Organic Chemistry of Explosives

300 N-Heterocycles

Coburn^17 synthesized 3-nitro-4-(picrylamino)furazan (37) from the reaction of DAF (24)

with one equivalent of picryl fluoride (35) followed by oxidation of the remaining amino group

with hydrogen peroxide in trifluoroacetic acid.

Cl

NOH

Cl

HON

38

NH 2

+ 2

NHPh

NOH

PhHN

HON

39

NaOH,

HOCH 2 CH 2 OH

N

O

N

PhHN NHPh

40

N

O

N

41

(BPAF)

H

N

H

N

O 2 N

O 2 N

NO 2

NO 2

NO 2

O 2 N

conc. HNO 3 , 25 °C

86 %

Figure 7.16

Coburn^17 also reported the synthesis of BPAF (41), the 3,4-bis-picrylamino derivative of

furazan. Thus, reaction of two equivalents of aniline with 1,2-dichloroglyoxime (38) yields

the bis-aniline (39), which on treatment with sodium hydroxide in ethylene glycol undergoes

cyclization to the furazan (40), and nitration of the latter with concentrated nitric acid at room

temperature yields BPAF (41).

N

O

N

2 N NH

N

O

N

N NH 2

O

N

N

NN

O

N NO

N

NO 2 N 3

27

(DAAF)

N

O

N

3 NN

N

O

N

N N 3

O

42

43

N

N

NN

O

N NO

N

44

(NOTO)

MeCN,

heat

1. H 2 SO 4 , AcOH,
   NaNO 2
   2. 30 % H 2 O 2 , H 2 SO 4 ,
   (NH 4 ) 2 S 2 O 8 , 35 °C
   
   
   1. SnCl 2 , MeOH
   
   
   
   


2. NaN 3

Figure 7.17

Boyer and Gunasekaren^26 reported the synthesis of the furazan-based heterocycle

NOTO (44), which contains 50 % by mass of nitrogen and is a liquid at room tempera-

ture. The five-step synthesis of NOTO (44) starts from the diazotization of 4,4′-diamino-3,3′-

azoxyfurazan (DAAF) (27), followed by reaction with sodium azide to form the diazide (42).

Heating the diazide (42) as a solution in acetonitrile induces cyclization to the triazole (43)

and this is followed by reduction and oxidation of the remaining azide group to complete the

synthesis of NOTO (44).