Organic Chemistry of Explosives

6 Energetic Compounds 2: Nitramines and Their Derivatives

In Chapter 5 we discussed the methods used to incorporateN-nitro functionality into com-

pounds in addition to the synthesis of the heterocyclic nitramine explosives RDX and HMX.

The high performance of such heterocyclic nitramines has directed considerable resources to-

wards the synthesis of compounds containing strained or caged skeletons in conjunction with

N-nitro functionality. These compounds derive their energy release on detonation from both

the release of molecular strain and the combustion of the carbon skeleton. Some nitramine

compounds contain heterocyclic structures with little to no molecular strain. Even so, such

skeletons often lead to an increase in crystal density relative to the open chain compounds

and this usually results in higher explosive performance. A common feature of explosives

containingN-nitro functionality is their higher performance compared to standardC-nitro

explosives like TNT. Compounds containing strained or caged skeletons in conjunction with

N-nitro functionality are some of the most powerful explosives available.

6.1 Cyclopropanes

NHAc

NHAcAcHN

NHNO 2

O 2 NHN NHNO 2

(^12)

Ac 2 O, HNO 3 or
TFAA, HNO 3

NH 4 OH

H+

Figure 6.1

1,2,3-Tris(nitramino)cyclopropane (2) has been synthesized via the nitration of 1,2,3-

tris(acetamido)cyclopropane (1) with acetic anhydride–nitric acid, followed by ammonoly-

sis of the resulting secondary nitramide and subsequent acidification of the ammonium

salt.^1 This strategy is a common route to primary nitramines (see Section 5.10). 1,2,3-

Tris(nitramino)cyclopropane has a favourable oxygen balance and is predicted to exhibit high

performance.^1

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6 Energetic Compounds 2: Nitramines and Their Derivatives