Bromination of 11-acetoxydibenzo[a,e]cycloocten-5(6H)-one (6) gave the 6-bromo derivative (8), which on further bromination gave a hydrogen bromide adduct (12 or 13) of 6,6,12-tribromodibenzo[a,e]cyclooctene-5,11(6H,12H)-dione (14). Treatment of this adduct with aqueous-ethanolic ammonia followed by sublimation gave 11-oxoindeno[1,2-c]isocoumarin (4), not dibenzo[a,e]cyclooctene-5,6,11(12H)-trione (3) as earlier suggested. The conversion of 12 or 13 to 4 has been shown to involve the formation of 3-bromo-2-(o-carboethoxyphenyl)indone (17), which gave 4 and ethyl bromide on being heated at 180°. Oxidation of dibenzo[a,e]cyclooctene-5,11(6H,12H)-dione with selenium dioxide gave a bimolecular product 25 considered to be derived by loss of carbon monoxide from the dimer of dibenzo[b,ƒ]pentalene-5,10-dione (27), a selenium-containing product, 28, and the hydrate 29 of 3.
对11-乙酰氧基二苯并[a,e]环
辛烯-5(6H)-酮(6)进行
溴化反应得到6-
溴衍
生物(8),进一步
溴化得到6,6,12-三
溴二苯并[a,e]环
辛烯-5,11(6H,12H)-二酮(14)的
氢溴酸加合物(12或13)。将该加合物经过
水乙醇氨处理后升华,得到11-氧代
吲哚并[1,2-c]异
香豆素(4),而不是先前提出的二苯并[a,e]环
辛烯-5,6,11(12H)-三酮(3)。已经证明将12或13转化为4涉及3-溴-2-(o-羧
乙酸苯基)
吲哚酮(17)的形成,该化合物在180℃加热时生成4和
溴乙烷。使用
二氧化硒对二苯并[a,e]环
辛烯-5,11(6H,12H)-二酮进行氧化反应,得到一个双分子产物25,被认为是由二苯并[b,f]五环烯-5,10-二酮(27)的二聚体失去一分子
一氧化碳,得到含
硒产物28和3的
水合物29。