Synthesis and biological evaluation of naphthoquinone-fused pyrrole and imidazopyridinedione heterocycles†

Abstract

We have developed an efficient and straightforward synthetic route to obtain naphthoquinone-fused pyrrole derivatives (up to 93% yield) via an intramolecular cyclization of 2-(arylethynyl)naphthalene-1,4-dione derivatives with NH₄OAc in methanol at ambient temperature. Furthermore, imidazopyridinedione derivatives were synthesized via coupling between 2-bromonaphthalene-1,4-dione and 2-amino pyridine through condensation and rearrangement under neat conditions in the presence of a catalytic amount of AcOH. A series of functionalized pyrrolonaphthoquinone and imidazopyridinedione derivatives were synthesized in high yields. Additionally, one of the synthesized pyrrolonaphthoquinones was selected as the model substrate for evaluating cytotoxicity and antimicrobial activity against both Gram-positive and Gram-negative biofilm bacteria.