Organic Chemistry of Explosives

5-Membered rings – 2N 303

NN

O

CON 3

N

OO

N 3 OC N

Na 2 WO 4

dioxane (aq),

80 °C

KMnO 4 , HCl (aq)

acetone

90 % H 2 O 2 , H 2 SO 4

62

64 63

(DDF)

N

N

O

NN

O

NO 2

N

OO

O 2 NN

N

N

O

NN

O

NH 2

N

OO

H 2 NN

N

N

O

NN

O

H 2 N CON 3

61

O

Figure 7.25

A high-energy material has recently been reported in the form of 4,4’-dinitro-3,3’-

diazenofuroxan (DDF) (64).^37 This material was synthesized from the oxidative coupling

of 4-amino-3-(azidocarbonyl)furoxan (61), followed by Curtius rearrangement and oxidation

of the resulting amino groups to nitro groups. The experimental detonation velocity of DDF

(64) reaches 10000 m/s at a crystal density of 2.02 g/cm^3. The high density of DDF is due to

very efficient crystal packing.

7.3.7 Benzofuroxans

Benzofuroxans are far more stable than simple furoxans and are more favourable for practical

applications. There are two standard methods for the synthesis of the benzofuroxan skeleton: (1)

treating anortho-nitroarylamine with a mild oxidant like sodium hypochlorite and (2) either

heating or irradiating anortho-nitroarylazide with UV light. Benzofuroxan itself has also

been prepared by treating 1,2-benzoquinone dioxime with alkaline hypochlorite or alkaline

potassium ferricyanide solution.^38

NO 2

O 2 N NO 2

N 3

N 3

65

N 3 N

N O

N O

N

N

O

N

O

66

O

O

heat, -N 2

Figure 7.26

Benzenetrifuroxan (66) is a powerful explosive which was first synthesised by Turek^39 in

1931 by heating 1,3,5-triazido-2,4,6-trinitrobenzene (65) to its melting point (131◦C); the

latter prepared from the reaction of 1,3,5-trichloro-2,4,6-trinitrobenzene with sodium azide in

aqueous ethanol.