Arthur H. Schmidt

Ein neues, einfaches Verfahren zur Darstellung von Ammonium- und Phosphonium-Betainen der Quadratsäure

Abstract Squaric acid 1 reacts with equimolar amounts of tertiary amines 7 and tertiary phosphines 8 in acetic anhydride to afford the monocondensation-products 4 and 5 , respectively.

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 Graphical Abstract 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

Oxocarbons and related compounds. Part 28.1 Polycycle-fused dihydrobenzocyclobutenediones and benzocyclobutenediones. Synthesis of cyclobuta[c]- and cyclobuta[a]-phenanthrene-1,2-diones and cyclobuta[a]triphenylene-11,12-dione

The Diels–Alder reaction of semisquaric chloride 5 with 1-(alk-1-enyl)naphthalenes, 2-(alk-1-enyl)naphthalenes and 9-vinylphenanthrene is used to prepare dihydrocyclobuta[c]phenanthrene-1,2-diones 8a–c, dihydrocyclobuta[a]phenanthrene-1,2-diones 12a–c, and dihydrocyclobuta[a]triphenylene-11,12-dione 18, respectively. Treatment of the dihydrocyclobutaarenediones with bromine effects aromatization and opens up a route for the synthesis of cyclobuta[c]phenanthrene-1,2-diones 9a–c, cyclobuta[a]phenanthrene-1,2-diones 13a–c and cyclobuta[a]triphenylene-11,12-dione 19. The range of Diels–Alder reactions with semisquaric chloride 5 is extended to the use of 4-(prop-1-enyl)-1,2-dihydronaphthalene 14. Tetrahydrocyclobuta[a]phenanthrene-1,2-dione 15 is obtained in 69% yield, which can be oxidized, stepwise or at once, to give cyclobuta[a]phenanthrene-1,2-dione 13b in good yields.

RK. MIT CYCLOBUTENDIONEN 30. MITT. 3‐MERCAPTO‐4‐PHENYL‐3‐CYCLOBUTEN‐1,2‐DION

Beim Eintropfen benzolischer Losung des Cyclobutendions (I) in die mit H2S gesattigten Pyridine (II) bilden sich die Salze (III), die mit konz. HCl zu der Titelverbindung (IV) hydrolysiert werden.