z isomers, crotonic acid derivatives.

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Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811913 ◽

1981 ◽

Vol 46 (8) ◽

pp. 1913-1929 ◽

Cited By ~ 3

Author(s):

Bohdan Schneider ◽

Pavel Sedláček ◽

Jan Štokr ◽

Danica Doskočilová ◽

Jan Lövy

Keyword(s):

Ethylene Glycol ◽

Vibrational Spectra ◽

Nmr Spectra ◽

Coupling Constants ◽

Conformational Structure ◽

Infrared And Raman Spectra ◽

H Nmr ◽

Liquid States ◽

Crystalline Forms ◽

C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

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Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20061470 ◽

2006 ◽

Vol 71 (10) ◽

pp. 1470-1483 ◽

Cited By ~ 3

Author(s):

David Šaman ◽

Pavel Kratina ◽

Jitka Moravcová ◽

Martina Wimmerová ◽

Zdeněk Wimmer

Keyword(s):

Analytical Data ◽

Chiral Hplc ◽

Nmr Analysis ◽

Target Structure ◽

Enantiomerically Pure ◽

Whole Cells ◽

H Nmr ◽

Structure Assignment ◽

Related Compounds ◽

C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

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E-Homolupane Derivatives Substituted in Position 17 and 22a. 1H NMR, 13C NMR and IR Spectra

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950619 ◽

1995 ◽

Vol 60 (4) ◽

pp. 619-635 ◽

Cited By ~ 1

Author(s):

Václav Křeček ◽

Stanislav Hilgard ◽

Miloš Buděšínský ◽

Alois Vystrčil

Keyword(s):

Nmr Spectra ◽

2D Nmr ◽

Coupling Constants ◽

Side Chain ◽

Oxidation Reactions ◽

H Nmr ◽

Complete Assignment ◽

Nmr Techniques ◽

Intramolecular Association ◽

C Nmr

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.

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A Natural Triglyceride from the Methanol Root Extract of Cyphostemma Adenocaule (Steud. Ex A. Rich.) Wild & R.B.Drumm

10.26434/chemrxiv.13296539 ◽

2020 ◽

Author(s):

Abdulbasit Haliru Yakubu ◽

Iliya Ibrahim ◽

Abdulqadir bukar bababe ◽

Hassan Yesufu ◽

mohammed Garba Tom

Keyword(s):

Mobile Phase ◽

Nmr Spectra ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Solvent System ◽

Root Extract ◽

H Nmr ◽

Signal Peak ◽

Methylene Group ◽

C Nmr

Cyphostemma adenocaule (Steud. ex A. Rich.) is one of the specie plant that belongs to the family vitacea. In this study, Trilinolein was isolated and characterized from the methanol root extract of the plant. Column chromatography over silica gel granules as the stationary phase and eluted with a mobile phase mixture of n-Hex-EtA; EtA-CHCL3 and CHCL3-MeOH with gradient increasing polarity, followed by a second column using saphadex-LH20 and 100% MeOH as stationary and mobile phase vehicle respectively. TLC was developed with EtA 15: CHCL3 8: MeOH 4: H2O 1 as solvent system; sprayed with 10% H2SO4 ,Vanillin-sulphuric acid, and/ or Polyethylene glycol PEG and heat for spot detection and confirmation of bioactive principles. Compound CA1 was obtained and purified with CHCL3 to give a yellow semi-solid compound (0.23g). The 1H-NMR spectra showed 9 different signals; a signal peak of a glycerol (-CH2OCOR-) moiety on the first α-C chain and on the third αʹ-C at 4.143-4.187ppm and 4.296-4.325ppm respectively, while that of a β glycerol (-CHCOR-) at 5.286ppm. Signals of an allylic methylene group at 2.023-2.035ppm, Olefenic hydrogen group at signal peak of 5.362ppm and a diallylic methylene group at signal 2.790ppm were also observed. In the 13C NMR spectra of compound CA1, 57 carbon atoms where observed, multiple signals overlapping at a range of 14.13-34.21ppm corresponding to the aliphatic CH3 (C18), CH2 (C2, C3, C4, C5, C6, C7, C15, C16, and C17) and allylic (C8, C14) carbon atoms. Signals at 127.90-130.24ppm were assigned to the olefienic C atoms (C9, C10, C12, and C13) while signal of 172.87ppm and 173.32ppm were assigned to the carbonyl (C=O) carbon atoms (C1 and C2) respectively (Table 2). Analysis with DEPT-135, H-H COSY, HMBC and HSQC assignments of CA1 augments assignment of signals made for CA1 from 1H-NMR and 13C-NMR and corresponded to that of Trilinolein (<a href="https://pubchem.ncbi.nlm.nih.gov/#query=C57H98O6">C57H98O6</a>, MW 879.4 g/mol). The isolated compound was positive for the acrolein test for triglycerides; fat & oil and had an IC50 of 46.08µg/ml radical scavenging activity.

