A facile and concise route toward the synthesis of novel imidazo-tetrazolodiazepinones via post-condensation modifications of the Ugi-azide adduct

This Letter describes novel methodology for the rapid assembly of unprecedented and likely biologically relevant imidazo-tetrazolodiazepinones. The product of a TMSN3-Ugi multi-component reaction is treated with an excess of isocyanate to generate 1,5-disubstituted tetrazolo-hydantoins functionalized with an internal-masked amino nucleophile previously introduced by the isocyanide input. Final products are obtained in good overall yields after microwave irradiation of the tetrazolo-hydantoin in acidic media. This methodology allows the production of complex polycyclic compounds in a mere three synthetic steps. (C) 2015 Published by Elsevier Ltd.