280 Nitramines and Their Derivatives
NNOHHOHOCHOCHO
86N
H.HClH
NNN NNO OHHHHNNNNNNO ONO 2
117
(HHTDD)NO 2O 2 N NO^2 NO 2O 2 N2 eq CO(NH 2 ) 2 ,
conc. HCl
82 %- HNO 3 , Ac 2 O
- NO 2 BF 4
CH 3 CN, 73 %
116
OHFigure 6.32NNNNNNO ONO 2NO 2
118HHHHNNNNNNO ONO (^2) NO
2
NO 2
119
H
H
O 2 N
N
N
N
NN
N
O O
NO 2
NO 2
NO 2
NO 2
121
H
O 2 N
N
N
N
NN
N
O O
NO (^2) NO
2
NO 2
120
H H
O 2 N
Figure 6.33
Boyer and co-workers^47 reported the synthesis of 2,6-dioxo-1,3,4,5,7,8-hexanitrodeca-
hydro-1H,5H-diimidazo[4,5-b:4′,5′-e]pyrazine (117) (HHTDD). The hydrochloride salt of
the tricycle (116) was synthesized from the reaction of 1,4-diformyl-2,3,5,6-tetrahydroxypi-
perazine (86) with a solution of urea in concentrated hydrochloric acid, followed by recrystal-
lization of the product from methanol. The nitration of the tricycle (116) was studied in some
detail. The low temperature nitration of (116) with pure nitric acid leads to the nitration of the
piperazine nitrogens only and the isolation of the 4,8-dinitro derivative (118) in 28 % yield.
Nitration of the urea nitrogens proves more difficult with (116) yielding a mixture of tetranitro
derivatives, (119) and (120), on nitration with nitric acid in acetic anhydride. Further treatment
of this mixture with excess nitric acid in acetic or trifluoroacetic anhydrides for a prolonged
period yields the pentanitro derivative (121). Treatment of (119), (120) or (121) with nitronium
tetrafluoroborate in acetonitrile produces HHTDD (117). The direct nitration of (116) with a
solution of 20 % dinitrogen pentoxide in nitric acid gives HHTDD (117) in 74 % crude yield.
HHTDD (117) has an excellent oxygen balance and exhibits high performance (calculated
VOD∼9700 m/s, 2.07 g/cm^3 ). However, the hydrolytic stability of HHTDD is poor and so
limits its value as a practical explosive.
N
H
H
N
N
H
H
N
H
N
N
H
N N
. 4 HCl N
NN
HH
NH
NN
HN N. 2 H 2 O
NO 2
123
NO 2O 2 N NO 2122H HFigure 6.34