scholarly journals Synthesis of the B-seco limonoid core scaffold

2014 ◽  
Vol 10 ◽  
pp. 194-208 ◽  
Author(s):  
Hanna Bruss ◽  
Hannah Schuster ◽  
Rémi Martinez ◽  
Markus Kaiser ◽  
Andrey P Antonchick ◽  
...  
Keyword(s):  
Natural Products ◽  
Claisen Rearrangement ◽  
Sigmatropic Rearrangement ◽  
Detailed Model ◽  
Model Studies ◽  
Sterically Demanding

Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland–Claisen rearrangement can be employed to construct the central C9–C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems.

Potential for Treatment of Neurodegenerative Diseases with Natural Products or Synthetic Compounds that Stabilize Microtubules

2020 ◽  
Vol 26 (35) ◽  
pp. 4362-4372
Author(s):  
John H. Miller ◽  
Viswanath Das
Keyword(s):  
Natural Products ◽  
Neurodegenerative Diseases ◽  
In Vivo Models ◽  
Synthetic Compounds ◽  
Stabilizing Agents ◽  
Animal Models Of Disease ◽  
Model Studies ◽  
Models Of Disease

No effective therapeutics to treat neurodegenerative diseases exist, despite significant attempts to find drugs that can reduce or rescue the debilitating symptoms of tauopathies such as Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis, or Pick’s disease. A number of in vitro and in vivo models exist for studying neurodegenerative diseases, including cell models employing induced-pluripotent stem cells, cerebral organoids, and animal models of disease. Recent research has focused on microtubulestabilizing agents, either natural products or synthetic compounds that can prevent the axonal destruction caused by tau protein pathologies. Although promising results have come from animal model studies using brainpenetrant natural product microtubule-stabilizing agents, such as paclitaxel analogs that can access the brain, epothilones B and D, and other synthetic compounds such as davunetide or the triazolopyrimidines, early clinical trials in humans have been disappointing. This review aims to summarize the research that has been carried out in this area and discuss the potential for the future development of an effective microtubule stabilizing drug to treat neurodegenerative disease.

Experiments directed towards the synthesis of anthracyclinones. VII. Model studies with allyl naphthalenyl ethers

1983 ◽  
Vol 36 (4) ◽  
pp. 803 ◽  
Author(s):  
IK Boddy ◽  
RC Cambie ◽  
G Dixon ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Claisen Rearrangement ◽  
Side Chain ◽  
Model Studies ◽  
Chain Isomerization

The Claisen rearrangement of some allyl naphthalen-1-yl ethers has been examined, together with methods for modification of the resulting 2-ally1 side chain. Isomerization of the C-allyl substituent to a prop-1-enyl group followed by ozonolysis gives a formyl derivative, while ozonolysis of a 2-(2-methylprop-2-enyl) moiety or mercuriation of a 2-(2-chloroprop-2-enyl) substituent leads to an acetonyl derivative. Treatment of phenols with iodine(I) acetate and an excess of silver(I) acetate gives 4-hydroxyaryl acetates, probably via dienone intermediates.

The Claisen rearrangement in the syntheses of bioactive natural products

Tetrahedron ◽  
2013 ◽  
Vol 69 (34) ◽  
pp. 6921-6957 ◽  
Author(s):  
K.C. Majumdar ◽  
Raj Kumar Nandi
Keyword(s):  
Natural Products ◽  
Claisen Rearrangement ◽  
Bioactive Natural Products

Oxidation of substituted aromatic hydrocarbons in the tropospheric aqueous phase: kinetic mechanism development and modelling

2018 ◽  
Vol 20 (16) ◽  
pp. 10960-10977 ◽  
Author(s):  
Erik H. Hoffmann ◽  
Andreas Tilgner ◽  
Ralf Wolke ◽  
Olaf Böge ◽  
Arno Walter ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Aromatic Hydrocarbons ◽  
Aromatic Compounds ◽  
Kinetic Data ◽  
Kinetic Mechanism ◽  
Detailed Model ◽  
Model Studies ◽  
Phase Chemistry

An aqueous-phase chemistry mechanism for the oxidation of aromatic compounds in the atmosphere is developed based on available kinetic data. Detailed model studies successfully describe the oxidation and functionalization of monoaromatic compounds in the atmosphere.

Modelling the Tropospheric Multiphase Chemistry of Biomass Burning Trace Compounds Using the Chemical Aqueous Phase Radical Mechanism (CAPRAM)

2021 ◽  
Author(s):  
Lin He ◽  
Erik Hans Hoffmann ◽  
Andreas Tilgner ◽  
Hartmut Herrmann
Keyword(s):  
Aqueous Phase ◽  
Biomass Burning ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Radical Mechanism ◽  
Aerosol Formation ◽  
Detailed Model ◽  
Model Studies ◽  
Trace Species

<p>Biomass burning (BB) is a significant contributor to air pollution on global, regional and local scale with impacts on air quality, public health and climate. Anhydrosugars (levoglucosan, mannosan and galactocan) and methoxyphenols (guaiacol, creosol, etc.) are important tracer compounds emitted through biomass burning. Once emitted, they can undergo complex multiphase chemistry in the atmosphere contributing to secondary organic aerosol formation. However, their chemical multiphase processing is not yet well understood and investigated by models. Therefore, the present study aimed at a better understanding of the multiphase chemistry of these BB trace species by means of detailed model studies with a new developed detailed chemical CAPRAM biomass burning module (CAPRAM-BB). This module was developed based on the kinetic data from the laser flash photolysis measurements in our lab at TROPOS and other literature studies. The developed CAPRAM-BB module includes 2991 reactions (thereof 9 phase transfers and 2982 aqueous-phase reactions). By coupling with the multiphase chemistry mechanism MCMv3.2/CAPRAM4.0 and the extended CAPRAM aromatics (CAPRAM-AM1.0) and halogen modules (CAPRAM-HM3.0), it is being applied for some residential wood burning cases in Europe and wildfire cases in the US. Our model results show that the BB chemistry could significantly affect the budgets of important atmospheric oxidants such as H<sub>2</sub>O<sub>2</sub> and HONO, and contribute to the SOA formation especially the fraction of brown carbon and substituted organic acids.</p>

Model studies for the stereoselective construction of the BC-ring of armatol F based on Ireland-Claisen rearrangement and relay ring-closing olefin metathesis

2010 ◽  
Vol 51 (34) ◽  
pp. 4543-4546 ◽  
Author(s):  
Kenshu Fujiwara ◽  
Keita Tanaka ◽  
Yasushi Katagiri ◽  
Hidetoshi Kawai ◽  
Takanori Suzuki
Keyword(s):  
Olefin Metathesis ◽  
Claisen Rearrangement ◽  
Model Studies
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