T. Nakadate, T. Morita, K. Takase
Jun 5, 1977
Citations
0
Influential Citations
3
Citations
Journal
Chemistry Letters
Abstract
Diethyl 4-phenylethynylazulene-1,3-dicarboxylate (3) undergoes a Friedel–Crafts-type ring closure on treatment with polyphosphoric acid to give the cyclopent[cd]azulene derivative (5). In a similar manner, diethyl 4-styrylazulene-1,3-dicarboxylate (4) gives the benz[cd]azulene derivative (8) and the cyclopent[cd]azulene derivative (9). Some chemical properties of 5 are described.