Aniline, Sulfinyl

Before discussing Beckwith s data on that basis, a brief mention must be made of investigations by Lown s group (Naghipur et al., 1989, 1990, and other papers cited there) who claim to have observed the formation of benzoxathiete (10.63) and its valence isomer monothio-l,2-benzoquinone (10.64) in the aprotic diazotization of 2-[(2,-acetoxyethyl)sulfinyl]aniline (10.62). Scheme 10-82 is an abbreviated form of the mechanism proposed by the authors. A more detailed experimental study is clearly required. 

Some examples of three-membered chelate rings containing N and S are known. iV-Sulfinyl-aniline, and substituted forms, has been shown to bond in this manner to give chelates of the type (43) with a number of metal ions in low oxidation states. Such compounds have been reported with Ni0,150 with Rh1 and Ir1,151 and with Fe0.152 A similar bonding mode has been demonstrated for 4-(methyl)thionitrosobenzene in a bridged adduct of general form [Fe2(CO)6L].153... 

Aniline, A -(salicvlaldehydo)-photochromism, 718 Aniline, TV-sulfinyl-metal complexes, 804 Anils... 

Zur Umsctzung von N-Sulfinyl-anilin mit Phosphorigsaure-tris-[dimethyIamid] s. Lit.260. 

In the late 1980s, the reaction of organic azides and 1,3-thiazol-5-thiones (Scheme 10) to provide good yields of l,3-thiazole-5-imines (i.e., (58)) was interpreted mechanistically in terms of successive eliminations from the initially formed adduct of N2 and S via the thermally unstable thiaziridine (57) <88HCA1673>. Analogously, the photochemical reaction between aryl azides and /V-sulfinyl-anilines has been shown to yield mainly azoaromatics (59) (Scheme 11). The experimental results (including the formation of sulfur and sulfur dioxide from the presumably extruded sulfur monoxide) were interpreted in terms of the intermediacy of thiadiaziridine-1 -oxide (13). 

Diphenylcarbodiimide [1, 337-338, after first formulation]. Diphenylcarbodiimide has been prepared also by cycloaddition of benzonitrile oxide (1) with N-sulfinyl-aniline (2) and pyrolysis of the resulting 4,5-diphenyl-l-keto-l,2,3,4-thiaoxadiazole (3).2... 

However, a later study <89JCS(P2)1855> of /7-substituted A -sulfinyl aniline cycloadditions indicates a more complicated picture. A kinetic study of the reaction of a series of A-sulfinyl compounds... 

A multitude of iV-sulfinyl compounds and sulfur diimides bearing a variety of substituents on the nitrogen atom(s) have been prepared. The iV-sulfinyl compounds are commonly generated by treatment of the parent aniline, amine, sulfonamide, etc., with thionyl chloride and pyridine [Eq. 

It has been found through X-ray, neutron diffraction, and electron scattering analyses that iV-sulfinylamines, -anilines, -hydrazines, and -sulfonamides have the (Z)-3 configuration in the solid state. = The structure of iV-sulfinyl compounds in solution is known with less certainty. It has been reported that a series of aryl-substituted iV-sulfinylanilines exist solely as the Z geometric isomers in solution based on analysis of H-NMR spectra and dipole moments. However, microwave spectroscopy and C-NMR spectroscopy indicate that an E/Z equilibrium exists for some AT-sulfinylamines in solution. - ... 

Yields of the aniline derivatives are usually almost quantitative for aliphatic amines they lie between 35% and 65% if pyridine is added to bind the hydrogen chloride evolved. Sulfinylation of sulfonamides is considerably slower but gives good yields after several days refluxing. 

Benzo[2,l-c 3,4-c ]bisisothiazole (495), benzol[l,2-c 3,4-c ]bisisothiazole (496), and benzo[l,2-c 4,3-c ]bisisothiazole (497) have been prepared from easily available dimethylanilines as depicted in Scheme 38. The 2,5-dimethyl-aniline (490) was easily cyclized to the benzisothiazole (493) which upon nitration with a mixture of nitric and sulfuric acids and further reduction with iron and dilute acetic acid, yielded the aminobenzisothiazole (494). Treatment of (494) with IV-sulfinyl-methanesulfonamide afforded the benzo[2,l-c 3,4-c ]bisisothiazole (495). Analogously, (496) and (497) have been prepared from 2,4-dimethylaniline (491) and l,4-diamino-2,3-dimethylbenzene (492), respectively <80JHC533>. 

Benzyne is a necessary intermediate in the diazotization of 2-[(2-acetoxyethyl)sulfinyl(and sulfonyl)]anilines 107 and 116, but a detailed study of the way it is formed gave some surprises . Products from the aprotic diazotization of 107 included biphenylene 67 and dibenzo-l,4-thioxin 112. EPR evidence for radical intermediates was obtained. Formation of 112 requires cleavage of the S—O bond, most probably via benzoxathiete 110 as shown. Although yields of 67 and 112 were low, when the diazotization was carried out in the presence of benzyne traps such as diphenylisobenzofuran or anthracene, respectable yields (30-40%) of the corresponding benzyne cycloadducts were obtained. 

It was independently reported by Gomez Arrayas and Carretero [22] and by Zhang [23] that a (2-pyridyl)sulfinyl group is utiUzable as a removable directing group to induce regioselective alkenylation (Scheme 18.23). Gomez Arrayas and Carretero [24] also reported a similar alkenylation of N-(2-pyridyl)sulfonyl anilines (Scheme 18.24). 

Liq. SO2 poured into a Dry Ice-cooled autoclave containing a mixture of phenyl isocyanate and iron pentacarbonyl, then heated overnight at 130° N-sulfinyl-aniline. Y >90%. J. Drapier, A. J. Hubert, and P. Teyssie, Synthesis 1975, 649. 

EtAlCb catalyzes the Friedel-Crafts acylation of alkenes with acid chlorides, the formal [3 + 2] cycloaddition of alkenes with cyclopropane-1,1-dicarboxylates (eq 21), the Friedel-Crafts alkylation of anilines and indoles with ct-aminoacrylate esters, and the formation of allyl sulfoxides from sulfinyl chlorides and alkenes. EtAlCU induces the Beckmann rearrangement of oxime sulfonates. The cationic intermediates can be trapped with enol silyl ethers (eq 22). EtAlC is the preferred catalyst for addition of the cation derived from an a-chloro sulfide to an alkene to give a cation which undergoes a Friedel-Crafts alkylation (eq 23). ... 

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