SYNTHESIS, HYDROLYSIS REACTIONS AND CONFORMATIONAL STUDY OF 2-SUBSTITUTED 3,5-DIAMINO-4-NITROSO-2H-1,2,6-THIADIAZINE 1,1-DIOXIDES

The 2-substituted 3,5-diamino-4-nitroso-2H-1,2,6-thiadiazine 1,1-dioxi des are present in solution as a mixture of two rotational conformers of the nitroso group that are stabilized by hydrogen bonds with the am ino groups in positions 3 and 5. The stability of these conformations has been studied using H-1, C-13 and N-15 NMR spectroscopy as well as molecular orbital ab initio calculations, In addition, hydrolysis reac tions of these compounds have been carried out affording ydroxyimino-3 -oxo-3,4-dihydro-2H-1,2,6-thiadiazine 1,1-dioxides and 4-amino-3-oxo-2 ,3-dihydro-1,2,5-thiadiazole 1,1-dioxides.