Sulfimides oxidation

The transient C-nitrosoimine 193 (Ar = 4-CIC6H4) is formed by the action of ethyl cyanoformate on the sulfimide 191 and also by the oxidation of the amidoxime 192 with lead tetraacetate. In the presence of thebaine, both reactions yield an identical dihydrooxazine101. 

The oxidative conversion of the (-)-(5 )-A-tosyl methyl-p-tolyl-sulfimide 91 to the corresponding (-)-(/ )-sulfoximide 151 is of considerable interest because the absolute configurations of the substrate and product were established by the quasi-racemate method and by X-ray analysis (98), respectively. Therefore, the stereochemical result of this experiment indicates unequivocally that oxidation of chiral tricoordinate sulfur compounds proceeds with retention of configuration. 

Special cases of this reaction are the syntheses of TP betaines (53, see below) from pyrimidin-2-ylcarbamoyl chlorides and trimethylsilyl azide [89JCS(P1)1727] and of TP-1-oxides (31, see below) form pyrimidin-2-yl sulfimides and nitrile oxides [76JCS(P1)2166]. 

Another dipolar cycloaddition is that between the sulfimide 46 and p-toluonitrile oxide, giving the triazolopyridine 3-oxide 47, which can be deoxygenated by phosphorus trichloride to give the 2-(p-tolyl)triazolo-pyridine.61... 

Thiabenzenes should be considered as sulfonium betaines. They react readily with acids to give mixtures of 2H- and 4/f-thiinium salts, behave as dienes with dienophiles (Equation 9), and can be oxidized to sulfoxides. The sulfimide (450) is an aza analogue of a thiabenzene and it is oxidized by KMn04 to the corresponding sulfoximide. 

Compounds containing an ylidic N—S bond are best considered as cyclic sulfimides, and as such can be prepared by methods used for their acyclic counterparts (77CRV409). For example, oxidative ring closure of (181) with bromine gives the cyclic sulfimide (93) (64LA(675)189), and treatment of JV-(2-phenylthio)phenylbenzamidine with N-chlorosuc-cinimide (NCS) leads to the cyclic sulfimide (182) (78CC1049). 

A special oxidizing agent. A.A-dichlorotrifluorornethanesulfonamide, converts aryl trifluoro-methyl sulfides into sulfimides at room temperatures (Table 19).296 Bis(perfluorophenyl) sulfide is converted into the sulfone 12 by refluxing for an extended period with in situ prepared peracetic acid.297... 

Substituted 1,2,4-triazole 1-oxides 524 were first obtained by 1,3-dipolar cycloaddition of a nitrile oxide to S,S-dimethyl-sulfimides 523 (Scheme 154) (1974JSC(CC)486,1976JCS(P1)2166,1982JCR(M)3048). 

Dithiazoles investigated are given in Figure 1(a) these are 1,2,3-dithiazolium cations 1, 1,2,3-dithiazolyl radicals 2, l,2,3-dithiazole-3-ones 3 and related compounds 4, their 2-oxides 5. 1,2,3-Oxathiazoles have been obtained and investigated in the form of their A-oxides (Figure 1(b) and named as cyclic sulfamidates 7 and 8 and sulfimidates 6, 9, and 10. 

Cyclic sulfimidates can be easily oxidized to the corresponding sulfamidates. The preparation of sulfamidates from tvV-aminoalcohols can be achieved in one step without isolation of intermediate mono-A-oxides (Equation 37) <20010L405, 2002TL1915, 2005TA1583>. Yields are from moderate to high. 

The traditional synthesis of cyclic sulfimidates from /3-aminoalcohols and SOCl2 in the presence of amine as a base has been developed further to the preparation of the enantiopure monocyclic as well fused sulfimidates (Schemes 26 and 27). 1,2,3-Oxathiazolidine mono-.Y-oxides are readily oxidized to corresponding sulfamidates by RuCR and NalCb, and the synthesis of sulfamidates can be performed in a one-pot procedure from -aminoalcohols without isolation of intermediate sulfimidates (Equation 37). The reaction of sulfamate esters 145 with PhI(OAc)2 and various catalysts proved to be a reliable method for the enantioselective preparation of cyclic sulfamidates 146 (Equation 35). 

The l,2-diamino-4-methylthiazole 73 with phosgeniminium chloride gives the thiazolo[3,2-A [l,2,4]triazole derivative 74 (Scheme 45) <1973AGE806>. Reaction of the sulfimide 75 with nitrile oxides forms [l,2,4]triazolo[l,5- ] pyridine 3-oxides 76 in good yields (Scheme 46). This method is applicable to analogous pyrimidines and pyrazines <1976J(P1)2166, 1978BCJ563>. 

Reactions which formally involve the oxidation of azides have been reviewed by Boyer. Other oxidations with useful synthetic applications include two which start from nitrogen ylides. Sulfimides (50) derived from electron-deficient aromatic and heterocyclic amines are oxidized to the corresponding nitroso compounds by MCPBA. - This is a very useful method of preparation of some otherwise inaccessible nitroso compounds such as 2-nitrosopyridine and 1-nitrosoisoquinoline. They can be further oxidized, for example by ozone, to the nitro compounds. Phosphimides (51) are oxidized directly by ozone to the nitro compounds, although the nitroso compounds are intermediates. Isocyanates can also be oxidized to the corresponding nitro compounds, by dimediyldioxiraiK (1). ... 

A -Phthalimidonitrene was thought to be the common intermediate5 in the thermal decomposition of sulfimide l6 and aziridines 27, 3a48 and 3b8. Similarly, the aziridines 4 and 5, more readily available than 3, are precursors of nitrenes, since their thermal decomposition in the presence of cyclohexene or (Z)-4-methyl-2-pentene produces new aziridines, e.g., 68. However, these nitrene exchange methods have limited synthetic utility for the supplementary steps required for the preparation of the nitrene precursors, but can be utilized for the aziridination of alkenes sensitive to oxidants, acids or UV light, conditions that are required by other aziridination methods. 

Petfiuorotetramethylene sulfimides are synthesized by the reaction of lithium amide and pnmary amines with (perfluorotetramethylene)sulfur difluonde [7(5] (equation 13) (Table 6) The products can be oxidized with m-chloropetoxybenzoic acid to the corresponding sulfoxirmdes (equation 13) or can be treated with chlorme or bromine to yield N-halo derivatives [76] The reaction of CF3Sp3=NCF3 with nucleophiles takes place by attack of the nucleophile at the positive sulfur center [17] (equation 14)... 

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