Structural Engineering of Furazanopyrazine Scaffolds with Flexible Biogenic Amines and Nitramine Moieties for Fused Energetic Melt-Castable Materials

Furazanopyrazine-based energetic compounds were developed through a substitution–nitration strategy combining flexible biogenic amine side chains with nitramine modification. Structural and thermal analyses revealed that side-chain flexibility effectively tunes crystal packing and phase behavior. Among compounds I–VII·H₂O, compound II exhibited the most favorable melt-cast characteristics, with a melting point of 89 °C, competitive detonation performance, and acceptable sensitivities. These results offer a useful design strategy for fused-ring melt-cast energetic materials.