Sulfides Smiles rearrangement

Both cis- and rrans-l-arylsulfonyl-2-arylsulfenyl propenes (56) underwent a Smiles rearrangement under electron impact at 20 and 70 eV and formed a diarylsulfide ion [M — 104]+ (equation 27a)39 through a process where a bond between the R C H group and the sulfide sulfur is formed and a rearomatization occurs by a loss of the neutral thiirene dioxide or a simultaneous expulsion of SOz and propyne. The ion m/z 148 was also obtained from all of the sulfonyl-sulfides, 56 (equation 27b) and here the loss of R2 seemed to be related to the bond strength39. In addition to the above compounds 56 exhibited some simple cleavages before and after sulfone-sulfinate rearrangements. 

The a- and /3-cyclodextrins have been found to accelerate the Smiles rearrangement of 4-nitrophenyl salicylate. The reaction of 2,4-dinitrobenzenesulfonamide with acyl chlorides in the presence of excess triethylamine has been found to produce the corresponding nitrile in good yield. Mechanistic studies have indicated that the reaction proceeds via a Smiles rearrangement of the initially formed iV-(2,4-dinitrobenzenesulfonyl)amide to form the nitrile, 2,4-dinitrophenol, and sulfur dioxide (see Scheme 12). l-Chloro-3-fluorophenothiazines have been prepared by Smiles rearrangement of 3-chloro-5-fluoro-2-formamido-2 -nitrophenyl sulfides in alcoholic... 

The synthesis of phenothiazines starting with o-amino-o -halogeno-diphenyl sulfides has been a controversial problem, inasmuch as compounds like 8 may undergo an Ulmann-type cyclization to 2,8-disubstituted phenothiazines (9), or, through a Smiles rearrangement, may give 2,7-disubstituted phenothiazines (10). 

A Cr(VI) sulfoxide complex has been postulated after interaction of [CrOjtClj] with MejSO (385), but the complex was uncharacterized as it was excessively unstable. It was observed that hydrolysis of the product led to the formation of dimethyl sulfone. The action of hydrogen peroxide on mesityl ferrocencyl sulfide in basic media yields both mesityl ferrocenyl sulfoxide (21%) and the corresponding sulfone (62%) via a reaction similar to the Smiles rearrangement (165). Catalytic air oxidation of sulfoxides by rhodium and iridium complexes has been observed. Rhodium(III) and iridium(III) chlorides are catalyst percursors for this reaction, but ruthenium(III), osmium(III), and palladium(II) chlorides are not (273). The metal complex and sulfoxide are dissolved in hot propan-2-ol/water (9 1) and the solution purged with air to achieve oxidation. The metal is recovered as a noncrystalline, but still catalytically active, material after reaction (272). The most active precursor was [IrHClj(S-Me2SO)3], and it was observed that alkyl sulfoxides oxidize more readily than aryl sulfoxides, while thioethers are not oxidized as complex formation occurs. 

PFIA453, 93PFIA620, 92PFIA945). The intramolecular cyclization (via the Smiles rearrangement) of 2-nitro-2 -(/l-acetyl)-hydrazino-diphenyl sulfide yields 10-ace-tylaminophenothiazine (84PHA22). 

The acid catalyzed Smiles rearrangement of phenyl pyridyl sulfide 38 is probably due to the protonation of the ring-nitrogen atom in pyridine that increases the ease of nucleophilic substitution (56JCS1563, 62JA2770) (Scheme 21). 

Attempts have been made to synthesize azaphenothiazines by a Smiles rearrangement of 2-formamidophenyl 3 -nitro-2-pyridyl sulfide and 2-formamidophenyl-3 -nitro-4 -pyridyl sulfide (88MI1, 58JOC1906). 

However, 1-azaphenothiazines have been prepared (58JA1651) by hydrolysis of 1-acetyl-1-azaphenothiazine, obtained by Smiles rearrangement of 2-acetamidophe-nyl 3 -nitro-2 -pyridyl sulfides (in acetone-ethanol and KOH). 

The Smiles rearrangement of the sulfide 47 in the presence of potassium hydroxide in ethanol under reflux for 2.5 h flmiished the phenothiazines 48. The sulfide 47, in turn, was obtained from the reaction of aminothiophenol 44 and 2,5-dichloronitrobenzene 45 followed by formylation. ... 

The Smiles rearrangement of the S-S type was observed in the 1,4-dithiin ring opening in diazadithiapentacene 96 leading to the synthesis of 2,3 - or 3,3 -diquinolinyl sulfide or diazadithiapentacene 97 depending on the reaction conditions. ... 

Nitrophenol 141 during alkylation with 2-bromo-2-methylpropionic acid ethyl ester in the presence of cesium carbonate in acetonitrile underwent Smiles rearrangement to afford the corresponding propionamide 142. Further upon reduction of 144, which was obtained from 141 in a three step reaction, with borane dimethyl sulfide complex in THF, a Smiles rearrangement was observed furnishing the propanol 146. ... 

An unusual S-S type of the Smiles rearrangement has been observed during the 1,4-dithiin ring opening of 147 and 148 with sodium methanethiolate resulting in the formation of sulfides 149 and 150 after S-methylation. ... 

Phenothiazines 178 were obtained from the Smiles rearrangement of sulfides 176 which were, in turn, prepared from the reaction of aminothiophenol 174 and nitrobenzene 175. ... 

Among the more recent approaches to phenoxazines and phenothiazines the reductive cyclization of 2-nitrodiphenyl ethers and sulfides with trialkyl phosphites is the most interesting. Here too a spiro intermediate is involved, produced by attack of an initially formed aryl nitrene on the second aromatic ring. The sulfide (252), for example, reacts with triethyl phosphite to yield 1-methylphenothiazine (253) and it is clear that in this case ring opening of the spiro intermediate also proceeds with a rearrangement of the Smiles type (Scheme 113) (75JCS(P1)2396). 

Gonzalez JP, Edgar M, Elsegood MRJ, Weaver GW (2011) Synthesis of Huorinated fused benzofurans and benzothiophenes smiles-type rearrangement and cyclization of perfluoro(het)aryl ethers and sulfides. Org Biomol Chem 9(7) 2294-2305... 

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