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Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.14.280 ◽

2018 ◽

Vol 14 ◽

pp. 3011-3017

Author(s):

Akın Sağırlı ◽

Yaşar Dürüst

Keyword(s):

Nmr Spectra ◽

2D Nmr ◽

Synthetic Route ◽

X Ray ◽

H Nmr ◽

2D Nmr Spectra ◽

Tof Ms ◽

C Nmr

The present work describes an unfamiliar reaction of 5-(chloromethyl)-3-substituted-phenyl-1,2,4-oxadiazoles with KCN affording trisubstituted 1,2,4-oxadiazol-5-ylacetonitriles and their parent alkanes, namely, 1,2,3-trisubstituted-1,2,4-oxadiazol-5-ylpropanes. To the best of our knowledge, the current synthetic route leading to decyanated products will be the first in terms of a decyanation process which allows the transformation of trisubstituted acetonitriles into alkanes by the incorporation of KCN with the association of in situ-formed HCN and most likely through the extrusion of cyanogen which could not be detected or isolated. In addition, the plausible mechanisms were proposed for both transformations. The structures of the title compounds were identified by means of IR, 1H NMR, 13C NMR, 2D NMR spectra, TOF–MS and X-ray measurements.

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New Synthetic Routes for 1-Benzyl-1,4,7,10-tetraazacyclododecane and 1,4,7,10-Tetraazacyclododecane-1-acetic Acid Ethyl Ester, Important Starting Materials for Metal-coded DOTA-Based Affinity Tags

Zeitschrift für Naturforschung B ◽

10.1515/znb-2007-0313 ◽

2007 ◽

Vol 62 (3) ◽

pp. 397-406 ◽

Cited By ~ 8

Author(s):

Stephan W. Kohl ◽

Katharina Kuse ◽

Markus Hummert ◽

Herbert Schumann ◽

Clemens Mügge ◽

...

Keyword(s):

Acetic Acid ◽

Ethyl Ester ◽

Nmr Spectra ◽

Acid Ethyl Ester ◽

Affinity Tags ◽

X Ray ◽

H Nmr ◽

Synthetic Routes ◽

New Compounds ◽

C Nmr

Two improved routes to synthesize 1-benzyl-1,4,7,10-tetraazacyclododecane (6) and 1,4,7,10- tetraazacyclododecane-1-acetic acid ethyl ester (11) are described as well as the synthesis of 1-{2-[4-(maleimido-N-propylacetamidobutyl)amino]-2-oxoethyl}-1,4,7,10-tetraazacyclododecane- 4,7,10-triacetic acid (17) and its Y, Ho, Tm, and Lu complexes. The 1H and 13C NMR spectra of the new compounds as well as the single crystal X-ray structure analyses of the intermediates 4-benzyl-1,7-bis(p-toluenesulfonyl)diethylenetriamine (3) and 1,4,7-tris(p-toluenesulfonyl)diethylenetriamine (7) are reported and discussed. The rare earth complexes of 17 have been characterized by 1H NMR spectroscopy and MALDI-TOF mass spectrometry.

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Direct observation of low spin – high spin electronic ground states and cross-over exchange in manganocene derivatives, (η5-C5H4R)2Mn, R = H, CH3, C2H5 by paramagnetic nuclear magnetic resonance

Canadian Journal of Chemistry ◽

10.1139/v86-014 ◽

1986 ◽

Vol 64 (1) ◽

pp. 71-75 ◽

Cited By ~ 14

Author(s):

Daniel Cozak ◽

François Gauvin ◽

Jacques Demers

Keyword(s):

Nmr Spectra ◽

Spin Exchange ◽

Exchange Process ◽

Paramagnetic Species ◽

Temperature Range ◽

H Nmr ◽

Low Field ◽

Spin Electronic ◽

Electronic Ground ◽

C Nmr

The paramagnetic 1H nmr spectra for manganocene (1) and 1.1′-dimethylmanganocene (2), and the 13C nmr spectra for 1,1′-diethylmanganocene (3) have been recorded in toluene solvent over a −90 to 90 °C temperature range. 1 shows a low field and a high field ring proton resonance in its spectrum near −59 °C. At higher temperatures the low field resonance is prevalent and becomes gradually averaged due to a fast spin exchange process that dominates the spectrum at 90 °C. For the ring substituted derivatives 2 and 3, resonances due to only one paramagnetic species were detected in the low temperature range. Above ambient temperature a new spectrum due to rapid spin exchange averaging is observed for these complexes. Results are readily interpreted in terms of ground state molecular cross-over exchanges between the 2E2g, 6A1g, and 2A1g spin states of the complexes.

