1.3- Dithiolium salt, 2-chloro

The exocyclic chal cogen in 30 is displaced by direct chlorination,49,80 or preferably by the action of oxalyl chloride.11 The products are again (Section II,A,l,a) true 3-chloro-l,2-dithiolium salts (32), contrary to the original formulation, which involved two covalent C—Cl bonds (31). The range of application of this method and the yields obtained can be seen from Table III. 

Dimethylaniline is also C-alkylated by trithionium salts (114)70 or chloro-l,2-dithiolium salts (116),11 with elimination of methyl mercaptan or hydrogen chloride to form 113. 

Other reactions of 3-chloro-1,2-dithiolium salts with carbon nucleophiles facilitated by electron-releasing nitrogen groups include 5-aryl-3-chloro-1,2-... 

The reduction by, for example, Zn, Ag, or Ti(lll) of 3-chloro-1,2-dithiolium salts (29b), probably by dimerization of carbenes, gives bis-l,2-dithiole-3-ylidenes (9) or, in some cases, acyclic products which dimerize to 1,3-dithietanes (Scheme 6) <81LA1928, 88BSF101>. Carbenes may also be involved in the formation of bis-l,2-dithiol-3-ylidenes (9) from trisalkylthio-1,2-dithiolium salts (53)... 

Various reagents, including oxalyl chloride and thionyl chloride, convert 1,2-dithiole-3-ones (2a) and -3-thiones (2b) into 3-chloro-l,2-dithiolium salts, types (56a), some via cyclic intermediates <87PS(3l)i09>. The oxygen atom on l,2-dithiolium-3-olates (20) can be protonated or alkylated to form 4-hydroxy or 4-alkoxy-l,2-dithiolium salts respectively <86MCLC373>. 

Oxayl chloride 3-Chloro-l,2-dithiolium salts s. 19, 627 (COCl)2... 

Studies on chlorinated dithiole derivatives have continued. 4-Chloro-l,2-dithiol-3-ones of type (21) are converted by the action of oxalyl chloride into dichloro-l,2-dithiolium salts (22), which react at the 3-position with aromatic amines to give 3-arylimino-l,2-dithioles (23 R = Ar). Related structures (23 R = PhS02, MeSOa, or EtO CO) are obtained from... 

The formation of pyrazoles from 3-aryl- or 3,5-diaryl-l,2-dithiolium salts and phenylhydrazine has been investigated in some detail. 3-Chloro-... 

Oxalyl chloride (s. a. under C HJS) 3-Chloro-l,2-dithiolium salts... 

Oxidation of dithiomalonamides with hydrogen peroxide in the presence of hydrochloric acid leads to 3,5-diamino-4-chloro-l,2-dithiolium chlorides (20). The formation and deacetylation (or debenzoylation) of 3,5-diaryl-4-acyloxy-l,2-dithiolium salts have been described, and an earlier investigation of the mass spectra of the thermolysis products of dithiolium salts has been extended to include 3-alkylthio- and 3-arylthio-derivatives. Studies on the photochemical formation of 1,2-dithiolyl radicals and dithioketonate anions from dithiolium salts have been continued. ... 

The reactions of 3-chloro-l,2-dithiolium salts (23) feature in a number of papers. With secondary amines, the products are 3-amino-l,2-dithiolium salts (24), which undergo an interesting reaction with the carbanion of nitromethane to give thiophen derivatives (25). Aromatic amines, phenols, and phenol ethers are substituted at thepam-position by 3-chloro-5-phenyl-l,2-dithiolium cations. The product obtained with phenol can be deprotonated to the quinonoid compound (26), and 3-arylamino-l, 2-dithiolium salts (27 = aryl or PhCHg)... 

Addition of keten to 3-dialkylaminovinylthiones provides a route to 4,6-diaryl- or 6-aryl-2H-thiopyran-2-ones, whilst 5,6-diaryl-3-cyano-derivatives can be prepared from (3-mercapto- or 3-chloro-acroleins (22 R = SH or Cl). Full details have been published of the formation of 2H-thiopyran-2-thiones in condensation reactions between 1,2-dithiolium salts and aroyldithioacetic esters. ... 

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