N-(2-Fluoro-2,2-dinitroethyl)azoles: a novel assembly of diverse explosophoric building blocks for energetic compound design

Abstract

Although desirable from an energetic materials chemistry perspective, nitroazoles bearing oxygen-rich explosophoric units at a nitrogen atom of the ring are a highly challenging target using current literature approaches. In this paper, we report the first simple two-step protocol to efficiently prepare unprecedented N-(2-fluoro-2,2,-dinitroethyl) derivatives of imidazoles, pyrazoles, triazoles, and tetrazoles. Michael addition of NH-azoles to 1,1-dinitroethene, generated from 1,1,1-trinitroethane, followed by fluorination provides the N-dinitrofluoroethylated nitrogen heterocycles in moderate to good overall yields. The syntheses employ azoles with electron-withdrawing groups, predominantly, the nitro group, and can be extended to other structurally attractive electron-deficient NH-heterocycles.