title: Synthesis and intramolecular pericyclization of 1-azulenyl thioketones.
abstract: 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 and their intramolecular pericyclization reaction was examined. The thioketones with a 3-alkyl substituent on each azulene ring exhibited the presumed pericyclization reaction under thermal and acid-catalyzed conditions, although the cases of the 1-azulenyl thioketones without the 3-alkyl substituents afforded a complex mixture under similar conditions. The intramolecular reaction following the intramolecular hydrogen transfer afforded the products 13b, 14b, and 14c. The products 13b and 14b were converted into the corresponding cations 18(+) and 19(+), which have structural similarity with that of the phenalenyl cation. These cations exhibited the expected two-step reduction waves upon CV, although the ESR analysis revealed that the neutral radical state did not have the presumed high stability.
authors.affiliation: Graduate School of Science and Technology, Hirosaki University, Hirosaki 036-8561, Japan. itsnj@cc.hirosaki-u.ac.jp
authors.forename: Shunji
authors.initials: S
authors.lastname: Ito
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Okujima
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kikuchi
authors.forename: Taku
authors.initials: T
authors.lastname: Shoji
authors.forename: Noboru
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authors.lastname: Morita
authors.forename: Toyonobu
authors.initials: T
authors.lastname: Asao
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Ikoma
authors.forename: Shozo
authors.initials: S
authors.lastname: Tero-Kubota
authors.forename: Jun
authors.initials: J
authors.lastname: Kawakami
authors.forename: Akio
authors.initials: A
authors.lastname: Tajiri