Organic Chemistry of Explosives

298 N-Heterocycles

nitro-substituted furazans have excellent oxygen balance and exhibit detonation velocities

close to very powerful military explosives.

H

O

H

O

NH 2

NOH

H 2 N

HON

N

O

N

H 2 N NH 2

NH 2 OH

23

base (aq)

180 °C, pressure

24

(DAF)

Figure 7.9

3,4-Diaminofurazan (DAF) (24) is a starting material for the synthesis of many nitro-

substituted furazans and is readily prepared from the cyclization of 1,2-diaminoglyoxime (23)

in the presence of aqueous base under pressure at 180◦C;^17 the latter prepared from the reaction

of glyoxal,^18 glyoxime,^19 cyanogen^20 or dithiooxamide^21 with hydroxylamine.

N

O O

N NN

O

NN

O O O

NN

H 2 N NO 2 H 2 N NNHNN 2 H 2 N

NN

N NH 2

O

NN

O 2 N NO 2

25

(ANF)

28

(DNF)

26

(DAAzF)

27

(DAAF)

Figure 7.10

N

O

N

H 2 N NH 2

N

O

N

H 2 N NO 2

(^2425)
(ANF)
30 % H 2 O 2 , Na 2 WO 4 ,
(NH 4 ) 2 S 2 O 8 , H 2 SO 4
70 %
Figure 7.11
The oxidation of DAF (24) with hydrogen peroxide can yield 3-amino-4-nitrofurazan (ANF)
(25), 4,4′-diamino-3,3′-azofurazan (DAAzF) (26), or 4,4′-diamino-3,3′-azoxyfurazan (DAAF)
(27) depending on the conditions employed.^22 The most convenient route to ANF (25) involves
treating DAF (24) with a mixture of 30 % aqueous hydrogen peroxide, sodium tungstate and
ammonium persulfate in concentrated sulfuric acid.^23 ,^24 Both of the amino groups of DAF
(24) are oxidized to give 3,4-dinitrofurazan (DNF) (28) if 30 % hydrogen peroxide is replaced
by 90 % hydrogen peroxide.^24 DNF (28) is a very powerful explosive with a positive oxygen
balance but it is too reactive and shock sensitive to be considered for use as a practical explosive.
N
OO
N
2 N NH
NN
NH 2
26
(DAAzF)
N 30 % H 2 O 2 , Na 2 WO 4 ,
(NH 4 ) 2 S 2 O 8 , H 2 SO 4
25 % NN
2 N NH
N
OO
N
NO 2
29
N
O
Figure 7.12
DAAzF (26) can be oxidized with a mixture of 30 % aqueous hydrogen perox-
ide, sodium tungstate and ammonium persulfate in concentrated sulfuric acid to yield