Isothiazoles. Part X. New 3-substituted-2-arylpropenamidines by base catalyzed ring opening of 3-amino-4-arylisothiazole 1,1- dioxides

Starting from 5-unsubstituted or 5-alkyl-, aryl-, heteroarylsubstituted 3-diethylamino-4-arylisothiazole 1,1- dioxides by base induced ring opening 3-alkoxypropenamidines were synthesized in excellent yields in a mild and efficient way. When 5-bromo-3-diethylamino-4-arylisothiazole 1,1-dioxide was used as the reagent, 3,3-dialkoxy-propenamidines, a new class of unsaturated amidines, were obtained. By using Grignard reagents 3-substituted acrylamidines can be produced.