L,2-Benzodithiole-3-thione

Carbon oxysulfide and sodium hydride react with 4,5,6,7-tetra-hydro-l,2-benzodithiole-3-thione in dimethyl sulfoxide (DMSO), giving a dianion (28) which, by action of methyl iodide, gives a dithiolic thio ester (29). On standing, 28 partly isomerizes to 30, which, by methylation gives the dithiolone 31.23... 

Although this reaction gives good results with aryl-1,2-dithiole-3-thiones, it does not work well with aromatic fused rings such as l,2-benzodithiole-3-thione. Some examples of this reaction are given in the preparations of the... 

Benzhydroximic chloride added at 80° to a soln. of 7-(5-phenyl-l,2-dithiol-3-ylidene)-4,5,6,7-tetrahydro-l,2-benzodithiole-3-thione in xylene, then a slight excess... 

Strained olefins add to the dithiole-thione (375) to give rearranged products thus norbornadiene affords (376). l,2-Benzodithiole-3-thione (377) and cyclo-pentene form the photoadduct (378). ... 

These structures may be named as follows 7, l-(l,2-benzodithiol-3-ylidene)propane-2-thione and 8, 6-(5-methyl-l,2-dithiol-3-ylidene)-2,4 -cy clohexadiene-1 -thione. 

Another semidegradative synthesis is the reaction of 3-methylthio-1,2-benzodithiolium sulfate with malonic acid. It does not give, as initially thought,65 a 3-[(l,2-benzodithiol-3-ylidene) methyl]-l,2-benzodithiolium ion, but in fact a 2-(l,2-benzodithiol-3-ylidene)-2JT benzo[6]thiophene-3-thione (45).40... 

A further example of the same type of rearrangement is afforded by the l 2-benzisothiazoline-3-thiones. If the benzisothiazolium salt (40) is treated with thioacetic acid, the product is the 3-arylimino-3/f-1,2-benzodithiole (41), provided R is an aryl group when R is alkyl, the product is the benzisothiazoline-3-thione (42).32 Structures of types 41 and 42 are, however, in equilibrium with each other at 150°, presumably via a dipolar intermediate [Eq. (3)].32 A diradical... 

With the exception of the compounds mentioned in Section II, C, 3, all l,2-benzisothiazoline-3-thiones (46) have been prepared by the reaction between a benzodithiole-3-thione ( trithione ) (45) and a... 

A full account has been given of photoadditions of l,2-dithiole-3-thiones with olefins, Similar reactions with benzodithiole-3-thione (7 X = S) lead to blue quinonoid compounds (12), which in solution, at room temperature, are in equilibrium with dimeric forms. ... 

Method BAOi A titanium autoclave of 50-mL capacity was charged with a l,3-benzodithiole-2-thione (0.5 mmol), sulfur (as S8) (0.128 g, 0.5 mmol) and NH3 (1) (30 mL). The autoclave was closed and the mixture was stirred at 20 C for 30 min. The resulting solution was added dropwise through a needle bulb to benzene (80 mL) containing 1,3-dinitrobenzene (0.084 g, 0.5 mmol) and the mixture was stirred at 20 C until all the NH3 had evaporated (ca. 2h). The resulting solution was evaporated and the residue was chromatographed (silica gel, CC]4/hexane) to give the yellow crystalline product. 

Unexpectedly, upon reacting commercially available ethylene trithiocarbonate 111 with benzyne, the salt 103a was obtained as the major product along with a small amount of l,3-benzodithiole-2-thione 109a, as shown in Equation (31) <1996CC205> and <1996BCJ2349>. 

The l,3-benzodithiole-2-thione derivative (290) is obtained by refluxing an aqueous solution of 1,2-benzenedithiol (289) and carbon disulfide in the presence of sodium hydroxide (72S29). 

An approach to nitro-substituted l,3-benzodithiole-2-thiones (325) is based on the reaction of l-chloro-2,6-dinitrobenzenes (323) with sodium f-butyl trithiocarbonate which yields dinitrophenyl f-butyl trithiocarbonates (324). The latter cyclize on heating in acetic acid with formation of nitro-l,3-benzodithiole-2-thiones (325) (80JOC4041). 

The reaction of benzyne with l,3-benzodithiole-2-thione 188 in 1,2-dichloroethane gave the bicyclic sulfonium chloride 190 by trapping of the intermediate 189 (Scheme 21) <1996CC205>. 

Benzyne (generated from 7 or from 9) also reacted with l,3-dithiolan-2-thione (163) to give l,3-benzodithiole-2-thione (164) (9-13%).92 Evidence for... 

Another route was proposed by Sato and co-workers. The synthesis of benzopentathiepins (35), (39), (52), and (53) was carried out by reactions of corresponding l,3-benzodithiole-2-thione or 1,2-benzenedithiol with elemental sulfur in liquid ammonia <86CL349, 88801647, 90YGK797). Per-hydrobenzopentathiepine (49) was obtained analogously (Scheme 33) <88801647). 

The major forms of iso thiocyanates present in urine are N-acetyl-cysteine conjugates (mercapturic acids) and these have been measured using HPLC with MS detection (Chung et al 1992 Conaway et al 2000 Fowke et al 2003 Petri et al 2003 Rouzaud et al 2004). Appropriate standards can be readily synthesized. Figure 8.9 shows the reaction of an isothiocyanate with 1,2-benzenedithiol which gives rise to a cyclo-condensation product (l,3-benzodithiole-2-thione) and an amine (R-NH2). 

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