85695-73-4Relevant articles and documents
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. Reactivity of 4'-Methoxy- and 4'-Methoxy-2-nitro-benzenesulphenanilidyl Radicals
Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
, p. 3049 - 3054 (2007/10/02)
Oxidation of 4'-methoxybenzenesulphenanilide (1a) with lead dioxide at 30 deg C afforded the NN-bis(phenylthio)-p-anisidine (7a) and 2,7-dimethoxypheazine (3a) together with minor amounts of diphenyl (4a), whereas at 10 deg C almost exclusive formation of compound (7a) and the o-benzoquinone di-imine (8a) was observed; compound (8a) was found to be thermally unstable and to give, quantitatively, compounds (4a) and (3a).The reaction products are rationalized by assuming that 4'-methoxybenzenesulphenanilidyl radicals (2a), produced by oxidation of compound (1a), undergo Cortho-N coupling to give the dimer (9a), which is responsible for the reaction products observed.A comparable trend was observed by producing the radical (2a) from reaction of compound (1a) with t-butoxy-radicals and by thermal decomposition of compound (7a).These findings rule out the nitrene mechanism previously suggested for the formation of compound (3) from oxidation of the reagent (1a).Evidence has been found that Cortho-N coupling is the main reaction path, exhibited also by 4'-methoxy-2-nitrobenzenesulphenanilidyl radicals (2c) generated from the corresponding anilide (1c) by reaction with t-butoxy-radicals or oxidation with lead dioxide, which thus rejects a previous claim that the radicals (2) (Ar = Ph and Ar = C6H4NO2-o) exhibit different chemical behaviour.
