文摘
Several azulene-substituted thioketones, 1-thiobenzoylazulene (1a) and di(1-azulenyl) thioketone (2a)and their derivatives (1b and 2b-d) with alkyl substituents on each azulene ring, were prepared andtheir intramolecular pericyclization reaction was examined. The thioketones with a 3-alkyl substituenton each azulene ring exhibited the presumed pericyclization reaction under thermal and acid-catalyzedconditions, although the cases of the 1-azulenyl thioketones without the 3-alkyl substituents afforded acomplex mixture under similar conditions. The intramolecular reaction following the intramolecularhydrogen transfer afforded the products 13b, 14b, and 14c. The products 13b and 14b were convertedinto the corresponding cations 18+ and 19+, which have structural similarity with that of the phenalenylcation. These cations exhibited the expected two-step reduction waves upon CV, although the ESR analysisrevealed that the neutral radical state did not have the presumed high stability.