1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Part III:* Vinclozolin

1986 ◽  
Vol 40 (6) ◽  
pp. 743-745 ◽  
Author(s):  
Alexander Hatzis ◽  
Robert Rothchild
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Optical Purity ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Chiral Reagent ◽  
H Nmr ◽  
Lanthanide Induced Shifts ◽  
Lanthanide Shift Reagents ◽  
Shift Reagents

The 60 MHz 1H NMR spectra of racemic vinclozolin, 1, have been studied at 28° in CDCI3 solution with the achiral reagent tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)- d-camphorato] europium(III), 3, and tris[3-(heptafluoropropylhydroxymethylene)- d-camphorato]europium(III), 4. Reagent 3 produced only small lanthanide-induced shifts and no observable enantiomeric shift differences, ΔΔδ, with 3:1 molar ratios as high as 1.40. In contrast, chiral reagent 4 produced substantial ΔΔδ for the proton, Hβ, at C-2 of the ethenyl group syn to the oxazolidinedione ring and smaller ΔΔδ for the anti proton, Hβ, at the above carbon and for the CH3. With a 4:1 molar ratio of 0.581, ΔΔδ of 7.0 Hz was seen for Hβ. A 4:1 ratio of about 0.41 should be optimum for optical purity determinations; as little as 5% of the minor enantiomer should be detectable.

Optical Purity Determination and 1H NMR Spectral Simplification with Lanthanide Shift Reagents III: Ethotoin, 3-Ethyl-5-Phenyl-2, 4-Imidazolidinedione

1984 ◽  
Vol 38 (5) ◽  
pp. 734-737 ◽  
Author(s):  
John Avolio ◽  
Robert Rothchild
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Optical Purity ◽  
Shift Reagent ◽  
Methine Proton ◽  
Molar Ratio ◽  
Purity Determination ◽  
H Nmr ◽  
Lanthanide Shift Reagents ◽  
Shift Reagents

The 60 MHz 1H NMR spectra of racemic ethotoin, a, have been studied with the achiral shift reagent tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimeth-yl-3,5-octanedionato) europium (III), b, and the chiral tris[3-(rrifluoromethylhydroxymethylene)- d-camphorato] europium (III), c Appreciable values of the enantiomeric shift difference, ΔΔδ, were observed for the NH, CH3, CH, and ortho aryl protons in CDCl3 solutions at 28°C with the use of samples about 045 molal in a Optical purity assays should be feasible with the use of the NH or CH3 absorptions that display ΔΔδ of 224 and 70 Hz, respectively, at a c:a molar ratio of about 03, with the former resonance being optimal With a c:a ratio between 04–05, the methine proton can be used, with ΔΔδ 11 – 13 Hz Results are interpreted in terms of major coordination of the europium at the C-2 oxygen

1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Part II: Ethosuximide, 3-Ethyl-3-Methyl-2,5-Pyrrolidinedione, and Comparisons with Analogs

1986 ◽  
Vol 40 (4) ◽  
pp. 531-537 ◽  
Author(s):  
John Avolio ◽  
Suzanne Thomson Eberhart ◽  
Robert Rothchild ◽  
Paul Simons
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Shift Reagent ◽  
Ethyl Group ◽  
Molar Ratios ◽  
H Nmr ◽  
Lanthanide Shift Reagents ◽  
Shift Reagents

The 60 MHz 1H NMR spectra of racemic ethosuximide, 1, have been studied in detail with the achiral shift reagent, tris(6,6,7,7,8,8,8-hepta-fiuoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, and the chiral tris(3-trifluoromethylhydroxymethylene)- d-camphorato]europium(III), 3. Enantiomeric shift differences, ΔΔδ, were clearly observed for the CH3 of the ethyl group of 1 at molar ratios of 3:1 as low as 0.0385, with ΔΔδ valaues of about 12 Hz seen at a 3:1 ratio of 0.340 for CDCl3 solutions at 28°, 0.634 molal in 1. Smaller ΔΔδ values were also seen for the quaternary methyl and for one of the hydrogens at C-4. Parallel studies with 2 were performed to support assignments. Results are compared with a group of important drugs that are structurally related, including ethotoin, mephenytoin, glutethimide, methsuximide, phensuximide, and paramethadione, in terms of steric and basicity effects. Correlations of both lanthanide-induced shift (Δδ) and ΔΔδ could generally be made from simple electronic considerations related to infrared carbonyl stretching frequencies. Of the 28 sets of Δδ values assigned for the substrates, 3 gave significantly larger values than 2 in only two cases.

