Syntheses of heterocyclic compounds. Part XXIX. Substituted 2,3-dihydro-1H-1,5-benzodiazepines

Abstract

1,5-Benzodiazepine-2-spirocycloalkanes [as (6)] are made in a one-step condensation from o-phenylenediamine and cyclic ketones in cold ethanol in the presence of boron trifluoride–ether complex. The method is also applicable to acyclic ketones. The diazepines can also be prepared from the monohydrochloride of the base with a liquid ketone. Acylation, hydrolysis, reduction, and oxidation of some of these novel diazepines have been studied.