scholarly journals Gold-Catalyzed Highly Regioselective Oxidation of C−C Triple Bonds without Acid Additives: Propargyl Moieties as Masked α,β-Unsaturated Carbonyls

2010 ◽  
Vol 132 (40) ◽  
pp. 14070-14072 ◽  
Author(s):  
Biao Lu ◽  
Chaoqun Li ◽  
Liming Zhang
Keyword(s):  
Triple Bonds ◽  
Unsaturated Carbonyls ◽  
Regioselective Oxidation

A Short Synthesis of the Plant Alkaloid 4-Methyl-2,6-naphthyridine

2019 ◽  
Vol 16 (12) ◽  
pp. 931-934 ◽  
Author(s):  
Alexandra Kamlah ◽  
Franz Bracher
Keyword(s):  
Pyridine Ring ◽  
Cross Coupling ◽  
Antirrhinum Majus ◽  
New Synthesis ◽  
Short Synthesis ◽  
Regioselective Oxidation ◽  
Key Steps

: A new synthesis of the 2,6-naphthyridine alkaloid 4-methyl-2,6-naphthyridine from Antirrhinum majus has been developed. Key steps are a regioselective oxidation of 3-bromo-4,5- dimethylpyridine to the corresponding 4-formyl derivative, and the annulation of the second pyridine ring by Suzuki-Miyaura cross-coupling using (E)-2-ethoxyvinylboronic acid pinacol ester as a masked acetaldehyde equivalent. This protocol gives the alkaloid in four steps starting from commercially available 3,4-dimethylpyridine in 15% overall yield. This annulation protocol should be useful for the synthesis of other condensed pyridines as well.

scholarly journals Gas-phase reactivity of acyclic α,β-unsaturated carbonyls towards ozone

2021 ◽  
Vol 23 (5) ◽  
pp. 3455-3466
Author(s):  
Jan Niklas Illmann ◽  
Iulia Patroescu-Klotz ◽  
Peter Wiesen
Keyword(s):  
Gas Phase ◽  
Unsaturated Carbonyls

This work evaluates different approaches to discuss the reactivity of α,β-unsaturated carbonyls towards ozone comparative to alkene analogues.

scholarly journals Predicting the new carbon nanocages, fullerynes: a DFT study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Qasemnazhand ◽  
Farhad Khoeini ◽  
Farah Marsusi
Keyword(s):  
Density Functional Theory ◽  
Lithium Ion Batteries ◽  
Density Functional ◽  
Lithium Ion ◽  
The Other ◽  
Electron Affinities ◽  
Chemical Formula ◽  
Functional Theory ◽  
Triple Bonds ◽  
Structural And Electronic Properties

AbstractIn this study, based on density functional theory, we propose a new branch of pseudo-fullerenes which contain triple bonds with sp hybridization. We call these new nanostructures fullerynes, according to IUPAC. We present four samples with the chemical formula of C4nHn, and the structures derived from fulleranes. We compare the structural and electronic properties of these structures with those of two common fullerenes and fulleranes systems. The calculated electron affinities of the sampled fullerynes are negative, and much smaller than those of fullerenes, so they should be chemically more stable than fullerenes. Although fulleranes also exhibit higher chemical stability than fullerynes, but pentagon or hexagon of the fullerane structures cannot pass ions and molecules. Applications of fullerynes can be included in the storage of ions and gases at the nanoscale. On the other hand, they can also be used as cathode/anode electrodes in lithium-ion batteries.

scholarly journals First total synthesis of the (±)-2-methoxy-6-heptadecynoic acid and related 2-methoxylated analogs as effective inhibitors of the Leishmania topoisomerase IB enzyme

2012 ◽  
Vol 84 (9) ◽  
pp. 1867-1875 ◽  
Author(s):  
Néstor M. Carballeira ◽  
Michelle Cartagena ◽  
Fengyu Li ◽  
Zhongfang Chen ◽  
Christopher F. Prada ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Total Synthesis ◽  
Leishmania Donovani ◽  
Dna Topoisomerase ◽  
Triple Bonds ◽  
Weak Intermolecular Interactions ◽  
Topoisomerase Ib ◽  
Effective Inhibition ◽  
Acetylenic Fatty Acid

The fatty acids (±)-2-methoxy-6Z-heptadecenoic acid, (±)-2-methoxy-6-hepta-decynoic acid, and (±)-2-methoxyheptadecanoic acid were synthesized and their inhibitory activity against the Leishmania DNA topoisomerase IB enzyme (LdTopIB) determined. Both 2-OMe-17:1 fatty acids were synthesized from 4-bromo-1-pentanol, the olefinic fatty acid in 10 steps and in 7 % overall yield, while the acetylenic fatty acid in 7 steps and in 14 % overall yield. The 2-OMe-17:0 acid was prepared in 6 steps and in 42 % yield from 1-hexa-decanol. The 2-OMe-17:1 acids inhibited LdTopIB, with the acetylenic acid displaying an EC50 = 16.6 ± 1.1 μM, but the 2-OMe-17:0 acid did not inhibit LdTopIB. The (±)-2-methoxy-6Z-heptadecenoic acid preferentially inhibited LdTopIB over the human TopIB enzyme. Unsaturation seems to be a prerequisite for effective inhibition, rationalized in terms of weak intermolecular interactions between the active site of LdTopIB and either the double or triple bonds of the fatty acids. Toxicity toward Leishmania donovani promastigotes was also investigated, resulting in the order acetylenic > olefinic > saturated with the (±)-2-methoxy-6-heptadecynoic acid displaying an EC50 = 74.0 ± 17.1 μM. Our results indicate that α-methoxylation decreases the toxicity of C17:1 fatty acids toward L. donovani promastigotes, but improves their selectivity index.

Molecular orbital and spectroscopic studies of triple bonds between transition-metal atoms. 2. The d5-d5 Re2Cl4(PR3)4 compounds

1983 ◽  
Vol 105 (9) ◽  
pp. 2606-2611 ◽  
Author(s):  
Bruce E. Bursten ◽  
F. Albert Cotton ◽  
Phillip E. Fanwick ◽  
George G. Stanley ◽  
Richard A. Walton
Keyword(s):  
Transition Metal ◽  
Molecular Orbital ◽  
Spectroscopic Studies ◽  
Triple Bonds ◽  
Metal Atoms ◽  
Transition Metal Atoms
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