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A simple route to 2,3-benzodiazepines from substituted indenes
Ekaterina S Tarasova1, Olga V Shurupova1, Sergey A Rzhevskiy1
1A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow, 119991, Russia. aasachenko@ips.ac.ru.
Abstract:
Herein, we present a two-step approach for synthesizing 2,3-benzodiazepines from substituted indenes. This process involves oxidation of indenes to 1,5-diketones followed by their cyclocondensation with hydrazine hydrate. The optimized conditions for a wide range of substituted 2,3-benzodiazepines, including the well-known anxiolytic tofisopam, were investigated. A detailed mechanism for the cyclization of 1,5-diketones with hydrazine hydrate was established using 1H NMR kinetic experiments.
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