Synthesis and Redox Behavior of 1‐Azulenyl Sulfides and Efficient Synthesis of 1,1′‐Biazulenes

Abstract

The reaction of azulenes with several sulfoxides in the presence of acid anhydrides to afford the corresponding 1-azulenylsulfonium and 1,3-azulenediyldisulfonium ions is reported. The subsequent conversion of these ions in high yields into 1-azulenyl methyl and phenyl sulfides and 1,3-bis(methyl-and phenylthio)azulenes through treatment with diethylamine is also described. Reaction of the 1-azulenyl sulfides with MCPBA afforded 1-azulenyl sulfoxides, which were then efficiently transformed into 1,1Ј-biazulene deriva-

Synthesis and Reactivity of 3-Methylsulfinyl-2H-cyclohepta[b]furan-2-ones

“…These sulfonium compounds (3a,b) dissolved in i PrOH were treated with Et 2 NH or Et 3 N at 100 °C to give 4a and 4b, respectively. 7 These sulfides (4a,b) were easily oxidized with m-CPBA to give 3-methylsulfinyl-2H-cyclohepta[b]furan-2-ones (5a,b) as yellow crystals. Furthermore 5a and 5b were oxidized with anther m-CPBA to afford 6a and 6b within 2h, respectively.…”

Synthesis of 1‐Heteroaryl‐ and 1,3‐Bis(heteroaryl)azulenes: Electrophilic Heteroarylation of Azulenes with the Triflates of N‐Containing Heteroarenes

“…The pyridylation of 1,1Ј-biazulene (6) was also established by the procedure, similar to the other azulene derivatives. The reaction of 6, which could be prepared by the procedure reported by us, previously, [21] with pyridine in the presence of Tf 2 O gave 7 in 85 % yield. Product 7 was transformed into the desired compound 8 by treatment with KOH in EtOH at room temperature in 95 % yield (Scheme 2).…”

Synthesis of Azulenopyridinones through Palladium‐Catalyzed Oxidative [4+2] Cyclization Reactions of N‐Methoxyazulene‐1‐ and 2‐carboxamides with Alkynes

“…[8e,12] Additionally, 3 a reacted with DMSO in the presence of trifluoroacetic anhydride followed by diethyl amine to give methylsulfenylated azulenopyridinone (7) in 86% yield (b). [13] Formylated azulenopyridinone (8) was generated from 3 a and POCl 3 (c). [14] To our delight, 3 a was converted to the corresponding haloazulenopyridinones (9 a and 9 b) with excellent yields using NBS and NIS (d).…”