82993-63-3Relevant academic research and scientific papers
Acetamidinosulphenylation of Alkynes via Electrophilic Addition of 4'-Substituted Benzenesulphenanilides in Acetonitrile
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 1105 - 1111 (2007/10/02)
A number of 4'-substituted benzenesulphenanilides and N-methyl-4'-nitrobenzenesulphenanilide are shown to add to simple alkynes in acetonitrile in the presence of boron trifluoride-diethyl ether to give acetamidinovinyl sulphides in varying yields.Addition is largely favoured by dialkyl substitution on the alkyne and by electron-attracting anilide substituents.Moreover, the azasulphenylation adducts are produced with trans stereospecificity and high regioselectivity (Markovnikov orientation).A likely mechanism involves nucleophilic displacement by the alkyne at the activated sulphur of the anilide complexed with boron trifluoride leading to the initial formation of a thiirenium ion intermediate.Subsequent back-side attack of acetonitrile on the thiirenium ion gives a nitrilium ion which is ultimately trapped by the liberated arylamine.
Acid-promoted Decomposition of Benzenesulphenanilides and N-Aryl Bis(benzenesulphen)amides
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 2261 - 2266 (2007/10/02)
The decomposition of 4'-substituted benzenesulphanilides (1a-d) in the presence of trifluoroacetic acid (0.6 equiv.) leads to N-arylbis(benzenesulphen)amides (6a-d) in variable yields, depending on the 4'-substituent, in addition to disulphide (4) and anilines (3a-d), whereas products arising from sulphenylation of the N-aryl ring result from 3'-methoxybenzenesulphenanilide (1g).The 4'-nitro- and 3'-nitro-benzenesulphenanilides (1e,f) react with a slight excess of trifluoroacetic acid to give only (4), the thiosulphonate (5), and aniline (3e,f).The findings are interpreted in terms of possible nucleophilic attack at the S-N bond of a protonated sulphenanilide by the nitrogen or the N-aryl ring of another sulphenanilide unit, according to the nature of the substituent and its position, with displacement of aniline (3).The reaction of (1a-d) with 1.5 equiv. of trifluoroacetic acid leads to complete disappearance of the initially formed amides (6a-d) with concomitant formation of phenazines (9) and/or p-quinone di-imines (8).Similar results are obtained by using boron trifluoride-diethyl ether.Di-imines (8) and phenazines (9) are explained on the basis of a mechanism initially involving nucleophilic attack by (1) and/or (6) and/or (3) at the ortho and para positions of an intermediate cation, possibly (18A) or (18B), and loss of the disulphide (4).
Benzenesulphenanilidyl Radicals. Part 3. Reactions of 4'-Substituted Benzenesulphenanilides with t-Butoxyl Radicals
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 1577 - 1582 (2007/10/02)
Decomposition products of the 4'-substituted benzenesulphenanilidyl radicals (2a, b, d, and e), generated from the corresponding benzenesulphenanilides (1) with t-butoxyl radicals, have been investigated in benzene, acetonitrile, and acetone.Results indicate that the decomposition modes exhibited by these radicals are not essentially influenced by variation of the solvent polarity; comparison of the findings with present and previous results from oxidation of (1) with lead dioxide show that the chemical reactivity trend displaced by the thioaminyls (2) can be greatlyinfluenced both by the reaction medium and the 4'-substituent.Evidence is presented that the benzenesulphenanilides (1b) and (1e) react in acetone in the presence of di-t-butyl hyponitrite to give products ascribable to homolytic substitution at the sulphenanilide sulphur by acetonyl radicals.
Benzenesulphenanilidyl Radicals. Part 2. Substituent and Solvent Effects on the Reactivity of 4'-Substituted Benzenesulphenanilidyl Radicals Produced by Oxidation with Lead Dioxide of the Corresponding Benzenesulphenanilides
Balboni, Claudio,Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 2111 - 2117 (2007/10/02)
Oxidation of benzenesulphenanilide (1d) with lead dioxide in benzene affords the p-benzoquinone diimine (5d) together with minor amounts of N,N-bis(phenylthio)aniline (4d) and diphenyl disulphide (7a).The formation of the products is explained in terms of p-C-N coupling of the benzenesulphenanilidyl radicals (2d) and subsequent fragmentation of the resulting dimer.A similar trend is observed in the oxidation of 4'-chloro- and 4'-bromo-benzenesulphenanilides (1e) and (1f), whereas 4'-nitrobenzenesulphenanilide (1g) leads to the o-phenylenediamine (12g), arising from o-C-N coupling of the sulphenanilidyl radical (2g).The oxidation of the sulphenanilides (1e) and (1f) in acetonitrile produces the phenazines (3e) and (3f) and the disulphide (7a), whereas the anilide (1g) and 4'-cyanobenzenesulphenanilide (1h) give azobenzenes (11g) and (11h) and the disulphide (7a); these results are discussed in terms of a possible mechanism involving oxidation of the N-N dimers (14e-h) which are in rapid equilibrium with the corresponding sulphenanilidyl radicals (2e-h).Evidence is also presented that the oxidation of 2-nitrobenzenesulphenanilides leads to products ascribable to intermediate 2-nitrobenzenesulphenanilidyl radicals, in contrast with a previous claim.
The Conjugated N,N'-(Polyenediylidene)bis-sulphenamide Chromophore. Part I. N,N'-Bisarylthio-quinone Diimines
Shand, Charles A.,Thomson, Ronald H.,Greenhalgh, Colin W.
, p. 1601 - 1617 (2007/10/02)
N,N'-Bisarylthio-quinone diimines have been prepared from p-phenylenediamines and arenesulphenyl chlorieds, and from N,N'-dichloroquinone diimines and thiols.They are intensely coloured (the N,N'-dialkyl derivatives also) and exhibit Z/E isomerism in solu
