Oxokohlenstoffe und verwandte Verbindungen. 33 [1]. Über die Umsetzung von 3-Antipyryl-4-hydroxy-cyclobutendion mit Aminen: Antipyryl-arylamino-quadraine – eine neue Klasse von C,N-Quadrainen / Oxocarbons and Related Compounds. 33 [1]. On the Reaction of 3-Antipyryl-4-hydroxy-cyclobutenedione with Amines: Antipyryl-arylamino-squaraines – a New Class of C,N-Squaraines

Antipyryl-arylamino-squaraines (11a -w) have been prepared by condensation of 3-antipyryl-4- hydroxy-cyclobutenedione (9a) with the primary aromatic amines 10a -w, using preferentially EtOH as the reaction medium. Surprisingly, 3-antipyryl-4-hydroxy-cyclobutenedione (9a) and 4-aminoantipyrine (13), under similar conditions, yielded 3-antipyryl-4-antipyrylamino-cyclobutenedione (14a), and not the expected squaraine. Reactions of 9a with the o-phenylenediamines 16a and 16b afforded the quinoxalines 17a and 17b, respectively