scholarly journals A New Monoterpene Isolated from Nigella sativa Essential Oil

2017 ◽  
Vol 12 (6) ◽  
pp. 1934578X1701200
Author(s):  
Ahmed Benharref ◽  
Rabia Fdil ◽  
Fadwa El Hanbali ◽  
Abdellah Zeroual ◽  
Mohamed Dakir ◽  
...  
Keyword(s):  
Essential Oil ◽  
Nigella Sativa ◽  
2D Nmr ◽  
Nmr Studies

A new monoterpene 2-allyl-1,4-dihydroxy-5-methylbenzene 1 has been isolated from the essential oil of Nigella sativa seeds along with five known compounds including thymoquinone, carvacrol, dihydrothymoquinone, terpinen-4-ol and dithymoquinone. The structure of the new monoterpene 1 was elucidated using 1D and 2D NMR studies.

2D NMR studies on muscle and cerebral metabolism in vivo

1994 ◽  
Vol 91 ◽  
pp. 697-703 ◽  
Author(s):  
B Gillet ◽  
BT Doan ◽  
C Verre-Sebrie ◽  
O Fedeli ◽  
JC Beloeil ◽  
...  
Keyword(s):  
Cerebral Metabolism ◽  
2D Nmr ◽  
Nmr Studies

scholarly journals Synthesis and Physicochemical Properties of [(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-thiophen-5-yl-substituted Tetrapyrazinoporphyrazine with Magnesium(II) Ion

2021 ◽  
Vol 11 (6) ◽  
pp. 2576
Author(s):  
Sebastian Lijewski ◽  
Jiří Tydlitát ◽  
Beata Czarczynska-Goslinska ◽  
Milan Klikar ◽  
Jadwiga Mielcarek ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
2D Nmr ◽  
Nmr Studies ◽  
Oxygen Formation ◽  
Nmr Techniques ◽  
Flash Column Chromatography ◽  
Photochemical Stability ◽  
Singlet Oxygen Formation ◽  
Very High

Tetrapyrazinoporphyrazine with peripheral menthol-thiophenyl substituents was synthesized using Linstead conditions and purified by flash column chromatography. The optimized synthetic and purification procedures allowed us to obtain a new macrocycle with 36% yield. Tetrapyrazinoporphyrazine derivative was characterized by UV–Vis and NMR spectroscopy, as well as MS spectrometry. Complex NMR studies using 1D and 2D NMR techniques allowed the analysis of the bulky menthol-thiophenyl substituted periphery of the new macrocycle. Further, photochemical stability and singlet oxygen quantum yield were determined by indirect method with diphenylisobenzofuran. The new tetrapyrazinoporphyrazine revealed low generation of singlet oxygen with a quantum yield of singlet oxygen formation at 2.3% in dimethylformamide. In turn, the macrocycle under irradiation with visible light presented very high stability with quantum yield for photostability of 9.59 × 10−6 in dimethylformamide, which figures significantly exceed the border for its classification as a stable porphyrinoid (10−4–10−5).

Two-dimensional NMR studies of acrylate copolymers

2009 ◽  
Vol 81 (3) ◽  
pp. 389-415 ◽  
Author(s):  
A. S. Brar ◽  
Ashok Kumar Goyal ◽  
Sunita Hooda
Keyword(s):  
Methyl Methacrylate ◽  
Methyl Acrylate ◽  
Quantum Coherence ◽  
Multiple Bond ◽  
Microstructural Analysis ◽  
2D Nmr ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Poly Methyl Methacrylate ◽  
Nmr Study

High-resolution NMR spectroscopy is the most versatile, reliable, and generally acceptable technique for the determination of the microstructure of polymers. 2D NMR techniques, along with 1D NMR, have more potential to study absolute configurational assignments and sequence distribution of copolymers. Physical and chemical properties of polymers are influenced fundamentally by their microstructure. We discuss the detailed microstructure analysis of a large number of homopolymers, copolymers, and terpolymers. 2D NMR study of poly(methyl methacrylate) (PMMA), poly(methyl acrylate) (PMA), and poly(methacrylonitrile) (PMAN) is discussed in this article. In addition to homopolymers, 2D heteronuclear single-quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple-bond correlation (HMBC) study of different copolymers such as poly(methyl methacrylate-co-methyl acrylate), poly(styrene-co-methyl methacrylate), and poly(methyl methacrylate-co-methacrylonitrile) have also been reported here. This in turn helps in microstructural analysis of terpolymers such as poly(methacrylonitrile-co-styrene-co-methyl methacrylate), poly(acrylonitrile-co-methyl methacrylate-co-methyl acrylate), and poly(ethylene-co-vinyl acetate-co-carbon monoxide).

The6Li,6Li-INADEQUATE Experiment: A New Tool for 1D- and 2D-NMR Studies of Organolithium Compounds

1992 ◽  
Vol 75 (3) ◽  
pp. 883-891 ◽  
Author(s):  
Oswald Eppers ◽  
Thomas Fox ◽  
Harald Günther
Keyword(s):  
2D Nmr ◽  
Nmr Studies ◽  
Organolithium Compounds

scholarly journals Two Ring-A-Aromatized Bile Acids from the Marine Sponge Sollasella Moretonensis

2010 ◽  
Vol 5 (10) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Zhenyu Lu ◽  
Ryan M. Van Wagoner ◽  
Mary Kay Harper ◽  
John N. A. Hooper ◽  
Chris M. Ireland
Keyword(s):  
Bile Acids ◽  
Marine Sponge ◽  
2D Nmr ◽  
Natural Source ◽  
Nmr Studies

Two ring-A-aromatized bile acids, 1 and 2, were isolated from the sponge Sollasella moretonensis, collected from the seabed of northern Queensland. Structures were assigned on the basis of extensive 1D and 2D NMR studies, as well as analysis by HRESIMS. Compound 2 has previously been produced synthetically, though this marks its first isolation from a natural source.

scholarly journals Two Distinct Essential Oil Bearing Races of Tanacetum nubigenum Wallich ex DC from Kumaon Himalaya

2007 ◽  
Vol 2 (7) ◽  
pp. 1934578X0700200 ◽  
Author(s):  
Chandan S. Chanotiya ◽  
Chandra S. Mathela
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Plant Material ◽  
2D Nmr ◽  
Bornyl Acetate ◽  
2D Nmr Spectroscopy ◽  
Aerial Parts ◽  
Kumaon Himalaya ◽  
Linalool Oxide ◽  
Total Oil

The essential oil from the aerial parts of Tanacetum nubigenum Wallich ex DC collected from the Milam glacier moraine showed the presence of 73 compounds, of which 69, representing 87.9% of the total oil, have been identified, with bornyl acetate (39.7%), borneol (10.6%), ( E)-β-farnesene (6.6%) and 1,8-cineole (5.8%) as major constituents, while the oil from the plant material from the Pindari glacier area contained a total of 81 compounds, of which 77 have been identified. This oil was characterized by the presence of (3 R, 6 R)-linalool oxide acetate (69.4%), β-eudesmol (3.2%), selin-11-en-4α-ol (3.2%) and (3.2% and 1.2%, respectively) for compounds ( E) and ( Z)-2-(2,4-hexadiynylidene)-1,6-dioxospiro [4,4] non-3-ene, respectively. The major constituents of the essential oils from the aerial parts were separated and characterized by GC, GC/MS and 1D- and 2D-NMR spectroscopy. The chemical differences between the two essential oils place them as distinct chemical races or chemotypes.

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