Improved Synthesis of an Energetic Material, 1,3,3-Trinitroazetidine Exploiting 1-Azabicyclo[1.1.0]butane

Expeditious synthesis of 1-nitroso-3-nitroazetidine (6), a useful key intermediate for the synthesis of 1,3,3-trinitroazetidine (4), was investigated by using 1-azabicyclo[1.1.0]butane(3) and NaNO 2 in the presence of some acids.The most efficient method was achieved in 26% yield by treatment of 3 with NaNO 2 in the presence of H 2 SO 4 .Conversion of 6 into 4 was also carried out.1-Azabicyclo[1.1.0]butaneshave been characterized to be highly strained bicyclic structures. 1 Since the first report of the synthesis and reactivity of these compounds, little attention has been paid to the unusual ring system. 2 Specifically, the synthetic utility of 1-azabicyclo[1.1.0]butane(3), which must be expected to be useful for the preparation of various 1,3-disubstituted and 3-monosubstituted azetidines, has scarcely reported because of its synthetic difficulty due to the remarkably strained structure. 1-3In the meantime, the usefulness of the compound (3) and its related compound as a key intermediate in the synthesis of a particular compound, 1,3,3-trinitroazetidine (TNAZ, 4) was reported. 4TNAZ (4) has been noteworthy from the viewpoint of a new important energetic material involving numerous applications to the explosive and propellant technology. 5Hence, efficient and environmentally benign methods for the large-scale synthesis of TNAZ (4) have been required. 6Although there have been several reports for the synthesis of TNAZ (4), its preparation exploiting a highly strained molecule (3) seems to be a quite elegant method. 4,7However, the earlier methods using 3 resulted in the very poor yields of TNAZ (4) or of its synthetic intermediate. 4Recently, we have developed a new efficient procedure for the synthesis of