Synthesis and characterization of 5-amino-1,3,6-trinitro-1H-benzo[d]imidazol-2(3H)-one as an energetic material

Two synthetic routes for the preparation of 5-amino-1,3,6-trinitro-1H-benzo[d]imidazol-2(3H)-one (2) as an energetic material have been revealed. Direct nitration of 5-amino-1H-benzo[d]imidazol-2(3H)-one (1) gave the trinitrated compound 2 in a poor yield of 11%; and similarly using 1 as starting material, 2 was obtained by N-protected reaction, nitration, deprotection and again nitration reaction with an overall-yield of 48%. All structures of 2 and relevant compounds were determined by IR, ¹H NMR, ¹³C NMR spectroscopy, MS and elemental analysis. Theoretical calculations showed that the detonation properties of compound 2 (D = 7.78 km s⁻¹, P = 27.05 GPa) were satisfactory, compared with 2,4,6-trinitrotoluene (TNT, D = 7.21 km s⁻¹, P = 22.49 GPa).