Thiazolium-5-thiolates

BLs-[(4-methyl-3-phenyl-l, 3-thiazolium-5-thiolat-2-yl)-thioaCetyl]-disulfan 36%... 

R2 = Ph) were presented in the previous surveys <1984CHEC(4)579, 1996CHEC-II(4)679>. However, X-ray crystal structures of closely related 3- and 5-substituted-5-anhydro-l,2,3,4-thiazolium thiolates have been reported <1999JST181> (see Chapter 6.09). 

Motesharei and Myles prepared thiazolium salts (e.g. 26, scheme 7) for the synthesis of self-assembled thiazolium thiolate monolayers on gold (fig-1) which promoted the acyloin condensation (Motesharei Myles 1997)... 

The sulfur analogues of thioisomiinchnones are 1,3-thiazolium-4-thiolates (104) and two synthetic routes to these compounds have been described by Yoshii and... 

Somewhat earlier, Souizi and Roberts (63) reported mesoionic heterocycle interconversions leading to l,3-thiazolLum-4-thiolates, l,3-thiazolium-4-olates, and l,3-dithiolium-4-thiolates from l,3-dithiolium-4-olates. This elegant chemistry, which involves cycloaddition reactions, is presented in Section 10.3.8. 

Apart from work of Yoshii and co-workers (62) described in Section 10.1.6 (cf. Scheme 10.19), no additional cycloaddition reactions of l,3-thiazolium-4-thiolates have been reported. 

Robert and co-workers (239,240) discovered novel conversions of 2-amino-1,3-dithiolium-4-olates (348) into other mesoionic heterocycles. For example, reaction of 348 with carbon disulfide, phenyl isocyanate, or phenyl isothiocyanate affords l,3-dithiolium-4-thiolates (349), l,3-thiazolium-4-olates (350), and 1,3-thiazolium-4-thiolates (351), respectively. Some of these reactions proceed via the ring-opened ketene tautomer of 348 (240). 

Basic aqueous solutions of a thiazolium cation contain the ring-opened thiolate anion 74 derived from the pseudobase 72. The observation that the uptake of two equivalents of base for the formation of the thiolate anion... 

Reaction of 2,7-diphenyl-5//,6//,7//-imidazole[2,l-/ ]-l,4-thiazolium-3-thiolate 380 with aromatic aldehydes in toluene give thiiranes 381 (Scheme 109) <2001CEJ3033>. The yields of thiiranes are collected in Table 22. 

Motesharei, K., Myles, D. C. Multistep Synthesis on the Surface of Self-Assembled Thiolate Monolayers on Gold Probing the Mechanism of the Thiazolium-Promoted Acyloin Condensation. J. Am. Chem. Soc. 1997,119, 6674-6675. 

Phenyl-6.7-dihydro-5II-(pyrrolo[I,2-c -1,3-thiazolium - l-thiolat Schmp. 193"... 

Hingegen bilden sich 2-Piperidino-l, 3-thiazolium-4-olate und -4-thiolate aus 2-Pipe-ridino-l,3-dithiolinm-Salzen und Phenyl-isocyanat bzw. -isothiocyanat erst bei hoheren Tem-peraturen und nach einem Cycloadditionsmechanismus894 ... 

Diphenyl-2-piperidino-l,3-thiazolium-4-thiolat (R = CfIL Y = S)s<5i Eine Mischung von 1 g (3,6nnnol)... 

Trisubstituierte 1,3-Thiazolium-Salze konnen mit Schwefel in entsprechende 1,3-Thi-azolium-4-thiolate iibergefiihrt werden1007 ... 

Beim Austausch der 4-Methoxy-Gruppe von 2,5-Diphenyl-4-methoxy-3-methyl-l,3-thiazo-lium-tetrafluoroborat durch ein S-Atom mit Hilfe von Natriumhydrogensulfid wird ein zwit-terionisches l,3-Thiazolium-4-thiolat gebildet1007 ... 

Phenyl-isocyanat reagiert mit 3-Phenyl-6,7-dihydro-5H--l-thiolat ebenfalls unter Cycloaddition und Eliminierung von Kohlenoxidsulfid. Allerdings entsteht ein tricyclischcs Produkt, in das drei Molekiile des Heterocumulens incorporicrt sind1686 ... 

Reactions of Thiazolium Salts. - Base-induced attack of thiazolium salts and rearrangement of subsequent 2-hydroxy-A -thiazoline was studied by u.v. kinetic spectroscopy (two consecutive irreversible steps).The first step was the nucleophilic attack of OH on C-2 of (103 R = H or Me), affording the thiazoline (104), with measured third-order rate constants. The second step was the nucleophilic cyclization of the thiolate (105) to form the thietans (106) (Scheme 9). 

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