1,2,3,5-Oxathiadiazines

Oxathiadiazine-2,2-dioxides, 1,4,3,5-oxathiadiazine-4,4-dioxides, and l,2,4,5-oxadithiazine-2,2,4,4-tetraoxides formed from cyano compounds and S03 93MI22. 

Two more complicated ring-contraction reactions, both yielding 4-amino-3-oxothiadiazoline 1,1-dioxides, are known. Disselnkoetter reported (71GEP1961864) that the reaction of 1,4,3,5-oxathiadiazine 127 with hydrogen cyanide produced imino derivatives 128, which were easily hydrolyzed to the corresponding oxo derivatives 89b by acid treatment (Scheme 49). The course of the reaction may involve addition of cyanide ion, decarboxylation of the resulting carbamic acid, and a nucleophilic attack at the carbonitrile group, as shown in Scheme 49. 

Certain nitriles react with the sodium salt of carbomethoxysulfamoyl chloride to afford 6-substituted 2-methoxy-1,4,3,5-oxathiadiazine dioxides 65, whereas A -chlorosulfonyl-N -methyl-N -phenylurea with an excess of... 

Reaction of sulfur trioxide with cyanogen chloride at a temperature not exceeding O C results in the formation of CSI and the 1,4,3,5-oxathiadiazine... 

The 1,4,3,5-oxathiadiazine 4,4-dioxides 62 bearing strongly electron-withdrawing substituents at both the 2- and 6-positions react with substituted cyanamides to yield 2,4,6-trisubstituted-l,2,3,5-oxathiadiazine 2-oxides 115, generally in high yield (Scheme 12) <2000RJ01523, 2002RJ0889>. 

Reactions of 2,6-di(trihalomethyl)-substituted 1,4,3,5-oxathiadiazine 4,4-dioxides 62 with substituted cyanamides in aromatic solvents (benzene, toluene, chlorobenzene, benzonitrile) furnish stable complexes 27 including 1,4,3,5-oxathiadiazine 4,4-dioxide, symmetric triazine, and solvent (or no solvent) in a ratio of 2 2 1. The molecules involved in the complexes are joined by intramolecular (van der Waals) forces into a unified, energetically favorable supra-molecular system (Scheme 15) <2005RJ0289>. 

The 1,4,3,5-oxathiadiazine 266 has been patented as an agent for reducing food intake and reducing endocrine levels <2001W00160319>. 

Cycloadditions IV-Sulfonylurethane, Me00C-N=S02 78, which is obtained in a [4-1-2] cycloreversion reaction from 1,4,3,5-oxathiadiazines, reacts with olefins, like styrene and 1,1-diphenylethylene, to give a mixture of [2-1-2] cycloadducts 79 and [4-1-2] cycloadducts 80 . 

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