Organic Chemistry of Explosives

Nitrative cleavage of other nitrogen bonds 223

N

N

N

CF 3

NOON

NO

F 3 C CF 3

N

N

N

CF 3

O 2 N NO 2

NO 2

F 3 C CF 3

HNO 3 , TFAA

80 %

(^122123)
Figure 5.57
Krimmel and co-workers^10 have reported the synthesis of 2,4,6-tris(trifluoromethyl)-1,3,5-
trinitro-1,3,5-triazacyclohexane (123) from the nitrolysis of the nitrosamine (122).

5.7 Nitrative cleavage of other nitrogen bonds

N COR'

R

R

R

NNO 2

R

N COR'

O 2 N

R

acyl cleavage

(nitramide) (nitramine)

R–N bond cleavage

Figure 5.58

In the previous section we discussed the nitrolysis ofN, N-dialkylamides as a common route

to secondary nitramines, especially when the parent amine is too basic to allow for direct

N-nitration. This route is usually very successful, but it has shortfalls, including the potential

for nitrolysis of one of the C–N bonds other than the acyl linkage. This leads to a reduced

yield and lower product purity. The by-product of amide nitrolysis is an acyl nitrate which also

poses safety and disposal problems on a large scale. This problem is encountered during the

synthesis of the high explosive HMX via the nitrolysis of DADN (Section 5.15.2).^119 Problems

with amide nitrolysis are partly attributed to the reduction of electron density on nitrogen due

to the electron-withdrawing acyl group. Consequently, some acyl derivatives of polycyclic

polyamines are inert or extremely sluggish to nitrolysis.

The nitrolysis oftert-butyl substituted amines with dinitrogen pentoxide in nitric acid

solves many of these problems. However, these substrates are not always accessible via the

usual condensation routes. The acidic reagents frequently used for these nitrolysis reactions

are not always suitable for substrates with acid-sensitive or easily oxidized functionality.

N

NN

(CH 3 ) 3 Sn Sn(CH 3 ) 3

(CH 3 ) 3 Sn

N

NN

O 2 N NO 2

O 2 N

124 125

NO 2 BF 4 , CH 3 CN

Figure 5.59

Problems associated with amide nitrolysis have been approached in a very logical way.

One strategy is to make the nitrogen atom more susceptible to electrophilic attack and hence

facilitate nitrolysis. An electron-donating group on nitrogen would achieve this. Accordingly,

the nitrolysis of stannylamines like (124) have been reported.^98 Nitrative cleavage of a N–P