Nucleophilic substitution of S-phenyl thiol esters by electrogenerated polysulfide ions in N,N-dimethylacetamide

1998 ◽  
pp. 607-610 ◽  
Author(s):  
Abdelkader Ahrika ◽  
Meriem Anouti ◽  
Julie Robert ◽  
Jacky Paris
Keyword(s):  
Nucleophilic Substitution ◽  
Thiol Esters ◽  
Polysulfide Ions

Article

1998 ◽  
Vol 76 (12) ◽  
pp. 1867-1874
Author(s):  
A Ahrika ◽  
M Anouti ◽  
J E Robert ◽  
J L Paris
Keyword(s):  
Nucleophilic Substitution ◽  
Carbonyl Carbon ◽  
Absorption Spectrophotometry ◽  
Thiol Esters ◽  
End Products

S-Aryl thiol esters RC(O)SAr and ArS2- ions are the end products resulting from the reactions between bis(2-nitrophenyl) disulfide Ar2S2 and thiocarboxylate ions RC(O)S- (R = Me, Ph) at 20°C. The apparent SNAr process in fact occurs in two steps as shown by UV-vis absorption spectrophotometry coupled with voltammetry: (i) formation of diacyl disulfides [RC(O)]2S2 and ArS- ions by redox exchange; (ii) subsequent nucleophilic substitution of 2-nitrophenyl thiolate ions at the carbonyl carbon of diacyl disulfides.Key words: diacyl disulfides, 2-nitrophenyldisulfide ions, N,N-dimethylacetamide, nucleophilic substitution, spectroelectrochemistry.

scholarly journals Nucleophilic Substitution of Alkyl Halides by Electrogenerated Polysulfide Ions in N,N-dimethylacetamide.

1999 ◽  
Vol 53 ◽  
pp. 513-520 ◽  
Author(s):  
Abdelkader Ahrika ◽  
Julie Robert ◽  
Meriem Anouti ◽  
Jacky Paris ◽  
Zong-Hui Jiang ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Alkyl Halides ◽  
Polysulfide Ions

The Synthesis of New Selenium-containing Heterocycles by the Oxidation Reaction of 2,4-Diaryltetrahydro-4H-selenochromenes

2020 ◽  
Vol 24 (15) ◽  
pp. 1663-1668
Author(s):  
Dmitriy Yurievich Direnko ◽  
Boris Ivanovich Drevko ◽  
Yaroslav Borisovich Drevko
Keyword(s):  
Nucleophilic Substitution ◽  
Chlorine Atom ◽  
Oxidation Reaction ◽  
Heterocyclic Fragment ◽  
Oxidative Aromatization

We have explored the reactions of tetrahydro-4H-selenochromenes in the presence of phosphoric pentachloride, and synthesized new condensate aroylbenzoselenophenes. During the reactions, tetrahydro-4H-selenochromenes with phosphoric pentachloride underwent oxidative aromatization and nucleophilic substitution for a chlorine atom of one of the protons in the alicyclic fragment. Also, the narrowing of the heterocyclic fragment occurred as in synthesized selenium-containing compounds earlier transformed into the corresponding condensate aroylbenzoselenophenes.

On the Reaction of 2,5-Dihydroxy-[1,4]-benzoquinone with Diamines – Strain-induced Reactivity Effects

2020 ◽  
Vol 24 ◽  
Author(s):  
Hubert Hettegger ◽  
Andreas Hofinger ◽  
Thomas Rosenau
Keyword(s):  
Nucleophilic Substitution ◽  
Product Structure ◽  
Carbonyl Groups ◽  
Reaction Products ◽  
Double Bonds ◽  
Oh Groups ◽  
Natural Geometry ◽  
Quinoid Structure ◽  
Bond Localization

: The regioselectivity of the reaction of 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) with diamines could not be explained satisfactorily so far. In general, the reaction products can be derived from the tautomeric ortho-quinoid structure of a hypothetical 4,5-dihydroxy-[1,2]-benzoquinone. However, both aromatic and aliphatic 1,2-diamines form in some cases phenazines, formally by diimine formation on the quinoid carbonyl groups, and in other cases the corresponding 1,2- diamino-[1,2]-benzoquinones, by nucleophilic substitution of the OH groups, the regioselectivity apparently not following any discernible pattern. The reactivity was now explained by an adapted theory of strain-induced bond localization (SIBL). Here, the preservation of the "natural" geometry of the two quinoid C–C double bonds (C3=C4 and C5=C6) as well as the N–N distance of the co-reacting diamine are crucial. A decrease of the annulation angle sum (N–C4–C5 + C4–C5–N) is tolerated well and the 4,5-diamino-ortho-quinones, having relatively short N–N spacings are formed. An increase in the angular sum is energetically unfavorable, so that diamines with a larger N–N distance afford the corresponding ortho-quinone imines. Thus, for the reaction of DHBQ with diamines, exact predictions of the regioselectivity, and the resulting product structure, can be made on the basis of simple computations of bond spacings and product geometries.

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