The Pechmann condensation of phenolic fluorenes with ethyl acetoacetate afforded indene-fused 4-methylcoumarins. In addition to the expected indeno[1,2-g]coumarin, a skeletal rearranged compound was obtained as a concomitant product when 9,9-dimethyl-9H-fluorene-2,7-diol was utilized as the substrate. X-ray crystallography was used to identify the structures of the isomers. Photochemical and photophysical studies indicated that compared with the non-rearranged products, the skeletal rearranged isomers have red shifted absorption maxima and much higher fluorescence quantum yields. A mechanism involving two competitive pathways for the simultaneous production of isomers was proposed.

酚芴与乙酰乙酸乙酯的Pechmann缩合反应得到茚-稠合的4-甲基香豆素。当将9,9-二甲基-9 H-芴-2,7-二醇用作底物时，除了预期的茚并[1,2- g ]香豆素以外，还获得了骨架重排化合物。X射线晶体学用于鉴定异构体的结构。光化学和光物理研究表明，与非重排产物相比，骨架重排异构体具有最大吸收红移和更高的荧光量子产率。提出了同时涉及异构体生产的两个竞争途径的机制。