Abstract
An efficient cyclization between nitro-substituted benzoic acids and nitro-substituted benzohydrazides affords 1,3,4-oxadiazoles. Facile synthesis and a broad substrate scope produce a range of compounds, some of them with potential as high-energy compounds. Heats of formation (H-f) and densities () were calculated, and heats of decomposition (H-d) and combustion (H-c) were determined experimentally. The densities of seven of the synthesized compounds were determined by gas pycnometry, and the respective values of detonation velocity (V-D), detonation pressure (P-D) and specific impulse (I-SP) were calculated using the EXPLO5 program. An X-ray structure of 2-(2,4-dinitrophenyl)-5-(3,5-dinitrophenyl)-1,3,4-oxadiazole (4n) revealed the non-planarity of the molecule and afforded a crystal density of 1.698 (at 120 K), close to the pycnometric value of 1.64 at room temperature.