scholarly journals Novel Ecdysteroids fromSerratula wolffii

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Attila Ványolós ◽  
Zoltán Béni ◽  
Miklós Dékány ◽  
András Simon ◽  
Mária Báthori
Keyword(s):  
Methanolic Extract ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Nmr Methods ◽  
New Compounds ◽  
Ponasterone A

Two new and one known ecdysteroids were identified in the methanolic extract of the roots ofSerratula wolffii. The new compounds isolated were ponasterone A-22-apioside (1) and 3-epi-shidasterone (3), together with the known 3-epi-22-deoxy-20-hydroxyecdysone (2). The structures of compounds1–3were determined by extensive spectroscopic techniques, including one- and two-dimensional NMR methods.

scholarly journals Searching for a UV-filter in the eyes of high flying birds

2018 ◽  
Author(s):  
Malgorzata Zawadzka ◽  
Beatrix Ràcz ◽  
Dario Ambrosini ◽  
Carl Henrik Gørbitz ◽  
Jens Preben Morth ◽  
...  
Keyword(s):  
Aqueous Humor ◽  
High Field ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
High Altitudes ◽  
Chromatographic Purification ◽  
Uv Filter ◽  
Nmr Methods

AbstractAn ultraviolet (UV)-absorbing compound of unknown identity is present in the aqueous humor of geese and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as “compound X”, was fractionated and examined using a variety of spectroscopic techniques including LC-MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective “compound X”. It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.

scholarly journals 4-vinylpyridine derivatives: Protonation, methylation and silver(I) coordination chemistry

2021 ◽  
pp. 174751982198965
Author(s):  
Guoqi Zhang
Keyword(s):  
Mass Spectrometry ◽  
Schiff Base ◽  
Coordination Chemistry ◽  
Elemental Analysis ◽  
Silver Complex ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
X Ray Crystallography ◽  
Pyridine Moiety ◽  
New Compounds

( E)-4-[2-(Pyridin-4-yl)vinyl]benzaldehyde, containing both a 4-vinylpyridine and an aldehyde functionality, is utilized to develop new, highly conjugated chalcone compounds and a bis-Schiff base azine compound. The chalcone-containing compounds are further explored for their protonation, methylation and silver(I) coordination chemistry using the pyridine moiety. In parallel, a cyano-containing analogue, ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile is also synthesized and studied for its silver(I) coordination chemistry. These new compounds are fully characterized by mass spectrometry, elemental analysis and spectroscopic techniques. The methylated product of ( E)-1-(9-anthryl)-3-{4-[2-(pyridin-4-yl)vinyl]phenyl}prop-2-en-1-one and a silver complex of ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile are structurally determined by X-ray crystallography.

A Study of Methyl β-Xylobioside: An Illustrative Example of Two-Dimensional NMR Methods

1984 ◽  
Vol 3 (4) ◽  
pp. 513-524 ◽  
Author(s):  
William B. Wise ◽  
Philip E. Pfeffer ◽  
Pavol Ková
Keyword(s):  
Two Dimensional ◽  
Nmr Methods

scholarly journals Competitive Diels–Alder and ene addition of N-arylmaleimides to 7-dehydrocholesteryl acetate

1992 ◽  
Vol 70 (11) ◽  
pp. 2730-2744 ◽  
Author(s):  
William J. Leigh ◽  
Donald W. Hughes ◽  
D. Scott Mitchell
Keyword(s):  
Molecular Mechanics ◽  
Nmr Spectra ◽  
Benzene Solution ◽  
Diels Alder ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
A Minor ◽  
C Nmr ◽  
Alder Adduct ◽  
Ene Addition

Thermolysis of N-phenyl, N-para-biphenyl, and N-para, para′-terphenylmaleimide with 7-dehydrocholesteryl acetate in benzene solution at 200 °C yields mixtures of four cycloadducts in relative yields that are essentially independent of the maleimide substituent. The three major products are those of ene addition to C7 of the steroid with abstraction of the proton at C9 or C14. The α-endo-Diels-Alder adduct is formed as a minor product. The structures of the adducts have been elucidated on the basis of one- and two-dimensional 1H and 13C NMR spectroscopic techniques, including homonuclear 1H decoupling, NOE, 1H–1H COSY, heteronuclear 1H–13C shift correlation, and TOCSY 2-D experiments, and the results of molecular mechanics (MMX) calculations. The combination of these techniques has made it possible to almost completely assign the 1H and 13C NMR spectra for two of the ene adducts and the Diels–Alder adduct from reaction of 7-dehydrocholesteryl acetate with N-phenyl maleimide.

