The first and the second half-wave potentials of p-tropoquinones measured by CV are linear to the Hammett’s Σσp and Σσm, respectively. Their smaller electrostatic repulsion than p-benzoquinones can be attributable to the characteristic three carbonyl system.

Unlike the benzenoid equivalent, p-methoxyphenol, the cerium(IV) ammonium nitrate (CAN)-oxidation of 5-hydroxy-2-methoxytropone gave C–C coupling products. On the other hand, either by thallium(III) nitrate (TTN) or CAN at 50 °C, 5-hydroxytropolone, a free tropolone, gave 3-methoxy-p-tropoquinone together with p-tropoquinone and 8-oxabicyclo[3.2.1]octenone derivatives, but no dimeric product.

The thallium(III) nitrate-oxidation of 2-alkoxy-5-hydroxytropones gave, in good yields, the mono- and diacetals of tropoquinones, which can be used for the introduction of oxygen functions to the seven-membered nucleus and preparation of the substituted tropoquinones. An improved synthesis of 4-methyl-p-tropoquinone or 4-methoxy-p-tropoquinone was accomplished.

Durch Verwendung der Oxidationsmethode A) (nicht anwendbar auf freie Tropolonderivate) lassen sich die Z‐Alkoxy‐S‐hydroxytropone (I) und (VI) in guter bis sehr guter Ausb. in die . Mono‐ und Diacetale von Tropochinonen überführen.

Ce(IV) oxidizes the tropone (Ia) in absolute methanol to give predominantly C ‐Ccoupling products [(11), (V), and (VI), the bis‐monoacetal of the hitherto unknown bisquinone (VII)], whereas no dimeric products are obtainable from (Ib) by Ce(IV) or TKNOJ), oxidation.