Organic Chemistry of Explosives

76 Polynitropolycycloalkanes

Tests onD 3 -hexanitrotrishomocubane show it to be both less sensitive and significantly more

powerful than TNT whilst exhibiting high thermal stability.

Polynitro derivatives of pentacyclo[5.4.0.0^2 ,^6 .0^3 ,^10 .0^5 ,^9 ]undecane^17 −^19 have attracted inter-

est as potential high-energy explosives. Molecular strain in this caged system could arise from

both the constrained norbornyl moiety and the cyclobutane ring. Additional strain would be

expected from nonbonding interactions if the 8-endoand 11-endopositions were substituted

withgem-dinitro groups.

(^62) O
O
(^63) NOH
NOH
Br
Br
NO 2
NO 2
64 65
N
O 2 N OH
NH 2 OH.HCl,
NaOAc, EtOH
87 %
NaBH 4 ,
EtOH (aq)
28 %
NBS, NaHCO 3 ,
dioxane
49 %
Figure 2.15
O
O
O
NOH
O
O
O
O
Br NO 2
O
O
H NO 2
O 2 N NO 2
NO 2
NO 2
O
O
O
O
O 2 N NO 2
O 2 N NO 2
NOH
66
69 68
67
72
NH 2 OH.HCl,
NaOAc, EtOH
NaBH 4 , EtOH (aq)
K 3 Fe(CN) 6 , NaOH
NaNO 2 , MeOH (aq)

1. 98 % red HNO 3 ,
   NH 4 NO 3 , CH 2 Cl 2 ,
   reflux

62

TsOH, PhH,

HOCH 2 CH 2 OH

Dean–Stark

92 %

79 %

1. Br 2 , DMF,
   NaHCO 3


2. O 3 , CH 2 Cl 2
   80 % (2 steps)

70

73 % 97 %

71

1. conc. H 2 SO 4 ,
   CH 2 Cl 2 , 73 %


2. NH 2 OH.HCl,
   NaOAc, EtOH,
   89 %


3. 30 % H 2 O 2 (aq),
   reflux
   31 % (2 steps)

Figure 2.16

Marchand and co-workers have provided synthetic routes to both 8,8,11,11-tetranitro- (72)^17

and 4,4,8,8,11,11-hexanitro- (80)^18 pentacyclo[5.4.0.0^2 ,^6 .0^3 ,^10 .0^5 ,^9 ]undecanes. Initial attempts

to synthesize target (72) from the dioxime (63) failed when it was found that sodium boro-

hydride reduction of thegem-bromonitro intermediate (64) gave the aza-heterocycle (65) as

the major product. Consequently, an indirect route was explored where one of the two ketone

groups of (62) is protected as an acetal (66) while the other ketone group is converted to a