scholarly journals Synthesis, Characterization and Biological Activity Study of New Compounds Tetrazole Derivatives Azo-Schiff Base

2019 ◽  
Vol 25 (103) ◽  
pp. 68-89
Author(s):  
Hiba Ibrahim Abdulla AL-Joubory ◽  
Khalid Mohamad Motny Al-janaby
Keyword(s):  
Biological Activity ◽  
Schiff Base ◽  
Pathogenic Bacteria ◽  
Diazonium Salt ◽  
Aldehyde Group ◽  
Spectroscopic Techniques ◽  
Phenyl Hydrazine ◽  
Ft Ir ◽  
New Compounds ◽  
Tetrazole Derivatives

This work included synthesis of azo dye (H1) by the reaction of diazonium salt to sulfacetamide with 4-hydroxy benzaldehyde at (0-5) oC  and synthesis of schiff base (H2-H6) through reaction substituted aromatic amine (aniline, 4-nitro aniline, 4-chloro aniline, 4-amino benzoic acid and phenyl hydrazine)  with aldehyde group in azo compound (H1) in ethanol compounds (H2-H6) and tetrazole derivatives prepared by reaction schiff base with sodium azide in ethanol compounds (H7-H11) and characterization by using spectroscopic techniques Uv/Vis, FT-IR, C.H.N. and H1-NMR of some the prepared compounds using DMSO-d6 a solvent, in addition melting point and determination a purity of TLC, and this work consists a study of biological activity for the some prepared compounds against four types of pathogenic bacteria and know to be resistant to anti biotic.

scholarly journals Ultrafast Exciton Dynamics in Two Dimensional Covalent Organic Frameworks Reveals Size Dependence to Exciton Diffusion

2020 ◽  
Author(s):  
Nathan C. Flanders ◽  
Matthew S. Kirschner ◽  
Pyosang Kim ◽  
Thomas Fauvell ◽  
Austin Evans ◽  
...  
Keyword(s):  
High Performance ◽  
Transient Absorption ◽  
Domain Size ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Exciton Dynamics ◽  
Singlet Exciton ◽  
Exciton Diffusion ◽  
Absorption Studies ◽  
Exciton Annihilation

<p>Large singlet exciton diffusion lengths are a hallmark of high performance in organic based devices such as photovoltaics, chemical sensors, and photodetectors. In this study, exciton dynamics of a two-dimensional covalent organic framework, COF- 5, is investigated using ultrafast spectroscopic techniques. Following photoexcitation, the COF-5 exciton decays via three pathways: 1) excimer formation (4 ± 2 ps), 2) excimer relaxation (160 ± 40 ps), and 3) excimer decay (>3 ns). Excitation fluence-dependent transient absorption studies suggest that COF-5 has a relatively large diffusion coefficient (0.08 cm2/s). Furthermore, exciton-exciton annihilation processes are characterized as a function of COF-5 crystallite domain size in four different samples, which reveal domain- size dependent exciton diffusion kinetics. These results reveal that exciton diffusion in COF-5 is constrained by its crystalline domain size. These insights indicate the outstanding promise of delocalized excitonic processes available in 2D COFs, which motivate their continued design and implementation into optoelectronic devices. </p>

Assignment of the1H- and13C-NMR spectra of congested helicenes using two-dimensional NMR methods: Phenanthro[3′,4′:3,4]phenanthro[2,1-b]thiophene

1986 ◽  
Vol 23 (5) ◽  
pp. 1587-1593 ◽  
Author(s):  
Andrew S. Zektzer ◽  
John G. Stuart ◽  
Gary E. Martin ◽  
Raymond N. Castle
Keyword(s):  
Nmr Spectra ◽  
Two Dimensional ◽  
Nmr Methods
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