Sulphides rearrangement

The thermal rearrangement of dipyridyl sulphides proceeds much easier than that of diphenyl sulphides and is highly solvent-dependent it is rapid in boiling ethanol, slower in water and does not occur at all in benzene or dimethylsulphoxide . It was also observed that 2-acylamino-pyridyl sulphides rearrange faster than the corresponding 2-amino derivatives. These facts suggest solvent participation such as shown in equation 3. 

A variety of bifunctional compounds react with the bismaleimides to form polymers by rearrangement reactions. These include amines, sulphides and aldoximes (Figure 18.41). 

Van t Hoff t-factors 565 Vinylallenes rearrangement of 748 synthesis of 737 Vinyl carbonium ions 620 17a-Vinyl-17/f-hydroxysteroids, epimerization of 735 Vinyl sulphides, as alkyl sulphoxide reduction products 930, 932 Vinyl sulphones - see also Alkenyl... 

The additional double bond in the corresponding allenyl 2-nitrophenyl sulphides causes a significant preference of the oxygen transfer to carbon88. The dominant ions correspond to the radical cations of 2[3//]-benzothiazolone and protonated benzothiazole, respectively88. Both ions require the transfer of two oxygens to carbon in the side-chain as well as extensive rearrangements of the molecules see Scheme 22. The transfer of... 

There is indirect kinetic evidence that S-nitrosation of a sulphide occurs70, followed by a S to IV rearrangement of the nitroso group, leading finally to deamination (equation 31). The evidence is based on the much higher reaction rate when the sulphur atom is present. 

The analogous oxygen compound, bis(lithiomethyl) ether (114), can also be synthesized by this method" . When bis(butyltelluriomethyl) ether (113) is treated with n-butyllithium under the same conditions, compound 114 can be generated in one step. In contrast to the sulphide 99, the doubly lithiated ether 114 undergoes a rearrangement at temperatures above —50°C, resulting in the formation of lithium 2-lithioethoxide (115) (Scheme 41). 

Nonstoichiometric compounds are mixed-valence compounds with nonintegral electron/atom ratios. Electronic properties of these compounds depend crucially on the nature and magnitude of nonstoichiometry. Electronic conduction in many such compounds occurs by hopping between the cations of different valencies (e.g. Pr " " and Pr" " in Pri2022)- Nonstoichiometry with a wide range of compositions is more common in oxides, sulphides, and related materials where the bonding is not completely ionic. In ionic nonstoichiometric compounds, structural rearrangements... 

Sulphonium ylides are in certain cases unstable and they undergo further transformation affording useful final products. In this way allylic sulphides and selenides were used to transfer an alkylthio- or alkylseleno-group onto the a-carbon of / -dicarbonyl compounds in the form of their ylides the sequence of reactions were a transylidation followed by [2,3]-sigmatropic rearrangement. 

There is evidence that atom A in scheme (76) could be carbon. Phenyl migration has been postulated to account for skeletal rearrangement in phenyl vinyl sulphides (90) initial migration through the four-centre... 

The tetragonal, mackinawite-like sulphide layers in these hydroxide/sulphide minerals (Table 3) contain various proportions of vacant M sites Feo-9S to Feo.78S " The fi actionally-occupied metal sites may be distributed in several different ways, Fig. 10 A, in tochilinite with a centred, orthorhombic motif B, in phases 1 and 2 and tochilinite III (Drits, private communication, 1979) with a simple chess-board pattern C, in tochilinite with a primitive tetragonal motif. (After long standing in aqueous suspension, the vacant sites in tochilinite I were found to have rearranged, also into a chess-board pattern, or to be completely random in their distribution . )... 

The Bamberg-Backlund rearrangement of a,a-dichlorodibenzyl sulphones leads to diarylthiiren 1,1-dioxides. The rearrangement is clean when induced by triethylene-diamine (TED) in DMSO at ambient temperatures and furnishes the thiiren 1,1-dioxides in over 90% yields. The latter on thermal decomposition eliminate sulphur dioxide and afford diarylacetylenes in over 90% yields (equation 107) . Recently it has been found that a.oc-dichlorodibenzyl sulphides can be directly converted into diarylacetylenes in 62-93% yields by refluxing them with r-BuOK in THE. ... 

Y,S-Acetylenic aldehydes have been obtained in 40-54% yields from alkenyl allenyl sulphides by a thermal [3,3]-sigmatropic rearrangement at 125-135 °C, carried out in H2O-DMSO in the presence of calcium carbonate (equation 171) . 

Aliphatic and aromatic thiols have been added to (5) -methylphenylvinylphosphine oxide (84) to provide optically active P-alkylthio- and p-arylthioethylphenylphosphine oxides (85).The reaction of the phosphine sulphide (86) with tetrachloro-o-benzoquinone gives (87) which undergoes further rearrangement. ... 

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