Mono-, bis-, tris-, and tetrakis(1-azulenylethynyl)benzene and mono- and bis(1-azulenylethynyl)thiophene derivatives 5-10 have been prepared by Pd-catalyzed alkynylation of ethynyl arenes with 1-iodoazulene derivative or the 1-ethynylazulene derivative with tetraiodobenzene and iodothiophenes under Sonogashira-Hagihara conditions. Compounds 5-10 reacted with tetracyanoethylene in a [2+2] cycloaddition reaction to afford the corresponding 1,1,4,4,-tetracyano-2-(5-isopropyl-3-methoxycarbonyl-1-azulenyl)-3-butadienyl chromophores 12-16 in excellent yields, except for the reaction of the tetrakis(1-azulenylethynyl)benzene derivative. 1,1,4,4,-Tetracyano-2,3-bis(1-azulenyl)butadiene (17) was also prepared by the similar reaction of bis(1-azulenyl)acetylene (11) with tetracyanoethylene (TCNE). The redox behavior of novel azulene derivatives 12-17 was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed multistep electrochemical reduction properties. Moreover, a significant color change was observed by visible spectroscopy under electrochemical reduction conditions.

We describe the synthesis and properties of azulene‐substituted 1,1,4,4‐tetracyanobutadienes (AzTCBDs) and heteroazulenyl TCBDs. TCBD derivatives were prepared in good to excellent yields through reaction of the corresponding 1‐ethynylazulenes with tetracyanoethylene (TCNE). In contrast, the reaction between propargyl alcohols and the 1‐azulenyl group in TCNE generated 2‐aminofuran derivatives, which were transformed into 6‐aminofulvenes with a 1‐azulenyl substituent upon treatment with several amines. The optical and electrochemical properties of the AzTCBDs were clarified by UV/Vis and voltammetry. The AzTCBD derivatives exhibited electrochromism, showing a multi‐step color change under electrochemical redox conditions. The multistage redox properties of AzTCBDs could be useful for the development of novel organic electronic materials.

The high expression of CD40/CD40L can be used as a biomarker for better prognoses in patients with gliomas. Immunotherapy using FGK45 significantly prolonged survival and represents a potential therapeutic strategy for gliomas including glioma-initiating cells.

Synthesis of 2-aminofuran derivatives with azulene or N,N-dimethylanilino substituent was established by the formal [2 + 2] cycloaddition-retroelectrocyclization of 3-(1-azulenyl or N,N-dimethylanilino)-2-propyn-1-ols with tetracyanoethylene, followed by the intramolecular nucleophilic addition to the initially formed tetracyanobutadiene moiety of the internal hydroxyl group that come from 2-propyn-1-ol. The reaction proceeds under mild conditions with short reaction period. The products of the reaction are readily available with simple purification procedure. 2-Aminofuran derivatives obtained by this reaction were revealed to be convertible to 6-aminofulvene derivatives with the treatment of various amines. The structure of 2-aminofuran and 6-aminopentafulvene with N,N-dimethylanilino substituent was confirmed by single crystal X-ray structural analysis.