Synthesis of 1,4-Benzodiazepine-2,5-diones by Base Promoted Ring Expansion of 3-Aminoquinoline-2,4-diones
2017
Křemen, Filip | Gazvoda, Martin | Kafka, Stanislav | Proisl, Karel | Srholcová, Anna | Klásek, Antonín | Urankar, Damijana | Košmrlj, J. (Janez)
An unprecedented reactivity of 3-aminoquinoline-2,4-diones is reported. Under basic conditions, these compounds undergo molecular rearrangement to furnish 1,4-benzodiazepine-2,5-diones. The transformations take place under mild reaction conditions by using 1,1,3,3-tetramethylguanidine, NaOEt, or benzyltrimethylammonium hydroxide as a base. A proposed mechanism of the rearrangement and the conformational equilibrium of 1,4-benzodiazepine-2,5-dione rings are discussed.
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