Synthesis of Azulenequinones Fused with Thiophene and Furan.

Abstract

Synthesis of Azulenequinones Fused with Thiophene and Furan. -The bromination of 1,5-and 1,7-azulenequinones (I), (IV) and (VII) fused with thiophene or furan ring is studied. After hydrolytic work-up azulenediones are isolated as the products. -(MATSUO, H.; FUJIMORI*, K.; OHTA, A.; KAKEHI, A.; YASUNAMI, M.; NOZOE, T.; Heterocycles 61 (2003) Special Issue, 271-279; Dep. Chem., Fac. Sci., Shinshu Univ., Asahi, Matsumoto 390, Japan; Eng.) -Mais 17-095

Benz[a]azulenequinones: Reaction of Benz[a]azulenes with Pyridinium Hydrobromide Perbromide

“…As a simpler method, Nozoe, Wakabayashi, and their co-workers demonstrated the reaction of parent azulene with bromine (Br 2 ) in aqueous tetrahydrofuran (THF) to produce 1,5-and 1,7-azulenequinones as a mixture [6]. As the condensed derivatives, Fujimori, Yasunami, Nozoe et al reported azulenequinones condensed with thiophene and furan, respectively, prepared by reacting the corresponding azulenothiophene and furan with Br 2 in aqueous THF [7].…”

“…As a simpler method, Nozoe, W bayashi, and their co-workers demonstrated the reaction of parent azulene with brom (Br2) in aqueous tetrahydrofuran (THF) to produce 1,5-and 1,7-azulenequinones as a ture [6]. As the condensed derivatives, Fujimori, Yasunami, Nozoe et al reported azu equinones condensed with thiophene and furan, respectively, prepared by reacting corresponding azulenothiophene and furan with Br2 in aqueous THF [7]. All the synthetic methods described above are useful for the preparation of azulenequinones, but these methods require a multi-step reaction or the use of a toxic reagent (i.e., Br 2 ) that is difficult to handle.…”