The reaction between 2,2-diphenyl-1-picrylhydrazyl and bromine

1980 ◽  
Vol 58 (7) ◽  
pp. 723-726 ◽  
Author(s):  
Patricia F. Currie ◽  
J. Wilson Quail ◽  
John A. Weil
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Elemental Analysis ◽  
Room Temperature ◽  
Controlling Factors ◽  
Experimental Conditions ◽  
Layer Chromatography

The reaction between 2,2-diphenyl-1-picrylhydrazyl and bromine in solution bas been studied at several temperatures. Despite the literature, reporting simple phenyl bromination products, a substantial yield of nitration products is observed. These have been identified by use of thin-layer chromatography, mass spectrometry, nuclear magnetic resonance, and elemental analysis. Among various products, 2-(p-nitrophenyl)-2-phenyl-1-picrylhydrazine is a major one at room temperature and above. It is thought that this compound is formed by reaction of DPPH with NO2, displaced from ortho nitro groups in the picryl rings by bromine. Yields were found to vary, depending on experimental conditions, with the temperature and the rate of bromine addition as primary controlling factors.

Structure of pithecolobine. III. The synthesis of the 1,5- and 1,3-desoxypithecolobines

1968 ◽  
Vol 46 (23) ◽  
pp. 3617-3624 ◽  
Author(s):  
K. Wiesner ◽  
Z. Valenta ◽  
D. E. Orr ◽  
V. Liede ◽  
G. Kohan
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
General Formula ◽  
Vapor Phase ◽  
The Individual ◽  
Layer Chromatography ◽  
Nuclear Magnetic

The second communication of this series has shown that "pithecolobine" is a family of closely related analogues represented by the general formula 1. In the present paper a crude semiquantitative estimate of the individual components is achieved by a combination of vapor-phase chromatography and chemical degradation.The synthesis of the desoxypithecolobines 3a and 3b and their tetratosylates 11a and b11b is described. A comparison of these compounds with the corresponding "natural" mixtures by thin-layer chromatography in several systems, infrared, nuclear magnetic resonance, and mass spectrometry was found to support strongly the conclusions reached by the previous degradative work.

THE STRUCTURE OF RETAMINE AND THE PARTIAL SYNTHESIS OF THE (−)-ENANTIOMORPH

1965 ◽  
Vol 43 (7) ◽  
pp. 2012-2016 ◽  
Author(s):  
Kju Hi Shin ◽  
L. Fonzes ◽  
Léo Marion
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Opposite Sign ◽  
Optical Rotation ◽  
Partial Synthesis ◽  
Dehydration Product ◽  
Layer Chromatography ◽  
Nuclear Magnetic

Previous work by many authors has led to the assumption that retamine might be (+)-12-hydroxysparteine. A partial synthesis of the enantiomorph of this compound has been effected by dehydration of (+)-13-hydroxylupanine and hydroboration of the product. The dehydration product consisted of two components that were separated by thin-layer chromatography and identified by the characteristics of their nuclear magnetic resonance (n.m.r.) spectra as Δ12,13-and Δ13,14-dehydrolupanine. Hydroboration of the Δ12,13-isomer gave rise to (−)-12-hydroxy-sparteine having, in thin-layer chromatography, the same Rf value as natural retamine and the same optical rotation numerically, although of opposite sign. The synthetic base had the same infrared and n.m.r. spectra as the alkaloid and the two had superimposable Debye–Scherrer patterns. Evidence is given showing the hydroxyl to be equatorial.

scholarly journals Metabolic Profiling of Saponin-Rich Ophiopogon japonicus Roots Based on 1H NMR and HPTLC Platforms

Planta Medica ◽  
2019 ◽  
Vol 85 (11/12) ◽  
pp. 917-924 ◽  
Author(s):  
Yanhui Ge ◽  
Xiaojia Chen ◽  
Dejan Gođevac ◽  
Paula C. P. Bueno ◽  
Luis F. Salomé Abarca ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
High Performance ◽  
Resonance Spectroscopy ◽  
Layer Chromatography ◽  
Nuclear Magnetic

AbstractIdeally, metabolomics should deal with all the metabolites that are found within cells and biological systems. The most common technologies for metabolomics include mass spectrometry, and in most cases, hyphenated to chromatographic separations (liquid chromatography- or gas chromatography-mass spectrometry) and nuclear magnetic resonance spectroscopy. However, limitations such as low sensitivity and highly congested spectra in nuclear magnetic resonance spectroscopy and relatively low signal reproducibility in mass spectrometry impede the progression of these techniques from being universal metabolomics tools. These disadvantages are more notorious in studies of certain plant secondary metabolites, such as saponins, which are difficult to analyse, but have a great biological importance in organisms. In this study, high-performance thin-layer chromatography was used as a supplementary tool for metabolomics. A method consisting of coupling 1H nuclear magnetic resonance spectroscopy and high-performance thin-layer chromatography was applied to distinguish between Ophiopogon japonicus roots that were collected from two growth locations and were of different ages. The results allowed the root samples from the two growth locations to be clearly distinguished. The difficulties encountered in the identification of the marker compounds by 1H nuclear magnetic resonance spectroscopy was overcome using high-performance thin-layer chromatography to separate and isolate the compounds. The saponins, ophiojaponin C or ophiopogonin D, were found to be marker metabolites in the root samples and proved to be greatly influenced by plant growth location, but barely by age variation. The procedure used in this study is fully described with the purpose of making a valuable contribution to the quality control of saponin-rich herbal drugs using high-performance thin-layer chromatography as a supplementary analytical tool for metabolomics research.

Isolation and Characterization of the Photoalteration Products of cis- and trans-Chlordane

1975 ◽  
Vol 58 (1) ◽  
pp. 6-9
Author(s):  
Francis I Onuska ◽  
Michael E Comba
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
High Yield ◽  
Isolation And Characterization ◽  
The Individual ◽  
Cis And Trans ◽  
Layer Chromatography

Abstract Ultraviolet irradiation of cis- and trares-chlordane yielded 3 photolysis products. The expected half-caged analog of cis-chlordane was formed in high yield, and 2 minor photoproducts of trans-chlordane were observed. One of these products was a half-caged isomer. The individual photoproducts were isolated by thin layer chromatography and characterized by infrared, nuclear magnetic resonance, and mass spectrometry.

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