1,2,4,6-Thiatriazine 1-oxides

Reactions of arylchloromethyl-p-tolyl sulfoxides with tetrasulfur tetranitride (S4N4) yield 3,5-diaryl-1,2,4,6-thiatriazine 1-oxides <00T7153>. [4+2] Cycloadditions of thiazyl... 

Chloro-l A6,2,4,6-thiatriazine 1-Oxides from 4//-1,2,4,6-Thiatriazine Oxides... 

Thiatriazines. Oxidative cyclization of product from thiosemicarbazides -f (aryl isocyanates (Scheme 30) or benzonitriles (Scheme 31)). 

N-alkylsulfonylaminosulfonyl ureas and pyrimido (triazino) thiatriazine oxides as their intermediates... 

The pyrido[l,2,4,6]thiatriazine-5(6/7)-one 1,1-dioxide 2 was found to be useful in the treatment of nitric oxide synthase-mediated diseases and disorders <1996W018617>. 

Reaction of 1,2,4,5-tetrazines (39) with AMhionitrosodimethylamine (217) and N-sulfinylanilines (218) led to the isolation of 4-dimethylamino-4// -1,2,4-triazoles (219) and 4-aryl-4//-1,2,4-triazoles (220), respectively. The formation of these products was explained by a [4 + 2] cycloaddition to give bicyclic intermediates, then elimination of nitrogen to yield the 1,2,4,5-thiatriazines, which form the products by extrusion of sulfur and sulfur oxide, respectively (Scheme 12) (79CZ230, 77AP269). 

N-Sulfinylamines are useful N—S two-atom fragments and react readily with a-ketoketenes to give l,2,3-oxathiazin-4-one 2-oxides (77JCS(P1)904,79CB1012). Reaction with azoalkenes gives 1,2,3,6-thiatriazines (77S305) as shown in Scheme 23. 

Two articles have appeared very recently dealing with ring expansion of l, 2,3,5-thiatriazoles to 1,2,4,6-thiatriazines <20070BC472> and with the transformation of pyranopyrimidines to 1,2,3,5-thiatriazolopyrimidine-l-oxide... 

The thermal decomposition of the dithiatetrazocine 44 produced the thiatriazine-1-oxide 45 in good yield (Equation 12) <2000IC1697>. It was found that photolysis of 44 also engendered the ring contraction, but thermolysis provides a cleaner route to the cyanuric-sulfanuric heterocycle 45. 

C4H,Cl3F3N3OS 2H-1,2,4,6-Thiatriazin 3-Trichlor-methyl-5-trifluormethyl- -1-oxid E9c, 821 (S-C1-S = 0)... 

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. 

Using a second equivalent of jV-sulfinylarenesulfonamide the corresponding heterocyclic sulfur diimides are formed, which cyclize immediately to thiatriazines 3 and 6. In an alternative reaction path, some of the compounds directly afford the corresponding thiatriazine 1-oxides.5 3... 

Rearrangements of methyl derivatives, e.g. transmethylations, have not been observed. For example, 4-methyl-3,5-bis(4-tolyloxy)-l/J.4,2,4,6-thiatriazine 1-oxide (2, R = 4-Tol) could not be transformed into the isomeric l-methoxy-124,2,4,6-thiatriazine 3.69... 

Using sulfuryl chloride, oxidative chlorination of 3,5-diphenyl-4//-l,2,4,6-thiatriazine gives 1-chlorothiatriazine 4.47 The same procedure gives 4 in 8% yield by reaction of sulfuryl chloride with the dimer bis(3,5-diphenyl-l,2,4,6-thiatriazinyl)48... 

Only one example is known of the conversion of 4/f-l, 2,4,6-thiatriazine 1-oxides to the corresponding 1-chlorothiatriazine 1-oxides. Oxidative chlorination of 3-phenyl-5-(trichloromethy 1)-4//-thiatriazine 1-oxide with fer -butyl hypochlorite or /V,/V-dichloroLosylamine gives the corresponding 1-chloro compound 5.47,62 1-Chlorothiatriazine 1-oxides such as 5 are stable crystalline compounds. 

An S-N moiety can be transferred from 1,3,5,2,4,6-trithiatriazines for construction of thiatri-azines (see Section 2.1.1.2.). The reverse procedure is possible in the case of l/l2,5A4,2,4,6,8-dithiatetrazocine 1 which loses an S-N moiety. Thus, treatment of 1 with ozone in dichloromethane at —78 °C gives 3,5-diphenyl-4/jT-l,2,4,6-thiatriazine 1-oxide (2) in 38% yield and the corresponding 1,1-dioxide 3 in 5% yield.63... 

As known from other heterocyclic systems, oxidation to S-oxides depends sharply on the electronegativity of the substituents. Hence, it would be expected that 1-alkyl- or 1-aryl-substituted thiatriazines arc capable of oxidation. 

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