Synthesis of dipyrrolo-diazepine derivatives via intramolecular alkyne cyclization

A regioselective approach was developed for the synthesis of dipyrrolo-diazepine derivatives. The synthetic route to dipyrrolo-diazepines first involves the synthesis of dipyrromethanes, followed by reaction of propargyl bromide in the presence of NaH to attach one alkyne functionality to the pyrrole nitrogen atom. Intramolecular heterocyclization with NaH in DMF between the alkyne functionality and pyrrole nitrogen atom gave the desired structures in good yields. (C) 2018 Elsevier Ltd. All rights reserved.