Application of Azide-Tetrazole Tautomerism and Arylsulfanyl Group Dance in the Synthesis of Thiosubstituted Tetrazoloquinazolines

Synthesis ◽  
2020 ◽  
Author(s):  
Irina Novosjolova ◽  
Māris Turks ◽  
Andris Jeminejs ◽  
Svetlana M. Goliškina ◽  
Dmitrijs Stepanovs ◽  
...  
Keyword(s):  
Substitution Reaction ◽  
Tautomeric Equilibrium ◽  
The Other ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
X Ray ◽  
X Ray Crystallography ◽  
Other Hand

AbstractNucleophilic aromatic substitution reaction between 4-aryl­thio-2-chloroquinazolines and NaN3 takes place with an unusual sulfanyl group dance and leads to the formation of 5-(arylthio)tetrazolo[1,5-c]-quinazolines, which do not form the azide tautomer and do not undergo CuAAC reactions with alkynes. On the other hand, 5-azidotetrazolo[1,5-a]quinazoline (formally described as 2,4-diazidoquinazoline) undergoes regioselective nucleophilic aromatic substitution with thiols at C5 and forms 5-(alkyl/arylthio)tetrazolo[1,5-a]quinazolines, the structure of which has been proved by X-ray crystallography. The latter exist in tautomeric equilibrium with their 2-azidoquinazoline form, which provides possibility for copper-catalyzed azide–alkyne 1,3-dipolar cyclo­addition reaction, leading to the 4-alkyl/arylthio-2-(1H-1,2,3-triazol-1-yl)quinazolines.

An Expedient Synthesis of Ketocalix[6]arene Hexamethyl Ether

Synthesis ◽  
2018 ◽  
Vol 50 (19) ◽  
pp. 3897-3901 ◽  
Author(s):  
Silvio Biali ◽  
Norbert Itzhak
Keyword(s):  
Substitution Reaction ◽  
Dimethyl Sulfide ◽  
Nucleophilic Aromatic Substitution ◽  
Water Mixture ◽  
Aromatic Substitution ◽  
Arene Derivative ◽  
X Ray ◽  
X Ray Crystallography ◽  
One Step ◽  
Boron Tribromide

p-tert-Butylcalix[6]arene hexamethyl ether was oxidized in one step to the corresponding ketocalix[6]arene via photochemical bromination (100 W spot lamp) with NBS in a chloroform/water mixture. A pentamethyl ketocalix[6]arene derivative was obtained by reaction of the ketocalix[6]arene hexamethyl ether with boron tribromide dimethyl sulfide complex, and characterized by X-ray crystallography. In the presence of base, the compound undergoes an intramolecular nucleophilic aromatic substitution reaction.

Facile 1,1-Carboboration Reaction of a Diarylphosphino-substituted Conjugated Diyne with Tris(pentafluorophenyl)borane

2013 ◽  
Vol 68 (5-6) ◽  
pp. 666-674 ◽  
Author(s):  
Philipp Feldhaus ◽  
Gerald Kehr ◽  
Roland Fröhlich ◽  
Constantin G. Daniliuc ◽  
Gerhard Erker
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
X Ray ◽  
Frustrated Lewis Pair ◽  
Selective Formation

Bis(dimesitylphosphanyl)butadiyne (14) reacts with B(C6F5)3 by a 1,1-carboboration sequence. The selective attack at a single phosphanyl-alkyne moiety is observed. First a phosphirenium-borate zwitterion 15 is formed at r. t. Thermolysis (80 °C) results in the E-selective formation of the 1,1- carboboration product, the frustrated Lewis pair (FLP) E-16, which upon heating to 160 °C eventually undergoes isomerization followed by an internal nucleophilic aromatic substitution reaction to give the product 17 featuring a -B(F)(C6F5)2 substituent at the five-membered P-heterocycle. Finally, the FLP E-16 was reacted with n-butylisocyanide to yield the five-membered heterocyclic product 18, formed by P,B addition to the isonitrile carbon atom. Compounds 14, 15, 17, and 18 were characterized by X-ray crystal structure analyses

Enantioselective Nucleophilic Aromatic Substitution Reaction of Azlactones to Synthesize Quaternary α-Amino Acid Derivatives

Synlett ◽  
2020 ◽  
Author(s):  
Xiaohua Liu ◽  
Yi Li ◽  
Hao Pan ◽  
Wang-Yuren Li ◽  
Xiaoming Feng
Keyword(s):  
Hydrogen Bonding ◽  
Charge Transfer ◽  
Amino Acid ◽  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Amino Acid Derivatives ◽  
Amino Acid Esters ◽  
Aromatic Substitution ◽  
Charge Transfer Interaction ◽  
Acid Esters

AbstractAn asymmetric organocatalytic nucleophilic aromatic substitution reaction of azlactones with electron-deficient aryls was established. A variety of α-aryl α-alkyl α-amino acid esters and peptides were obtained in decent yields and stereoselectivities. A new bifunctional catalytic mode involving charge-transfer interaction and hydrogen bonding is proposed to explain the enantioselectivity.

