1.2.3.4- Thiatriazole-5-thiol

SYNTHESIS OF PARTICULAR CLASSES OF COMPOUNDS 4.19.9.1 Complex Formation of 1,2,3,4-Thiatriazol-5-thiol... 

Thallium triselenimidate , see Thallium 2,4,6-tris(dioxoselena)hexahydrotria-zine-l,3-5-triide, 4756 Thianthrenium perchlorate, 3449 f 3-Thiapentane, see Diethyl sulfide, 1708 1,2,3,4-Thiatriazole-5-thiol, 0385b... 

Table 7 Experimental and calculated IR and Raman spectra for 1,2,3,4-thiatriazole-5-thiol derivatives... 

The formation of complexes of l,2,3,4-thiatriazole-5-thiol has been well described in CHEC-II(1996) 1,2,3,4-thiatriazole-5-thiol can form complexes with various metals such as palladium, nickel, platinum, cobalt, zinc, etc. <1996CHEC-II(4)691>. These complexes can be prepared either by cycloaddition reactions of carbon disulfide with metal complexes of azide anion (Equation 20) or directly from the sodium salt of l,2,3,4-thiatriazole-5-thiol with metal salts. For instance, the palladium-thiatriazole complex 179 can be obtained as shown in Equation (20) or it may be formed from palladium(ll) nitrate, triphenylphosphine, and sodium thiatriazolate-5-thiolate. It should be noted that complexes of azide ion react with carbon disulfide much faster than sodium azide itself. 

The free acid, l,2,3,4-thiatriazole-5-thiol, may be prepared from hydrogen azide and carbon disulfide, but the simplest way to obtain the acid is to treat a chilled solution of the sodium salt with concen-... 

Irradiation of thiatriazole-5-thiol (18) and its anion (5) at 313 nm is reported to give rise to formation of nitrogen, sulfur, and SCN (HSCN). This scheme is in accordance with the otherwise known photochemical reactions of thiatriazoles but analytical data for product formation is not given. Quantum yields were calculated for the reaction in the pH range 0.0 to 11.8 <86POL2l 19>. 

For further reviews of thiatriazole-5-thiol and its alkylation, acylation and oxidation products see <64AHC(3)263, 76AHC(20)145, 84CHEC-I(6)579>. 

Thiatriazole-5-thiol and its salts are readily obtained from the water-soluble alkali or alkaline earth azides with CS2 at 40 °C <64AHC(3)263>. However, these salts should be handled with extreme care as violent explosions have been reported when the alkali salts are spread on a porous plate or rubbed with a spatula. The slightly soluble heavy-metal salts are very sensitive to shock even under water. An improved method for the preparation and storage of sodium thiatriazole-5-thiolate has been reported. The free acid is obtained by addition of concentrated hydrochloric acid to a chilled solution of the sodium salt but can also be prepared from hydrazoic acid and carbon disulfide (Scheme 38). 

Upon acylation of the copper complex with benzoyl chloride the corresponding 5-benzoylthio-1,2,3,4-thiatriazole is formed. The reaction product is (apparently) incorrectly assigned by the authors to 4-benzoyl-1,2,3,4-thiatriazole-5-thione based upon comparison with the product obtained from direct acylation of thiatriazol-5-thiol and citation of the older incorrect structure assignments. The thiothiatriazolato-copper(I) complexes are formulated as Cu-N(4) complexes. However, this assignment is based upon an IR band at 1200 cm attributed to a thiocarbonyl group, again upon comparison with the older literature. Further characterization therefore seems necessary. 

Photolysis of thiatriazoles was first described by Kirmse,25 who found that aryl cyanides, aryl isothiocyanates, and sulfur are formed on irradition of 5-arylthiatriazoles with UV light. Recently Okazaki et al.n reported the formation of sulfur atoms on irradiation of thiatriazoles. Photolysis of 5-phenylthiatriazole (A lax= 280 nm, e — 10800)25 in the presence of cyclohexene yielded cyclohexene episulfide. Cyclohexene thiols were not formed this was taken as an indication that the reactive species is a triplet sulfur atom. Tetramethylethylene behaves similarly.22... 

The isolated acid or its salts are shock- and heat-sensitive explosives [1]. Safe preparative procedures have been detailed [2]. Anhydrous salts should be handled only in small quantities and shielded from electrostatic discharge. Although names reflecting the preparation from azide are still in use (2005) the actual structure of the salts and disulfide derives from the cyclic l,2,3,4-thiatriazole-5-thiol, and the tautomeric thiatriazolidinethione forms the isolable free acid [3]. The heavy metal salts, though powerful detonators, are too sensitive for practical use [2]. 

Based on the calculations at the B3LYP/6-311-I— -G level and experimentally observed vibrational spectra for the ring and chain isomers, compounds 2 and 3, respectively (see Equation 2), it was concluded that the compounds existed in the cyclic form. The crucial fact is the absence of a stretching band at 2206 cm-1 in the experimental spectra that could, according to calculation, be associated with an azido group <1999PS201>. The experimental and theoretically calculated IR and Raman spectral data for l,2,3,4-thiatriazol-5-thiol derivatives are placed in Table 7. 

Thiatriazole-5-thiol 4b was described as being in equilibrium with the thione tautomer 4a (Scheme 2). The thione tautomer is predominant in acetone solution, as is apparent from the 13C NMR spectmm <1977JHC1417>. However, methylation and acylation under basic conditions occur at the sulfur atom. The analogous amino compounds do not occur as the imine tautomers. More data can be found in the earlier reviews <1964AHC263, 1976AHC145>. 

Some derivatives of l,2,3,4-thiatriazole-5-thiol were recently reported by Klapotke and co-workers <2004IC1370>. 

Phenylamino-l,2,3,4-thiatriazole 87 in principle can be prepared by heating of isomeric l-phenyltetrazole-5-thiol 170 (Equation 18) <1967JOC3580>. The formation of the thiatriazole 87 is accompanied by significant formation of phenylaminonitrile. Therefore, we recommend the use of other synthetic methods (see Section 6.09.8), for instance, the nitrosation of 4-phenyl-3-thiosemicarbazide < 1971JIC843, 1981JIG1087 >. 

The salts of thiatriazole-5-thiol react with alkyl and acyl halides to give S-alkyl and 5-acyl derivatives. Lieber et al. formulated the acyl derivatives as 4-substituted thiatriazolines, but it has been demonstrated unequivocally that both acylation and alkylation afford the 5-substituted products. A detailed discussion of this problem has been published elsewhere (76AHC(20)145). 

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