Organic Chemistry of Explosives

Hydrolysis of nitramides and nitroureas 231

Methylenedinitramine (1,3-dinitro-1,3-diazapropane) (168) can be prepared from the ni-

tration of the bis-acetamide (166), followed by hydrolysis of the product (167) with barium

hydroxide and subsequent acidification.^135 Methylenedinitramine has no practical value as an

explosive due to its facile decomposition in solution.

Bachman and co-workers^70 studied the synthesis of the high explosive ethylenedinitramine

(2) (EDNA) from the hydrolysis of secondary nitramides. One of the oldest routes to EDNA

(2) involves the nitration of 2-imidazolidone (66) with mixed acid, followed by hydrolysis of

the resultingN, N′-dinitro-2-imidazolidone (67) with boiling water.^136 2-Imidazolidone (66)

is readily synthesized from the reaction of urea with ethylene glycol,^137 or by treating either

urea^137 or ethyl carbonate^70 with ethylenediamine.

NHHN

O

NN

O

HNO 3 O 2 NNO 2

H 2 SO 4

O 2 NHN

NHNO 2

NHCO 2 Et

NHCO 2 Et

NCO 2 Et

NCO 2 Et

NO 2

NO 2

N

N

H

H

O

O

N

NO

O

NO 2

NO 2

HNO 3 , Ac 2 O

NHCOCH 3

NHCOCH 3

NCOCH 3

NCOCH 3

NO 2

NO 2

66 67

98 % HNO 3

0-5 °C, 95 %

1. NH 4 OH
   reflux


2. HCl (aq)
   95 %

2

55

56

H (EDNA)

2 O

reflux

90 %

57

169

58

170

83 %

1. NH 4 OH
   reflux


2. HCl (aq)


3. NaOH


4. HCl (aq)
   94 %

HNO 3 , Ac 2 O

Figure 5.71 Synthetic routes to ethylenedinitramine (EDNA) via nitramide hydrolysis

The nitration of the carbamate (55) with pure nitric acid, followed by hydrolysis of the

product (56) and subsequent acidification, also yields EDNA (2).^70 ,^136 Acetylation of ethylene-

diamine, followed by nitration of the resulting product,N, N′-ethylenebisacetamide (57), yields

N, N′-dinitro-N, N′-ethylenebisacetamide (58), an explosive which also yields EDNA (2)^70 on

treatment with aqueous base followed by acidification. EDNA (2) has also been synthesized

from ethyleneoxamide (169); the latter is prepared from the condensation of ethylenediamine

with diethyloxalate.^70

The nitration and hydrolysis of ethyl carbamates like (55) has been used to synthesize

other nitramines, including: 1,3-dinitraminopropane, 1,4-dinitraminobutane, 1,5-dinitramino-

pentane and 1,6-dinitraminohexane.^138 ,^139

The facile hydrolysis ofN, N′-dinitro-2-imidazolidone to ethylenedinitramine (EDNA)

shows thatN, N′-dinitroureas can be useful precursors to linear dinitramines. CyclicN, N′-

dinitroureas can be prepared indirectly from nitroguanidine. Nitroguanidine is found to