Treatment of 1H-1, 2-benzodiazepines having an electron-withdrawing group such as methoxycarbonyl or cyano in the 3-position with lead tetraacetate resulted in the formation of the corresponding 5-acetoxy-5H-1, 2-benzodiazepines, which are the first reported examples of 5H-1, 2-benzodiazepines. The 5H-diazepines, on treatment with base, underwent tautomerization to the 1H-isomers, and on photolysis gave 3-acetoxyindole via the tricyclic valence isomers. Furthermore, treatment of a 5H-diazepine with methanol or acetic acid gave the corresponding 4-methoxy- or 4-acetoxy-4, 5-dihydro-1H-1, 2-benzodiazepine, respectively, by 1, 4-addition of the reagent.
对在3位含有电子吸引基团(如甲氧基羧基或
氰基)的1H-1,2-苯二氮卓类化合物进行四
乙酸铅处理,形成了相应的5-乙氧基-5H-1,2-苯二氮卓,这些是首次报道的5H-1,2-苯二氮卓的例子。这些5H-二
氮杂茂在与碱反应时发生互变异构化,转化为1H-异构体,并在光解作用下通过
三环价异构体生成3-乙氧基
吲哚。此外,将5H-二
氮杂茂与
甲醇或
醋酸处理,分别通过试剂的1,4-加成反应生成相应的4-甲氧基或4-乙氧基-4,5-二氢-1H-1,2-苯二氮卓。