New Routes to the Azulene System

✍ Scribed by Prof. Dr. Horst Prinzbach; Dipl.-Chem. Hans-Jürgen Herr

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 179 KB
• Volume: 11
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.197201351

✦ Synopsis

4 ) (14.9g, 50mmol) is refluxed with dimethyl acetylenedicarboxylate (7.8 g, 55 mmol) in anhydrous benzene (100 ml) for 4 h. After removal of the benzene the residue [ ( S ) / ( 6) ] is dissolved in acetone (1.7 liter) and irradiated in a Pyrex vessel ( O T ) with the light from a Hanau T Q 2024 2OOO-W lamp until reaction is complete (6 h, NMR monitoring). The acetone is distilled off and conc. HCl (20 ml) is added to a solution of the residue in CH,CI, (2 liter). After 15 min the reaction mixture is neutralized by addition of sodium hydrogencarbonate solution, and the organic phase is dried and chromatographed with benzene on AI,O, [basic, deactivated with 6% H,O (Woelm)]. The deep red zone that is first eluted gives 8.2g of (8) [39% based on ( 4 ) ] on recrystallization from ether.