Isothiazoles. Part II. Reaction of d-diethylamino-4-(4-methoxyphenyl)-isothiazole-1,1-dioxide with sodium azide.

3-Diethylamino-4-(4-methoxyphenyl)-isothiazole-1,1-dioxide 1, was reacted with azide ion in different solvents. Depending on reaction conditions 4-diethylamino-3a,6a-dihydro-3a-(4-methoxyphenyl)-1H-isothiazole-[4,5 -d]-1,2,3-triazole-6,6-dioxide 3 and/or 4-diethylamino-1-[3-diethylamino-4,5-dihydro-4-(4-methoxyphenyl)-5-is othiazolyl-1,1-dioxide]-3a,6a-dihydro-3a-(4-methoxyphenyl)-1H-isothia zole-[4,5-d]-1,2,3- triazole-6,6-dioxide 4 were formed. When ethanol or acetone were used as reaction solvent the formation of the above the compounds was accompanied by solvent addition forming 3-diethylamino-4,5-dihydro-4-(4-methoxyphenyl)-5-ethoxy-isothiazole-1 ,1-dioxide 6, respectively. Reaction mechanisms and structures of products are discussed.