scholarly journals Studies on polynuclear furoquinones. Part 1: Synthesis of tri- and tetra-cyclic furoquinones simulating BCD/ABCD ring system of furoquinone diterpenoids

2009 ◽  
Vol 5 ◽  
Author(s):  
Faruk Hasan Shaik ◽  
Gandhi Kumar Kar
Keyword(s):  
Acid Derivative ◽  
Boronic Acid ◽  
Functional Group ◽  
Suzuki Coupling ◽  
Ring System ◽  
Core Nucleus ◽  
Tanshinone I ◽  
The Core ◽  
Acetic Ester ◽  
Naphthyl Acetate

Synthesis of phenanthro[1,2-b]furan-10,11-dione, the core nucleus present in Tanshinone-I is described in 8–10 steps starting from 2-bromo-3,4-dihydro-1-naphthaldehyde. The bromoaldehyde was converted to methyl 2-(2-bromo-1-naphthyl)acetate or 2-(2-bromo-1-naphthyl)acetonitrile following the protocol of functional group transformations. Subsequent Suzuki coupling of this ester/nitrile derivative with furan-2-boronic acid produced [2-(2-furyl)-1-naphthyl]acetic ester/nitrile which on hydrolysis furnished the corresponding acid derivative. Cyclization of the acid followed by oxidation of the phenol, with Fremy’s salt, produced the tetra-cyclic furoquinone, phenanthro[1,2-b]furan-10,11-dione. This method has also been extended for the synthesis of the tricyclic furoquinone, naphtho[1,2-b]furan-4,5-dione.

scholarly journals 2-{3,5-Bis-[5-(3,4-didodecyloxyphenyl)thien-2-yl]phenyl}-5-(3,4-didodecyloxyphenyl)thiophene

Molbank ◽  
10.3390/m1225 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1225
Author(s):  
Matthias Jochem ◽  
Heiner Detert
Keyword(s):  
Liquid Crystal ◽  
Optical Microscopy ◽  
Boronic Acid ◽  
Suzuki Coupling ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
The Core ◽  
Discotic Liquid Crystal ◽  
Acid Catalyzed

Star-shaped compounds are widely recognized as emerging materials for optical and electrical applications and as scaffolds of discotic liquid crystal. While the C3-symmetrical tri(phenylthienyl)benzene is the core for several electroopotical materials, no liquid crystal with this scaffold has yet been reported. Acid-catalyzed cyclocondensation of bromoacetylthiophene gives a C3-symmetrical star, threefold Suzuki coupling results in extension of the conjugated system. With 3,4-didodecylocyphenyl boronic acid, a star with a large rigid conjugated system and flexible aliphatic periphery is obtained. Differentials scanning calorimetry and polarized optical microscopy reveal an enantiotropic mesophase from 66 °C to 106 °C.

scholarly journals Synthesis of cis-hydrindan-2,4-diones bearing an all-carbon quaternary center by a Danheiser annulation

2018 ◽  
Vol 14 ◽  
pp. 2597-2601 ◽  
Author(s):  
Gisela V Saborit ◽  
Carlos Cativiela ◽  
Ana I Jiménez ◽  
Josep Bonjoch ◽  
Ben Bradshaw
Keyword(s):  
Building Blocks ◽  
Ring System ◽  
Core Nucleus ◽  
Keto Ester ◽  
The Core ◽  
Quaternary Center

A straightforward synthetic entry to functionalized hydrindane compounds based on a rapid assembly of the core nucleus by a Danheiser cycloaddition is reported. Valuable bicyclic building blocks containing the fused five and six-membered carbocyclic ring system can be achieved in only four steps from a simple acyclic β-keto ester.

Tele-Substitution Reactions in the Synthesis of a Promising Class of Antimalarials

2020 ◽  
Author(s):  
Marat Korsik ◽  
Edwin Tse ◽  
David Smith ◽  
William Lewis ◽  
Peter J. Rutledge ◽  
...  
Keyword(s):  
Heterocyclic Ring ◽  
Ring System ◽  
Substitution Reactions ◽  
Laboratory Notebook ◽  
Polar Solvents ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Core ◽  
Nmr Data

