Organic Chemistry of Explosives

304 N-Heterocycles

Cl

O 2 N NO 2

NO 2

67

N 3

O 2 N NO 2

NO 2

70

NaN 3

N

O

N

O

N

O

N

O

NO 2

O 2 N

NH 2 OH, NaOEt H 2 SO 4 , HNO 3

Heat

68 69

(DNBF)

Figure 7.27

4,6-Dinitrobenzofuroxan (DNBF) (68) has been prepared from the nitration of benzofuroxan

(69) with mixed acid,^40 and by treating picryl chloride (67) with sodium azide and heating the

resulting picryl azide (70) in an inert solvent.^41 ,^42

N

O

N

O

NO 2

N

H

O

O

R = N or O nucleophile,

M = alkali metal

71

M+

R

Figure 7.28

DNBF (68) readily forms stable Meisenheimer complexes (71) with numerous oxygen

and nitrogen nucleophiles and some of these are primary explosives with useful initiating

properties.^42 –^46

N

72

O 2 N NO 2

Cl N

73

O 2 N NO 2

N 3 N N

O

O 2 N N

O

74

NaN 3 , EtOH (aq) PhCH 3 , heat

Figure 7.29

The fused pyridine-furoxan (74) has been synthesized from 3,5-dinitro-2-chloropyridine

(72) via the azide (73).^47

NH 2

NO 2

NH 2

O 2 N

NO 2

76

N

O

N

O

NO 2

77

(ADNBF)

NH 2

H 2 SO 4 , HNO 3 NaN 3 , AcOH O 2 N

75

NO 2

NO 2

Figure 7.30

The introduction of amino functionality adjacent to a nitro group in a benzo-

furoxan is known to reduce impact sensitivity and increase thermal stability. Accordingly,