Reactions of 1,2.,5-thiadiazole 1,1-dioxide derivatives with nitrogen nucleophiles. Part IV. Addition of alpha-diamines

alpha-diamines, such as ethylendiamine and o-phenylendiamine, add to 3,4-aryl-disubstituted 1,2,5-thiadiazole 1,1-dioxides to give dihydropyrazines or quinoxalines, respectively and sulfamide. The new compound acenaphtho [5,6-b]-2,3-dihydropyrazine was synthesized and characterized. The addition of ethylendiamine to 3,4-diphenyl-1,2,5-thiadiazoline 1,1-dioxide gives 3,4-disubstituted thiadiazoildine 1,1-dioxide, dihydropyrazines, or pyrazines, depending on the reaction condition used. The reactions were followed by cyclic voltammetry and NMR spectroscopy which, in some cases, allowed the detection of the thiadiazolidine intermediate. Copyright (c) 2008 John Wiley & Sons, Ltd.Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET)Consejo Nacional cle Investigaciones Cientificas y Tecnicas (CONICET)Comision de Investigaciones Cientificas de la Provincia cle Buenos Aires (CIC Pcia. Bs.As.), ArgentinaComisión de Investigaciones Científicas Provincia de Buenos Aires (CIC) - ArgentinaUniversidad Nacional de La Plata (UNLP)Universidad Nacional de La Plata (UNLP