<p></p><p>We have discovered and studied a <i>tele</i>substitution reaction in a biologically important heterocyclic ring system. Conditions that favour the <i>tele</i>-substitution pathway were identified: the use of increased equivalents of the nucleophile or decreased equivalents of base, or the use of softer nucleophiles, less polar solvents and larger halogens on the electrophile. Using results from X-ray crystallography and isotope labelling experiments a mechanism for this unusual transformation is proposed. We focused on this triazolopyrazine as it is the core structure of the <i>in vivo </i>active anti-plasmodium compounds of Series 4 of the Open Source Malaria consortium.</p> <p> </p> <p>Archive of the electronic laboratory notebook with the description of all conducted experiments and raw NMR data could be accessed via following link <a href="https://ses.library.usyd.edu.au/handle/2123/21890">https://ses.library.usyd.edu.au/handle/2123/21890</a> . For navigation between entries of laboratory notebook please use file "Strings for compounds in the article.pdf" that works as a reference between article codes and notebook codes, also this file contain SMILES for these compounds. </p><br><p></p>

scholarly journals Short, enantioselective, gram-scale synthesis of (−)-zephyranthine

2021 ◽  
Author(s):  
Yuxiang Zhao ◽  
Yanren Zhu ◽  
Guolan Ma ◽  
Qi Wei ◽  
Shaoxiong Yang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Functional Group ◽  
Ring System ◽  
System Construction ◽  
Synthesis Design

A reasonable synthesis design by strategically integrating functional group manipulation into the ring system construction resulted in a short, enantioselective, gram-scale total synthesis of (−)-zephyranthine.

scholarly journals Tuning the sensitivity towards mercury via cooperative binding to d-fructose: dual fluorescent chemosensor based on 1,8-naphthyridine-boronic acid derivative

RSC Advances ◽  
2021 ◽  
Vol 11 (24) ◽  
pp. 14862-14870
Author(s):  
Marina Rajadurai ◽  
E. Ramanjaneya Reddy
Keyword(s):  
Metal Ions ◽  
Acid Derivative ◽  
Boronic Acid ◽  
Toxic Metal ◽  
Fluorescent Chemosensor ◽  
Cooperative Binding ◽  
Toxic Metal Ions

This new dual d-fructose–mercury chemosensor is the first example of utilizing boronic acid–diol complexation for enhancement of the sensor's sensitivity towards toxic metal ions.

scholarly journals Inhibition of pancreatic lipase in vitro by the covalent inhibitor tetrahydrolipstatin

1988 ◽  
Vol 256 (2) ◽  
pp. 357-361 ◽  
Author(s):  
P Hadváry ◽  
H Lengsfeld ◽  
H Wolfer
Keyword(s):  
Transition State ◽  
Acid Derivative ◽  
Pancreatic Lipase ◽  
Active Site ◽  
Boronic Acid ◽  
Selective Inhibitor ◽  
Covalent Intermediate ◽  
State Form ◽  
Covalent Inhibitor

Tetrahydrolipstatin inhibits pancreatic lipase from several species, including man, with comparable potency. The lipase is progressively inactivated through the formation of a long-lived covalent intermediate, probably with a 1:1 stoichiometry. The lipase substrate triolein and also a boronic acid derivative, which is presumed to be a transition-state-form inhibitor, retard the rate of inactivation. Therefore, in all probability, tetrahydrolipstatin reacts with pancreatic lipase at, or near, the substrate binding or active site. Tetrahydrolipstatin is a selective inhibitor of lipase; other hydrolases tested were at least a thousand times less potently inhibited.

scholarly journals Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp2)–H activation and C(sp3)–H amination

2019 ◽  
Vol 15 ◽  
pp. 571-576 ◽  
Author(s):  
Liangliang Song ◽  
Guilong Tian ◽  
Johan Van der Eycken ◽  
Erik V Van der Eycken
Keyword(s):  
Natural Products ◽  
Functional Group ◽  
The Core

A rhodium(III)-catalyzed intramolecular oxidative annulation of O-substituted N-hydroxyacrylamides for the construction of indolizinones via sequential C(sp2)–H activation and C(sp3)–H amination has been developed. This approach shows excellent functional-group tolerance. The synthesized scaffold forms the core of many natural products with pharmacological relevance.

Suzuki-Coupling of Cp*Ru(para-C6H4Br2) with Phenyl Boronic Acid: A Model Reaction for the Synthesis of Organometallic Polymers

1996 ◽  
Vol 129 (11) ◽  
pp. 1323-1325 ◽  
Author(s):  
Kathrin Harre ◽  
Volker Enkelmann ◽  
Margit Schulze ◽  
Uwe H. F. Bunz
Keyword(s):  
Boronic Acid ◽  
Suzuki Coupling ◽  
Model Reaction ◽  
Organometallic Polymers ◽  
Phenyl Boronic Acid
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