Thioxanthylium salts

Benzannelated thiopyrylium species are also efficiently generated in this manner, but alternatively thioxanthylium salts (and 1-benzothiopyrylium salts) may be prepared by acid-catalyzed dehydration of the alcohols (145) and (146). The dehydration approach is obviously limited in scope. 

Catalytic reduction of thiopyrylium salts at elevated temperature and pressure yields tetrahydrothiopyrans. In like manner, 5,6,7,8-tetrahydro-2,4-disubstitutedthiochromylium salts yield the ar-disubstituted tetrahydrocyclohexa-[ Jthiopyran and octahydro-thioxanthylium salts afford the r-fused tetrahydrodicyclohexa[A< ]thiopyran (Equations 157 and 158) <2001CHE797>. 

The pentacyclic thioxanthylium salt 624 absorbs at 582 nm (emax 105 000 M-1 cm-1) with a fluorescence emission maximum at 600 nm. The dye displays photodynamic activity in vitro against chemosensitive hamster ovary cell lines (Equation 207) <2006BMC8635>. 

Triphenylthiopyrylium salts have been employed as efficient electron transfer photosensitizers to promote the [4+2] cycloaddition between thiobenzophenone and substituted styrenes. A radical cation derived from the thiobenzophenone is involved in the formation of separable diastereoisomeric mixtures of 1,3,4-trisubstituted isothiochromans <2007OL3587>. Interest has been maintained in the photosensitizing properties of thiopyrylium salts for blood disinfection <2007BMCL4406>. Several new thioxanthylium salts have been reported <2007JOC2647, 2007JOC2690>. 

H-pyrrolo[2,l-a] isoindoles quinolines quinolizines quinuclidines with 1 hetero atom other than O or N dibenzostannols dinaphthothiophenes phospholines phosphorins stibiafluorenes thieno[4, 3, 2"-4,5,6]steroids Ihietanes thiochromans thiophenes thiopyrylium salts thioxanthylium salts with 2 0-atoms benzodioxanes benzofuro[2,3-b]benzofurans chromeno [3,4-bJ chromenes coumarinocoumarones dibenzo-p-dioxins... 

It has been shown that the product obtained by the action of phosphorus pentachloride on thioxanthone is the thioxanthylium salt (85). Reduction of thioxanthylium perchlorate with zinc (in the absence of oxygen) gives the bimolecular product (86), but with 9-phenylthioxanthylium perchlorate... 

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