Reactions of 3-Isopropenyl- and 3-Acetyltropolone with Quarternary Ammonium Tribromides
作者:Yoichiro Matsunaga、Kimiaki Imafuku
DOI:10.1246/bcsj.65.295
日期:1992.1
Treatments of 3-isopropenyltropolone with quarternary ammonium tribromides in tetrahydrofuran afforded 3-methyl-8H-cyclohepta[b]furan-8-one. The reactions in methanol–dichloromethane gave 7-bromo-3-methyl-8H-cyclohepta[b]furan-8-one. Bromination of 3-acetyltropolone with the tribromides in tetrahydrofuran produced 3-(bromoacetyl)tropolone, while the reaction in the methanolic solvent gave 7-bromo- and 5,7-dibromo-substituted 3-acetyltropolones. The brominations of 4′-hydroxyacetophenone were also carried out.
3-(1-Phenylvinyl)tropolone (3b) was prepared by the hydrolysis of cycloadducts of 6-methyl-6-phenylfulvene with dichloroketene. 3-Isopropenyltropolone and 3b were treated with 2,3-dichloro-5,6-dicyano-p-benzoquinone or performic acid to give 3-methyl- and 3-phenyl-8H-cyclohepta[b]furan-8-one, respectively. Reaction of 3b with hydrazoic acid afforded an unexpected 3-acetyltropolone.