Thiatriazol-5-enes

4-Thiatriazol-5-enes (Anhydro-5-alkyl-l,2J,4-thiatriazolium Hydroxides) (301) 

The salts (298) and malononitrile yield the orange biscyanomethylene derivatives (301). The compound 301, R = Ph, has a dipole moment of 8.84 D in benzene.212 

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Thus, bis(trifluoromethyl)thioketene 156 reacts with hydrazoic acid to afford the 5-hexafluoropropyl-2-ene derivative that tautomerizes to hexafluoroisopropyl-l,2,3,4-thiatriazole 157. In contrast to other 5-alkylderivatives of 1,2,3,4-thiatriazole this compound was reported to be stable at room temperature (Scheme 37) <1970JOC3470>. 

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