Heterocyclic nitramines derived from Mannich reactions

8 HETEROCYCLIC NITRAMINES DERIVED FROM MANNICH REACTIONS 

Hybrid compounds containing heterocyclic nitramine and em-dinitro functionality represent a class of high performance energetic materials. Such compounds frequently exhibit higher heats of formation, crystal density, detonation velocity and pressure, and better oxygen balance compared to analogous aromatic compounds. 

The Mannich reaction has been used to synthesize numerous heterocyclic nitramine explosives. Adolph and Cichra prepared a number of A-heterocycles containing ferf-butyl A-blocking groups. The nitrolysis of these f-butyl groups provides the corresponding A-nitro derivatives in excellent yields (Section 5.6.2.2). Some of the nitramine products from these reactions are powerful, energetic explosives with attractive properties. 

5-Pentanitropiperidine (91) is prepared from the condensation of 2,2-dinitro-l,3-propanediol (89) with formaldehyde and f-butylamine under slightly acidic conditions, followed by nitrolysis of the f-butyl group of the resulting piperidine (90) with mixed acid or absolute nitric acid.  

5-Tetranitrohexahydropyrimidine (DNNC) (94) has been synthesized from the nitrolysis of the A(iV -di-fert-butylpyrimidine (93). Levins and co-workers reported the synthesis of DNNC (94) from the nitrolysis of the analogous A. V -di-wo-propylpyrimidine (92). DNNC is a high performance explosive with a detonation velocity of 8730 m/s, impact sensitivity lower than RDX and a very favourable oxygen balance. DNNC has been suggested for use as an oxidizer in propellant compositions. This is also considered as an excellent oxidant for pyrotechnic compositions.  

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