Organic Chemistry of Explosives

5-Membered rings – 3N 309

This is seen during the nitration of PATO (99), which on treatment with a mixture of nitric acid

in acetic anhydride at 40◦C for 30 minutes yields theN-nitro product (106), whereas the same

reaction at 60◦C for 1.5 hours yields theC-nitro product (107).^61 An explosive known as PANT

(109) has been prepared from the reaction of 4-amino-1,2,3-triazole (108) with picryl chloride

followed byC-nitration of the 1,2,3-triazole ring with mixed acid at room temperature.^64

NN

N

H

NH 2

NN

N

H

NH

O 2 N

O 2 N

NO 2

NO 2

109

(PANT)

1. picryl chloride


2. HNO 3 , H 2 SO 4 , 20 °C

108

Figure 7.41

Amino derivatives of 1,2,3- and 1,2,4-triazoles are useful precursors to the corresponding

nitro-substituted triazoles. 3-Amino-1,2,4-triazole (98) undergoes diazotization on reaction

with nitrous acid; the resulting diazonium salt (110) can react with a range of nucleophiles,

including an aqueous solution of sodium nitrite which yields 3-nitro-1,2,4-triazole (111).^65 ,^66

Diazotization of 3,5-diamino-1,2,4-triazole (112), followed by heating with an aqueous solu-

tion of sodium nitrite, yields 3,5-dinitro-1,2,4-triazole (113).^67 ,^68

N

H

N

NH 2

N

N N

N

H

N

H 2 N

H 2 N

N

N

H

N

O 2 N

O 2 N

N

H

N

N 2

N

N

H

N

O 2 N

NO 2

N

N

H

N

NH 2

NaNO 2

98 111

57 % (2 steps)

110

(^112113) 114 (ANTA)
50 % (3 steps)
H 2 SO 4 , NaNO 2
60 °C 2. NH 2 NH 2 .H 2 O,
Heat

1. Convert to
   ammonium salt

H 2 SO 4 , AcOH NaNO 2 (aq), 50 °C

Figure 7.42

Treatment of the ammonium salt of 3,5-dinitro-1,2,4-triazole (113) with hydrazine hydrate

leads to selective reduction of one of the nitro groups to yield 3-amino-5-nitro-1,2,4-triazole

(ANTA) (114), a high performance explosive (calculated VOD∼8460 m/s) possessing thermal

stability (m.p. 238◦C) and an extremely low sensitivity to impact.^68 ANTA (114) is also

synthesized^69 from the nitration of 3-acetyl-1,2,4-triazole with anhydrous nitric acid in acetic

anhydride at subambient temperature followed by hydrolysis of the acetyl functionality. The

ammonium salt of 3,5-dinitro-1,2,4-triazole (113) is itself a useful explosive which forms a

eutectic with ammonium nitrate.^70

NO 2

NO 2

ClCl

N

N

H

N

H 2 N

H 2 N

NO 2

N

NN

N

N

N N

N

NH 2

O 2 N NO

2

+ 2

116

(DANTNP)

EtONa, EtOH

60 %

115 114

NN

Figure 7.43