Organic Chemistry of Explosives

70 Polynitropolycycloalkanes

Archibald and co-workers^5 found that aminocyclobutanes could be oxidized to the cor-

responding nitrocyclobutanes in moderate yield when usingm-chloroperoxybenzoic acid

(m-CPBA) as oxidant. Using this strategy, 1,3-dinitrocyclobutane (16) was prepared from 1,3-

diaminocyclobutane (15) in 38 % yield. Interestingly, 1,3-dinitrocyclobutane (16) is obtained

as a mixture of isomers from the crude reaction mixture but this completely epimerizes to the

cis-isomer on purification by flash chromatography on silica gel.

NH 2

NH 2

H

H

NO 2

NO 2

H

H

NO 2 NO 2

NO 2 NO 2

O 2 NO 2 N

O 2 N H

m-CPBA,

ClCH 2 CH 2 Cl,

reflux, 38 %

1. NaOH, Na 2 CO 3


2. NaNO 2 , AgNO 3

15 16 17 18

+

17:18 ~ 3:2

(38 % of 17 after recrystallization

from CHCl 3 -CH 2 Cl 2 )

Figure 2.6

The conversion of 1,3-dinitrocyclobutane (16) to 1,1,3,3-tetranitrocyclobutane (17) is compli-

cated by the instability of the disodium salt of 1,3-dinitrocyclobutane in strongly basic solution

or at temperatures above 5◦C. This prevents oxidative nitration with sodium nitrite and potas-

sium ferricyanide in the presence of aqueous sodium hydroxide. However, oxidative nitration of

the disodium salt of 1,3-dinitrocyclobutane with a mixture of silver nitrate and sodium nitrite

generated a 3:2 mixture of 1,1,3,3-tetranitrocyclobutane (17) and 1,1,3-trinitrocyclobutane

(18), from which the former was isolated in 38 % yield after fractional recrystallization from

chloroform–methylene chloride. Attempts to convert 1,1,3-trinitrocyclobutane (18) to 1,1,3,3-

tetranitrocyclobutane (17) fail under the conditions of oxidative nitration. This is possibly

due to the instability of the anion of 1,1,3-trinitrocyclobutane in aqueous solution, which

may also account for the relatively low yield for the conversion of (16) to (17). 1,1,3,3-

Tetranitrocyclobutane (17) is found to have a crystal density of 1.83 g/cm^3 , and although the

compound rapidly degrades in alkaline solution, it is thermally stable up to its melting point

of 165◦C.

NOH

NOH

HNO 2

HNO 2

O 2 N

O 2 N

NO 2

NO 2

1. Na, NH 3 , MeOH


2. m-CPBA,
   ClCH 2 CH 2 Cl
   13 % (2 steps)
   
   
   1. NaOH, dioxane
   
   
   2. NaNO 2 , K 3 Fe(CN) 6 ,
      Na 2 S 2 O 8 , 64 %
      19 20 21
   
   
   
   

Figure 2.7

Archibald and co-workers^5 used a similar strategy of amine oxidation, followed by

oxidative nitration, for the conversion of 5,10-diaminodispiro[3.1.3.1]decane to 5,5,10,10-

tetranitrodispiro[3.1.3.1]decane (21). 5,10-Diaminodispiro[3.1.3.1]decane was prepared from

the reduction of the corresponding oxime (19) with sodium in liquid ammonia–methanol.

5,10-Dinitrodispiro[3.1.3.1]decane (20) undergoes oxidative nitration to give 5,5,10,10-

tetranitrodispiro[3.1.3.1]decane (21) in 64 % yield.

2,5,8,10-Tetranitrodispiro[3.1.3.1]decane (24) was obtained as a mixture of isomers by treat-

ing the oxime (22) with chlorine in methylene chloride, followed by oxidation with hypochlo-

rite and reductive dehalogenation of the resultinggem-chloronitro intermediate (23) with zinc