Thianthrene

A mixture of 120 g. (0.89 mole) of sulfur monochloride and 200 g. (2.56 moles) of benzene is heated on a water bath with stirring while 100 g. (0.75 mole) of anhydrous aluminum chloride is added slowly in small portions. The reaction mixture is heated for 2 hours longer, then cooled, and a mixture of crushed ice and hydrochloric acid is added slowly. The mixture is steam-distilled for 3 hours. The solid residue in the flask is triturated with ether, and the remaining solid is recrystallized two times from methyl ethyl ketone to give thian-threne melting at 154° in 25-30% yield. 

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XIX XIX, 1st 1934 2666-3031 Two Cyclic Oxygens. Stem nuclei Dioxan, 1. Thianthrene,... 

Electrochemiluminescence quantum yields of 8—10% from 9,10-diphenylanthracene and 14—20% from the 9,10-diphenylanthracene anion—thianthrene cation combination have been reported using the rotating ring disk electrode technique (157,173). 

The earliest reported reference describing the synthesis of phenylene sulfide stmctures is that of Friedel and Crafts in 1888 (6). The electrophilic reactions studied were based on reactions of benzene and various sulfur sources. These electrophilic substitution reactions were characterized by low yields (50—80%) of rather poorly characterized products by the standards of 1990s. Products contained many by-products, such as thianthrene. Results of self-condensation of thiophenol, catalyzed by aluminum chloride and sulfuric acid (7), were analogous to those of Friedel and Crafts. 

The first reported assignment of the PPS stmcture to reaction products prepared from benzene and sulfur in the presence of aluminum chloride was made by Genvresse in 1897 (8). These products were oligomeric and contained too much sulfur to be pure PPS. Genvresse isolated thianthrene and an amorphous, insoluble material that melted at 295°C. These early synthetic efforts have been reviewed (9—11). 

Unsaturated ketones react with phenyUiydrazines to form hydrazones, which under acidic conditions cyclize to pyrazolines (35). Oxidation, instead of acid treatment, of the hydrazone with thianthrene radical cation (TH " ) perchlorate yields pyrazoles this oxidative cyclization does not proceed via the pyrazoline (eq. 4). 

X-ray, 3, 947 <63AX310> trans-Thianthrene 5,10-dioxide dipole moment, 3, 947 <65JCS571)... 

Thianthrene, 2,3,7,8-tetramethoxy-dication, 3, 968 Thianthrenedicarboxylic acids applications, 3, 993 Thianthrene-2,6-dicarboxylic acids... 

On distillation of the residue in the distillation flask there is obtained a fraction boiling at i70-200°/i8 mm. Crystallization of this material from methyl alcohol yields 8-10 g. of thianthrene, melting at 155-156°. 

Diphenyl sulfide can best be prepared by treating benzene and aluminum chloride with sulfur chloride, sulfur dichloride, or sulfur. In addition to diphenyl sulfide there are found traces of thiophenol and varying amounts of thianthrene. 

Thianthrene [92-85-3] M 216.3, m 158°. Crystd from Me2CO (charcoal), AcOH or EtOH. Sublimes in a vacuum. 

A different approach leading to thianthrene derivatives starts from 0-ethyl or 0-isopropyl dithiocarbonate 394, when heated with chlorodinitrobenzene derivative 59 provided intermediate 395, the compound having all features necessary for denitrocyclization reaction to the final product 396, which was the only isolated compound (Scheme 61). Its structure was assigned by X-ray crystallography (77JOC2896). 

Adam and Lohray122 have used thianthrene 5-oxide (88) as a mechanistic probe in oxidations with transition metal peroxides. They oxidized 88 with various diperoxo complexes of chromium, molybdenum and tungsten and formulated a plausible mechanism on the basis of the products formed, 89 and 90. 

The formation of adduct is followed by fragmentation and subsequent H-atom abstraction reaction from the sulfinic acid produced. Strong acid solutions of aromatic sulfoxides like thianthrene 5-oxide (7) or phenothiazine 5-oxide (8) gives rise to ESR signals, which... 

The most evident of these is the marked stability of radical cations formed in an aprotic medium by the oxidation of compounds where the first ionization potential (in the sense of photoelectron spectroscopy) is for the removal of an electron from a non-bonding orbital, e. g. thianthrene... 

The introduction of substituents into the 1- and 2- positions of thianthrene can be achieved by deprotonation at C-1 and subsequent reaction with electrophiles and by formation of 2-lithiothianthrene from the corresponding bromo compound <96JCS(P1)2391>. Selective oxidation of both thianthrene and its 5-oxide have been described <96CEJ255, 96JCS(P1)2693>. 

Likewise, pyridines such as methyl isonicotinate 1999 or quinolines are readily oxidized by BTSP 1949 in the presence of HOReOs in CH2CI2 to give, after 6 h at 24°C, 98% yield of, e.g., methyl isonicotinate N-oxide 2000 [174] (Scheme 12.49). The oxidation of diphenylsulfide with BTSP 1949 and triphenylphosphine dichloride in acetonitrile results, after 60 h at room temperature, in only 12% diphenyl sulfoxide 2001 and 88% recovered diphenyl sulfide [175] (Scheme 12.49), whereas thianthrene 5-oxide 2002 is oxidized by the peroxy-Mo complex 2003 to give 58% of a mixture of 2004 to 2007 in which the trans 5,10-thioxide 2005 predominates [176] (Scheme 12.50). 

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