IT is an interesting fact that neitherjpentalene (1), nor heptalene (2), nor any derivatives of them have been definitely reported as being synthesized 1 or found to occur naturally. Azulene (3 ...

Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan ...

Department of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China ...