Janus-type isopropyl groups revealed by 1H-NMR spectra of alkylpyridines with lanthanide shift reagents (LSR)

1985 ◽  
Vol 26 (38) ◽  
pp. 4673-4676 ◽  
Author(s):  
Cornelia Uncuta ◽  
Teodor-Silviu Balaban ◽  
Mircea D. Gheorghiu ◽  
Ligia Stănescu ◽  
Aurica Petride ◽  
...  
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Lanthanide Shift Reagents ◽  
Shift Reagents

Optical Purity Determination and 1H NMR Spectral Simplification with Lanthanide Shift Reagents: Glutethimide, 3-Ethyl-3-phenyl-2,6-piperidinedione, 1

1983 ◽  
Vol 37 (3) ◽  
pp. 292-296 ◽  
Author(s):  
Suzanne Eberhart ◽  
Robert Rothchild
Keyword(s):  
Aromatic Ring ◽  
Optical Purity ◽  
Shift Reagent ◽  
Coupling Constants ◽  
Line Broadening ◽  
Molar Ratios ◽  
H Nmr ◽  
A Value ◽  
Chiral Shift Reagent ◽  
Lanthanide Shift Reagents

The 60 MHz 1H NMR spectra of racemic glutethimide, 1, have been studied with the chiral shift reagent, tris[3-(trifluoromethylhydroxymethylene)- d-camphorato] europium(III), 2, and the achiral tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium(III), 3. Appreciable values of the enantiomeric shift difference, ΔΔδ, were observed at relatively low molar ratios of 2:1 for the CH3 group in CDCl3 solution at 28°C. Optical purity determinations should easily be carried out by using this absorption with a 2:1 ratio of approximately 0.25; 3 to 5% of one enantiomer should be detectable in a sample. Lanthanide-induced line broadening was relatively low, thereby facilitating these measurements. A substantial ΔΔδ was also observed for the ortho hydrogens of the aromatic ring and the NH. For example, at a 2:1 ratio of 0.254, the CH3 resonance displayed a value of ΔΔδ of 7.3 Hz (0.12 δ) and was free of overlap with the absorptions of the shift reagent, 2. The relative slopes of the plots of induced shift, Δδ, vs molar ratios of 2:1 or 3:1, as well as values of coupling constants, support assignments for the proton absorptions of the aromatic ring.

Effect of lanthanide shift reagents on 1H NMR spectra of aminopyridines

1979 ◽  
Vol 44 (3) ◽  
pp. 908-911 ◽  
Author(s):  
Antonín Lyčka ◽  
Dobroslav Šnobl
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Nmr Spectra ◽  
Pyridine Ring ◽  
Chemical Shifts ◽  
Amino Group ◽  
H Nmr ◽  
Lanthanide Shift Reagents

The effect of Eu(dpm)3 and Pr(dpm)3 on the proton spectra of 2-amino-, 3-amino- and 4-aminopyridines has been studied by the 1H NMR spectroscopy in tetrachlomethane and deuteriochloroform at 25 °C. Relative changes of the induced chemical shifts of pyridine carrying electron-donor substituents (amino group) are the same as the values given in literature for pyridine ring with electron-acceptor substituents.

Synthesis of 5-Cyano-3-(4-Chlorobutanoyl) Indole in 1-Buty-3-Methylimidazolium Chloroaluminate

2013 ◽  
Vol 575-576 ◽  
pp. 270-275
Author(s):  
Yun Xia Jiang ◽  
Hu Jin Zuo ◽  
Yong Jia Shen ◽  
Feng Ping Yi
Keyword(s):  
Ionic Liquid ◽  
Nmr Spectra ◽  
Major Product ◽  
Molar Ratio ◽  
Acylation Reaction ◽  
Molar Ratios ◽  
H Nmr

The Friedel-Crafts acylation reaction between 5-cyanoindole and 4-chlorobutyryl chloride was conducted in ionic liquid 1-buty-3-methylimidazolium chloroaluminate ([bmiCl/AlCl3), the major product was 5-cyano-3-(4-chlorobuty) indole. The structure of the product was characterized by Mass and1H NMR spectra. When the molar ratio of AlCl3to [bmiCl in [bmiCl/AlCl3is at 1:1 or less, no 5-cyano-3-(4-chlorobuty) indole could be obtained. The suitable molar ratios of AlCl3to [bmiCl in [bmiCl/AlCl3were from 2:1 to 3:1, the yields of the major product were from 68% to 70%, respectively. When the molar ratio of [bmiCl/AlCl3to 5-cyanoindole was less than 2:1, the acylation reaction was difficult to carry out, because 5-cyanoindole would be not totally dissolve in [bmiCl/AlCl3under the situation.

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