Thia thiatriazines

Thiatriazines arc not naturally occurring compounds. The nomenclature of 1,2,4,6-thia-triazines is based on the IUPAC rules and Chemical Abstracts.1 2 The valence state of the sulfur atom is assigned with the Greek letter lambda (/.). In this section, the chemistry of the ring system of 124,2,4,6-thiatriazines with three-coordinated sulfur and of the l/4,2,4,6-thiatriazine 1-oxides or 1-imides with four-coordinated sulfur with maximum unsaturation is described. A review of the literature until 1990 is available3 and also a more recent review.82... 

Thiatriazines mentioned herein are described in the following manner. 1 a4,2,4,6-thiatriazines 1, covering the tautomeric forms of 3,4-dihydro-04,2,4,6-thiatriazines 2, 2,3-dihy-dro-lA4,2,4,6-thiatriazincs 3,2/7-124,2,4,6-thiatriaziiie 1-oxides or -imides 4, 4//-12.4,2,4,6-thia-triazine 1-oxides or -imides 5, 126,2,4,6-thiatriazine 1-oxides 6, l/.6,2,4,6-thiatriazine 1-imides 7, and 1,2,4,6-thiatriazinium salts 8. 

The energy difference between 277-1,2,4,6-thiatriazines 1 and the corresponding 477-tautomers T is very small. Hence, temperature-dependent tautomeric equilibria are observed in solution. With special NMR techniques it was shown that a few percent of the tautomeric 124,2,4,6-thia-triazine 1" is present.34,54"55... 

In contrast to dithiocarbamoylthiatriazines vide supra), the reaction of 3,5-dichloro-JV,lV-diiso-propyl-1 A4,2,4,6-thiatriazin-l-amine with piperidinc-1-carbonylthiolate gives the extremely unstable, not isolable 3-chloro-Ar,A -diisopropyl-5-[(piperidinocarbonyl)sulfanyl]-l /4,2,4,6-thia-triazin-1-amine (compound 19d, Section 2.1.1.5.5.3.), which eliminates carbon oxysulfide giving the corresponding 3-chloro-Ar,Ar-diisopropyl-5-piperidino-124,2,4,6-thiatriazin-l-amine.43,45... 

Methods for the preparation of 1-oxides are described in Section 2.1.1.5.1. Oxidation of thia-triazines, thiatriazine 1-oxides and thiatriazine 1-imides proceeds in aqueous solution with oxidizing agents such as permanganate, periodate, hydrogen peroxide, peracids, e.g. 3-chloroperoxybenzoic acid, and by catalysis. 

Chloro- and fluorosulfonylcarbamoyl chlorides were found to react with aminotriazole (42) to give [l,2,4]triazolo[5,l-c][l,2,4,6]thiatriazine-l,1-dioxide (43) <77JCR(S)238>. A thiazole-fused thia-triazine-dioxide (45) was prepared from the aminothiazole derivative (44) by chloro-sulfonylisocyanate. The observed regioselectivity in this reaction was interpreted by the preference for nucleophilic addition at the more electrophilic isocyanate which was followed by the cyclization at the sulfonyl chloride <87JMC2058>. 

Dihydro-l,3,2,4,6-thia(VI)thiatriazin-5-one 3,3-dioxides from N-carbalkoxysulfamoylsulfone diimines... 

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