Synthesis and X-ray Crystal Structure of 1,3,3-Trinitroazetidine

Article abstract of DOI:10.1021/jo00296a066

1,3,3-Trinitroazetidine (1) was synthesized and its structure elucidated by X-ray crystallography.Reaction of 1-tert-butyl-3-((methylsulfonyl)oxy)azetidine (3a) with sodium nitrite gave 1-tert-butyl-3-nitroazetidine (4a), which was converted to 1-tert-butyl-3,3-dinitroazetidine (5a) by oxidative nitration.Nitrolysis of 5a with acetyl nitrate gave 1. 1-Benzhydryl-3,3-dinitroazetidine (5b) did not undergo a similar nitrolysis.Single-crystal X-ray analysis of 1 showed that the ring is puckered, with a dihedral angle of 13.6(5) deg between the C-C-C and C-N-C planes, and that the nitramino group exhibits an unusually high (39.4 deg) out-of-plane deformation.A structural optimization with MNDO reproduced the ring pucker and the nitramino bend to within 5 deg.The large bend at the ring nitrogen atom indicates sp³ rather than sp² for its hybridization.However, the N-N bond length, 1.351(6) Angstroem, falls in the normal range for planar (sp²) nitramines and is ca. 0.1 Angstroem shorter than N-N bonds previously observed in bent nitramines.