Determination of the Structure of Chlorobutyl and Bromobutyl Rubber by NMR Spectroscopy

1987 ◽  
Vol 60 (4) ◽  
pp. 636-646 ◽  
Author(s):  
Chia Yeh Chu ◽  
Kenneth Norman Watson ◽  
Rastko Vukov
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Broad Band ◽  
Type Structure ◽  
13C Nmr Spectra ◽  
Model Compounds ◽  
1H And 13C Nmr

Abstract An analysis of the 1H and 13C NMR spectra of the chlorobutyl and bromobutyl rubbers was performed. Peaks were assigned based on evidence from broad-band decoupled, off-resonance decoupled, selectively decoupled and J-modulated spectra, the known characterization of butyl rubber and halogenation studies on model compounds. The assignment of the minor peaks indicated that the exomethylene-type structure is predominant in both halogenated rubbers. They also contain some nonhalogenated isoprenyl units. Bromobutyl rubber also contains some α-bromomethyl-type structures resulting from rearrangement of the exomethylene structure. The presence of endo-type structures will require further study for confirmation.

Computer-aided determination of microfragmentary composition of organic molecule by mass-, 1H- and 13C-NMR spectra

1994 ◽  
Vol 18 (1) ◽  
pp. 81-88
Author(s):  
B.G. Derendyaev ◽  
K.S. Lebedev ◽  
S.A. Nekhorshev ◽  
S.P. Kirshansky
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Organic Molecule ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Computer Aided

scholarly journals Modeling of Antioxidant Activity, Polyphenols and Macronutrients Content of Bee Pollen Applying Solid-State 13C NMR Spectra

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1123
Author(s):  
Sylwester Mazurek ◽  
Roman Szostak ◽  
Mateusz Kondratowicz ◽  
Magdalena Węglińska ◽  
Agnieszka Kita ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Bee Pollen ◽  
Relative Standard ◽  
Solid State 13C Nmr

An application of solid 13C nuclear magnetic resonance (NMR) spectroscopy for the determination of macronutrients, total polyphenols content, antioxidant activity, N C S elements, and pH in commercially available bee pollens is reported herein. Solid-state 13C NMR spectra were recorded for homogenized pollen granules without chemical treatment or dissolution of samples. By combining spectral data with the results of reference analyses, partial least squares models were constructed and validated separately for each of the studied parameters. To characterize and compare the models’ quality, the relative standard errors of prediction (RSEP) were calculated for calibration and validation sets. In the case of the analysis of protein, fat and reducing sugars, these errors were in the 1.8–2.5% range. Modeling the elemental composition of bee pollen on the basis of 13C NMR spectra resulted in RSEPcal/RSEPval values of 0.3/0.6% for the sum of NHCS elements, 0.3/0.4% for C, 1.8/1.9% for N, and 4.2/6.1% for S quantification. Analyses of total phenolics and ABTS antioxidant activity resulted in RSEP values in the 2.7–3.5% and 2.8–3.8% ranges, respectively, whereas they were 1.4–2.1% for pH. The obtained results demonstrate the usefulness of 13C solid-state NMR spectroscopy for direct determination of various important physiochemical parameters of bee pollen.

Mestranol: The assignment of its 1H and 13C NMR spectra by means of two-dimensional NMR spectroscopy, and its photochemical decomposition

Steroids ◽  
1985 ◽  
Vol 45 (2) ◽  
pp. 101-118 ◽  
Author(s):  
Adrianus C.J. Sedee ◽  
Gerardus M.J. Beijersbergen van Henegouwen ◽  
Monique E. de Vries ◽  
Cornelis Erkelens
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Two Dimensional ◽  
1H And 13C Nmr ◽  
Photochemical Decomposition

scholarly journals Determination of C-23 Configuration in (20R)-23-Hydroxycholestane Side Chain of Steroid Compounds by 1H and 13C NMR Spectroscopy

2013 ◽  
Vol 8 (9) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Alla A. Kicha ◽  
Anatoly I. Kalinovsky ◽  
Alexander S. Antonov ◽  
Oleg S. Radchenko ◽  
Natalia V. Ivanchina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Side Chain ◽  
Side Chains ◽  
Model Compounds ◽  
1H And 13C Nmr ◽  
C 23 ◽  
C Nmr

Epimeric (20 R,23 R)- and (20 R,23 S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20 R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelifera and Lethasterias fusca was established.

Complete assignments in 1H and 13C NMR Spectra of uraphine and 6-oxocorumdephine using 2D NMR spectroscopy

2012 ◽  
Vol 48 (4) ◽  
pp. 717-718
Author(s):  
T. M. Gabbasov ◽  
E. M. Tsyrlina ◽  
L. V. Spirikhin ◽  
M. S. Yunusov
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
2D Nmr ◽  
13C Nmr Spectra ◽  
2D Nmr Spectroscopy ◽  
1H And 13C Nmr

Synthesis of Phosphatidylcholines Possessing Functionalized Acids at sn-2, and 13C–14N and 13C–31P Couplings in Their 13C NMR Spectra

Synlett ◽  
2020 ◽  
Vol 31 (07) ◽  
pp. 718-722
Author(s):  
Masao Morita ◽  
Shun Saito ◽  
Riku Shinohara ◽  
Ryohei Aoyagi ◽  
Makoto Arita ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectroscopy ◽  
13C Nmr Spectra ◽  
Epoxy Acids ◽  
Acid Acid ◽  
Standard Base ◽  
Acid Labile

Although 4-Me2NC5H4N (DMAP) is a standard base for esterification of (2-Me-6-NO2-C6H3CO)2O (MNBA), N-methylimidazole (NMI) was examined for the condensation of acids with 1-stearoyl-lysophosphatidylcholine because of the non-tailing nature of NMI on silica gel. Acids tested were EPA, α-linolenic acid, TBS ethers of 18-HEPE and ricinoleic acid, acid-labile epoxy acids, and a phenyldiynyl acid. The condensation proceeded well with these acids, and chromatographic separation of resulting phosphatidylcholines and remaining NMI was easily performed. During the characterization of the products by 13C NMR spectroscopy, 13C–14N and 13C–31P couplings were observed.

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