Synthese of 4-Aryliminoparabanic Acids and 2-Arylimino-2, 3-dihydro-1, 4-thiazine Derivatives via 2-N, N'-Diarylamidinothiazolium Salts

Abstract

1, 3-Dipolar addition reaction of 2- (N, N'-diarylamidino) thiazolium salts with heterocumulenes such as isocyanate and isothiocyanate yielded 4-aryliminoparabanic acid derivatives. On the other hand, action of alkali upon the 2-amidinothiazolium salts afforded 2-arylimino-2, 3-dihydro-1, 4-thiazin-3-one derivatives providing a new ring expansion reaction of thiazolium salts to 1, 4-thiazine derivatives.