scholarly journals White Dwarf Masses and Accretion Rates of Recurrent Novae: an X-ray Perspective

2011 ◽  
Vol 7 (S281) ◽  
pp. 186-189
Author(s):  
Koji Mukai ◽  
Jennifer L. Sokoloski ◽  
Thomas Nelson ◽  
Gerardo J. M. Luna
Keyword(s):  
White Dwarf ◽  
Cataclysmic Variables ◽  
The Other ◽  
X Ray ◽  
Other Hand ◽  
Accretion Rates

AbstractWe present recent results of quiescent X-ray observations of recurrent novae (RNe) and related objects. Several RNe are luminous hard X-ray sources in quiescence, consistent with accretion onto a near Chandrasekhar mass white dwarf. Detection of similar hard X-ray emissions in old novae and other cataclysmic variables may lead to identification of additional RNe candidates. On the other hand, other RNe are found to be comparatively hard X-ray faint. We present several scenarios that may explain this dichotomy, which should be explored further.

New Highly Stable Metallabenzenes via Nucleophilic Aromatic Substitution Reaction

2011 ◽  
Vol 17 (15) ◽  
pp. 4223-4231 ◽  
Author(s):  
Ran Lin ◽  
Hong Zhang ◽  
Shunhua Li ◽  
Jiani Wang ◽  
Haiping Xia
Keyword(s):  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution

Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photophysical properties

2021 ◽  
Vol 77 (3) ◽  
pp. 137-143
Author(s):  
Ismail Fidan ◽  
Emel Onal ◽  
Catherine Hirel
Keyword(s):  
Magnetic Measurements ◽  
Photophysical Properties ◽  
Nucleophilic Aromatic Substitution ◽  
Structural Studies ◽  
Aromatic Substitution ◽  
Nitronyl Nitroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ft Ir

The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwave-assisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT–IR, MALDI–TOF MS, elemental analysis, UV–Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C—H...X and C—X...π (X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals.

Synthesis of ZrO2 Nanotubes by Anodization of Zr Foil

2015 ◽  
Vol 799-800 ◽  
pp. 125-129
Author(s):  
Mary Donnabelle L. Balela ◽  
April Alexa S. Lagarde ◽  
Stephen Jann A. Tamayo ◽  
Nikko S. Villareal ◽  
Ann Marielle Parreno
Keyword(s):  
Aqueous Solution ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Preparation ◽  
The Other ◽  
Preparation Methods ◽  
X Ray ◽  
Anodization Time ◽  
Other Hand ◽  
Scanning Electron

Zirconia (ZrO2) nanotubes were synthesized by anodization of zirconium (Zr) foil in NH4Fand (NH4)2SO4 aqueous solution. Different surface preparation methods (electropolishing and etching) were applied on the Zr foil prior to anodizaton. In addition, the anodization time and NH4F concentration were varied. The structure and morphologies of the nanotubes and their crystallinity were confirmed using scanning electron microscope and x-ray diffractometer, respectively. ZrO2 nanotubes with large diameters and thick walls were formed at lower NH4F concentration and longer anodization time. On the other hand, smaller nanotubes with thinner walls were produced when the NH4F concentration was increased. The synthesized nanotubes were predominantly tetragonal ZrO2 with small amounts of monoclinic ZrO2.

Portrayal of the Color Polymorphism in the 5-Acetyl-derivative of ROY

CrystEngComm ◽  
2022 ◽  
Author(s):  
Bernardo Albuquerque Nogueira ◽  
Maria Carvalho ◽  
José António Paixão ◽  
M. Ermelinda S. Eusébio ◽  
Susana M. M. Lopes ◽  
...  
Keyword(s):  
Substitution Reaction ◽  
Acetyl Derivative ◽  
Color Polymorphism ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution

A novel derivative of the prominent ROY compound, 5-acetyl-2-((2-nitrophenyl)amino)thiophene-3-carbonitrile (AcROY), was synthesized in a two-steps procedure by the nucleophilic aromatic substitution reaction between 1-fluoro-2-nitrobenzene and 2-aminothiophene-3-carbonitrile, followed by Friedel–Crafts acylation...

The Versatility of the Aryne–Imine–Aryne Coupling for the ­Synthesis of Acridinium Photocatalysts

Synlett ◽  
2021 ◽  
Author(s):  
Christof Sparr ◽  
Valeriia Hutskalova
Keyword(s):  
Substitution Reaction ◽  
Precious Metal ◽  
Photophysical Properties ◽  
Cation Radical ◽  
Coupling Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
The Novel ◽  
Aromatic Substitution ◽  
Efficient Synthesis

AbstractThe increasing use of acridinium photocatalysts as sustainable alternative to precious metal-based counterparts encourages the design and efficient synthesis of distinct catalyst structures. Herein, we report our exploration of the scope of the aryne–imine–aryne coupling reaction combined with a subsequent acridane oxidation for a short two-step approach towards various acridinium salts. The photophysical properties of the novel photocatalysts were investigated and the practical value was demonstrated by a cation-radical accelerated nucleophilic aromatic substitution reaction.

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