Sulfonyl esters. 2. CS cleavage in some substitution reactions of nitrobenzenesulfonates

1990 ◽  
Vol 68 (8) ◽  
pp. 1450-1455 ◽  
Author(s):  
James Clayton Baum ◽  
Jimat Bolhassan ◽  
Richard Francis Langler ◽  
Paul Joseph Pujol ◽  
Raj Kumar Raheja
Keyword(s):  
Electron Transfer ◽  
Molecular Orbital ◽  
Radical Anion ◽  
Nucleophilic Aromatic Substitution ◽  
Bond Rupture ◽  
Single Electron Transfer ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Nucleophilic Aromatic Substitutions ◽  
Aromatic Sulfonate

An attempt to explore aromatic sulfonate esters as agents for the condensation of alcohols with mercaptans revealed an unusual process for sulfonate esters: CS bond rupture. Two mechanistic possibilities for CS bond rupture are explored: (i) radical anion intermediacy via single electron transfer and (ii) nucleophilic aromatic substitution. Both experiments and molecular orbital computations are presented to support the conclusion that nucleophilic aromatic substitutions are occurring. Keywords: sulfonyl esters, nitrobenzenesulfonates, CS bond rupture.

scholarly journals Evidence of single electron transfer from the enolate anion of an N,N′-dialkyldiketopiperazine additive in BHAS coupling reactions

2017 ◽  
Vol 15 (41) ◽  
pp. 8810-8819 ◽  
Author(s):  
Katie J. Emery ◽  
Tell Tuttle ◽  
John A. Murphy
Keyword(s):  
Electron Transfer ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Coupling Reactions ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Homolytic Aromatic Substitution ◽  
Enolate Anion

A designed N,N′-dialkyldiketopiperazine (DKP) provides evidence for the role of DKP additives as initiators that act by electron transfer in base-induced homolytic aromatic substitution reactions, involving coupling of haloarenes to arenes.

scholarly journals Gas-phase electrophilic aromatic substitution mechanism with strong electrophiles explained by ab initio non-adiabatic dynamics

2014 ◽  
Vol 16 (35) ◽  
pp. 18686-18689 ◽  
Author(s):  
Daniel Kinzel ◽  
Shmuel Zilberg ◽  
Leticia González
Keyword(s):  
Electron Transfer ◽  
Ab Initio ◽  
Gas Phase ◽  
Radical Pair ◽  
Electrophilic Aromatic Substitution ◽  
Single Electron Transfer ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Substitution Mechanism ◽  
Adiabatic Dynamics

Ultrafast single electron transfer producing a radical pair governs the formation of a σ-complex in gas-phase electrophilic aromatic substitution reactions.

scholarly journals The use of bisphthalonitriles in the synthesis of side-strapped 1,11,15,25-tetrasubstituted phthalocyanines

1996 ◽  
Vol 74 (3) ◽  
pp. 307-318 ◽  
Author(s):  
Clifford C. Leznoff ◽  
David M. Drew
Keyword(s):  
Key Words ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Pure Compounds

Nucleophilic aromatic substitution reactions of 3-nitrophthalonitrile yield 3-hydroxyphthalonitrile and 3-neopentoxyphthalonitrile, the latter of which condensed to 1,8,15,22-tetraneopentoxyphthalocyanine as a mixture of isomers. Bisphthalonitriles such as 1,3-bis(2′,3′-dicyanophenoxy)-2,2-dipentylpropane, 1,3-bis(2′,3′-dicyanophenoxy)-2,2-diethylpropane, 1,3-bis(2′,3′-dicyanophenoxy)-2,2-dioctylpropane, and 1,3-bis(2′,3′-dicyanophenoxy)-2-methyl-2-trityloxymethylpropane all gave bis-crown-like 1,11,15,25-tetrasubstituted phthalocyanines as pure compounds when treated with lithium octoxide in 1-octanol at 196 °C. A host of nine other bisphthalonitriles including 1,5-bis(2′,3′-dicyanophenoxy)-3-oxapentane, 1,1-bis(2′,3′-dicyanophenoxymethyl)cyclohexane, 1,2-bis(2′,3′-dicyanophenoxymethyl)benzene, and 2,5-bis(2′,3′-dicyanophenoxymethyl)furan did not dimerize to mononuclear phthalocynaines. The "gem dimethyl" effect was suggested as a reason for the successful macrocyclizations. Key words: nucleophilic aromatic substitution, phthalonitriles, bisphthalonitriles, 1,11,15,25-tetrasubstituted phthalocyanines.

scholarly journals Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

2019 ◽  
Vol 15 ◽  
pp. 474-489 ◽  
Author(s):  
Andrejs Šišuļins ◽  
Jonas Bucevičius ◽  
Yu-Ting Tseng ◽  
Irina Novosjolova ◽  
Kaspars Traskovskis ◽  
...  
Keyword(s):  
Nucleophilic Aromatic Substitution ◽  
Secondary Amines ◽  
Acetonitrile Solution ◽  
Quantum Yields ◽  
Cell Labelling ◽  
Aromatic Substitution ◽  
Fluorescent Properties ◽  
Substitution Reactions ◽  
Low Cytotoxicity ◽  
Electron Donating Groups

The synthesis of novel fluorescent N(9)-alkylated 2-amino-6-triazolylpurine and 7-deazapurine derivatives is described. A new C(2)-regioselectivity in the nucleophilic aromatic substitution reactions of 9-alkylated-2,6-diazidopurines and 7-deazapurines with secondary amines has been disclosed. The obtained intermediates, 9-alkylated-2-amino-6-azido-(7-deaza)purines, were transformed into the title compounds by CuAAC reaction. The designed compounds belong to the push–pull systems and possess promising fluorescence properties with quantum yields in the range from 28% to 60% in acetonitrile solution. Due to electron-withdrawing properties of purine and 7-deazapurine heterocycles, which were additionally extended by triazole moieties, the compounds with electron-donating groups showed intramolecular charge transfer character (ICT/TICT) of the excited states which was proved by solvatochromic dynamics and supported by DFT calculations. In the 7-deazapurine series this led to increased fluorescence quantum yield (74%) in THF solution. The compounds exhibit low cytotoxicity and as such are useful for the cell labelling studies in the future.

Elektronentransfer und Ionenpaare, 15 [ 1– 3] Radikalanion und Radikal-Kontakt-Ionenpaare von Dimesityl-tetraketon / Electron Transfer and Ion Pairing, 15 [1-3] Radical Anion and Radical Ion Pairs of Dimesityl Tetraketone

1990 ◽  
Vol 45 (8) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. Bock ◽  
P. Hänel ◽  
H.-F. Herrmann
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Temperature Dependent ◽  
Contact Ion Pairs

The radical anion of dimesityltetraketone (ERed, I = -0.40 V) is easily generated in THF by potassium mirror/[2.2.2]-cryptand reduction. Its contact ion pairs with Na⊕, Cs⊕ and Ba⊕⊕ counter cations, prepared in THF solution by single electron transfer from the respective metals, are characterized by their ESR/ENDOR spectra, which exhibit temperature-dependent metal couplings of aNa⊕ = 0.061 mT (190 K), aCs⊕ = 0.021 mT (190 K), and aBa⊕⊕ = 0.145 mT (295 K).

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