- TBAI-mediated sulfenylation of arenes with arylsulfonyl hydrazides in DPDME
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An efficient TBAI (tetrabutylammonium iodide)-mediated C–H sulfenylation of arenes with arylsulfonyl hydrazides in dipropylene glycol dimethyl ether (DPDME) was described. Various electron-rich arenes were applicable in the reaction, such as naphthylamine, naphthol, aniline, indole, pyrrole, and imidaz o [1,2-a] pyridine. A wide range of the aryl sulfides were obtained with good functional group tolerance. This method features green reaction conditions (odorless and easily available sulfur reagent, recyclable TBAI, and DPDME as solvent), and broad substrate scope. The synthetic potential is demonstrated by gram-scale synthesis and downstream transformations. The mechanism studies show that the reaction is achieved through electrophilic substitution process, and diaryl disulfide may be the main intermediate.
- Jie, Zhang,Jing, He,Ping, Liu,Xuezhen, Li,Yali, Liu,Yueting, Wei
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supporting information
(2020/10/13)
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- Acid-promoted Decomposition of Benzenesulphenanilides and N-Aryl Bis(benzenesulphen)amides
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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).
- Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
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p. 2261 - 2266
(2007/10/02)
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