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13C-NMR-Spektroskopie an polycyclischen Aromaten, II. Die 13C-NMR-Spektren von 1- und 2-Fluornaphthalin. Überprüfung der Signalzuordnung und Untersuchung der Substituenteneffekte auf die chemischen Verschiebungen / 13C NMR Spectroscopy of Polycyclic Aromatics, II. The 13C NMR Spectra of 1- and 2-Fluoronaphthalene. Reexamination of Signal Assignments and Investigation of Substituent Effects on Chemical Shifts

Zeitschrift für Naturforschung B ◽

10.1515/znb-1975-9-1026 ◽

1975 ◽

Vol 30 (9-10) ◽

pp. 788-793 ◽

Cited By ~ 14

Author(s):

Ludger Ernst

Keyword(s):

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

Double Resonance ◽

Substituent Effects ◽

13C Nmr Spectroscopy ◽

Polycyclic Aromatics ◽

H Nmr ◽

Iterative Analysis ◽

C Nmr

During a reinvestigation of the 13C NMR spectra of 1-fluoronaphthalene (1) and of 2-fluoronaphthalene (2) at 20 and 25.16 MHz, uncertainties that existed in the literature about signal assignments for 1 could be cleared. In the spectral analyses for 2 given so far, five out of ten signals were incorrectly assigned. The corrected assignment is supported by extensive 13C{1H} double resonance experiments, by recording of proton-coupled 13C and 13C{19F} spectra and by off-resonance 13C{1H} noise-decoupling. The results show a strong + M-effect of the fluorine substituents on 13C chemical shifts similar to the effects of OH and OCH3 groups. 1H NMR spectra of 1 and 2 could be partially assigned by decoupling of the 19F resonances and by iterative analysis.

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Metall-π-Komplexe yon Benzolderivaten, XIII Bis(methylthio-η-beiizol)chrom(0) Darstellung und Einsatz als zweizähniger Chelatligand/ Metal-π Complexes of Benzene Derivatives, XIII Bis(methylthio-η-benzene)chromium(0) Preparation and Function as a Bidentate Chelating Ligand

Zeitschrift für Naturforschung B ◽

10.1515/znb-1981-0120 ◽

1981 ◽

Vol 36 (1) ◽

pp. 94-101 ◽

Cited By ~ 9

Author(s):

Helmut Burdorf ◽

Christoph Eischenbroich

Keyword(s):

Nmr Spectra ◽

Room Temperature ◽

Radical Cations ◽

Esr Spectra ◽

Benzene Derivatives ◽

Consecutive Reaction ◽

H Nmr ◽

Chelating Ligand ◽

And Function ◽

C Nmr

Abstract The thioanisole-π-complexes (methylthio-η-benzene)-(η-benzene)-chromium (2) and bis(methylthio-η-benzene)chromium (3) have been prepared via lithiation of bis(η-benzene)-chromium and consecutive reaction with dimethyldisulfide. 1H NMR and 13C NMR spectra of 2 and 3 as well as ESR-spectra of the corresponding radical cations 2.+ and 3.+ were recorded and analyzed. In contrast to C(η-arene)-Si and C(η-arene)-P bonds, C(y-arene)-S bonds are stable to solvolysis. With (norbornadiene)tetracarbonylmolybdenum, 3 readily forms [bis(methylthio-η-benzene)chromium]tetracarbonylmolybdenum (6) wherein 3 functions as a chelating ligand. 1H and 13C NMR evidence suggests, that at room temperature 6 undergoes rapid conformational interconversions.

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Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a 1H/13C NMR Approach

Zeitschrift für Naturforschung B ◽

10.1515/znb-1987-0107 ◽

1987 ◽

Vol 42 (1) ◽

pp. 31-36 ◽

Cited By ~ 3

Author(s):

Erhard T. K. Haupt ◽

Heindirk tom Dieck ◽

Panayot R. Bontchev

Keyword(s):

Hydrogen Bond ◽

Intramolecular Hydrogen Bond ◽

13C Nmr ◽

Nmr Spectra ◽

Complete Analysis ◽

Solution Structures ◽

The Stability ◽

Intramolecular Hydrogen ◽

Related Compounds ◽

C Nmr

AbstractThe complete analysis of the 1H/13 C NMR spectra of α-Pyrophthalone and related compounds demonstrates that the earlier static planar description of the molecules is invalid for polar sol-vents, and here the stability of any intramolecular hydrogen bond is small.

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