1,2,3,4-Cyclobutanetetranitramine Derivatives
J . Org. Chem., Vol. 61, No. 26, 1996 9343
Octah ydr o-1,3,4,6-tetr an itr o-3ar,3bâ,6aâ,6br-cyclobu ta-
[1,2-d :3,4-d ′]d iim id a zole-2,5-d ion e (1). Bisurea 9 (250 mg,
1.5 mmol) was added in portions to a stirred solution of 25%
dinitrogen pentoxide in nitric acid at 0 °C. The resulting white
suspension was slowly allowed to warm to ambient tempera-
ture and then stirred overnight. Vacuum filtration of the
white suspension, with thorough washing with water and
drying, gave the desired nitramine 1 in 97% yield (0.50 g). This
reaction works equally as well with lower concentration
dinitrogen pentoxide solutions or even neat 100% nitric acid.
High yields are still achieved when scaled up to 2-3 g of
bisurea 9: 1H NMR (DMSO-d6) δ 5.51 (s); 13C NMR (DMSO-
d6) δ 55.0, 141.2; IR (KBr) 3030, 3000, 1810, 1580, 1310, 1250,
1100 cm-1. Anal. Calcd for C6H4N8O10: C, 20.70; H, 1.16; N,
32.19. Found: C, 20.40; H, 1.20; N, 32.39.
1,3,4,6-tetramethyl-3aR,3bâ,6aâ,6bR-cyclobuta[1,2-d:3,4-d′]di-
imidazole (10; 275 mg, 72%), suitable for use in subsequent
reactions; sublimes 55 °C (0.1 Torr): 1H NMR (DMSO-d6) δ
2.29 (s, 12), δ 3.27 (s, 4), 3.38 (AB quartet, 4, J ) 6.3 Hz); 13
C
NMR (acetone-d6) δ 38.4, 64.6, 78.6; IR (KBr) 2920, 1460, 1440,
1360, 1215, 1145, 1095, 995 cm-1
.
Dinitrogen tetroxide (5 mL) was added in one portion to
tetramethyltetramine 10 (100 mg, 0.5 mmol) in carbon tetra-
chloride (5 mL) at room temperature. The deep red solution
was stirred overnight and then carefully poured into water
(25 mL). This two-phase mixture was extracted with dichlo-
romethane (3 × 20 mL). The organic extracts were combined,
washed with saturated sodium bicarbonate (20 mL) and brine
(20 mL), and dried (MgSO4); solvent was removed under
reduced pressure, giving tetranitrosamine 11 (100 mg, 68%)
as a yellow solid; mp 247-249 °C dec. The molecular structure
of 11 was confirmed by an X-ray structure determination:12
1H NMR (DMSO-d6) δ 3.00 (s, 12), 6.19 (s, 4); 13C NMR (DMSO-
d6) δ 33.2 (q), 61.4 (d); IR (KBr) 3020, 1435, 1345, 1210, 1125,
N,N′,N′′,N′′′-Tet r a n it r o-1r,2r,3â,4â-cyclob u t a n et et r a -
m in e (3). Nitrourea 1 (2.8 g, 8 mmol) was suspended in water
(50 mL) containing sulfuric acid (1 mL) and refluxed with
vigorous stirring until the solid completely dissolveds
approximately 4-6 h. The resulting light-brown solution was
cooled and concentrated until a brown precipitate formed. The
primary tetranitramine 3 was collected by vacuum filtration
as a beige amorphous solid (0.87 g, 36%); detonates at 156 °C:
1H NMR (DMSO-d6) δ 4.80 (s, 4), 10.76 (s, 4); 13C NMR (DMSO-
1045 cm-1
.
N,N′,N′′,N′′′-Tetr a m eth yl-N,N′′′-d in itr o-N′,N′′-d in itr oso-
1r,2r,3â,4â-cyclobu ta n etetr a m in e (12). Dinitrogen pen-
toxide in chloroform (0.8 M, 5 mL) was added directly to
tetramethyltetramine 10 (56 mg, 0.3 mmol) at 0 °C followed
by stirring for 2.5 h. The reaction was quenched with
saturated sodium bicarbonate (25 mL) and extracted with
chloroform (25 mL). Washing the organic layer with brine (25
mL), drying (MgSO4), and removal of solvent afforded a white
solid (34 mg). Purification on silica gel, eluting with 75% ethyl
acetate in hexane, followed by recrystallization from ethyl
acetate gave the dinitrodinitrosotetramine 12 as a white
crystalline solid (yield ∼2 mg, 2%); mp 207-209 °C dec. The
molecular structure of 12 was confirmed by an X-ray structure
determination:12 1H NMR (acetone-d6) δ 3.10 (m, 6), 3.44 (m,
6), 5.7 (m, 4); IR (KBr): 3010, 2940, 1520, 1435, 1355, 1300,
1250 cm-1; MS (CI, methane) 321 (MH+).
d6) δ 52.9; IR (KBr): 3280, 3000, 1585, 1400, 1350 cm-1
.
Octah ydr o-1,3,4,6-tetr an itr o-3ar,3bâ,6aâ,6br-cyclobu ta-
[1,2-d :3,4-d ′]d iim id a zole (2). Nitramine 3 (500 mg, 1.7
mmol) was added to a stirring solution of paraformaldehyde
(120 mg, 4.0 mmol) in 80% sulfuric acid (5 mL) at -5 °C. The
brown suspension was stirred for 45 min and then poured into
ice/water (20 mL); the light-brown solid, nitramine 2 (174 mg,
32%), was collected and dried by vacuum filtration; mp 228
°C dec. A crystal suitable for X-ray structure determination12
was grown from 100% nitric acid: 1H NMR (DMSO-d6) δ 5.44
(s, 4), 5.82 (slightly br s, 4); 13C NMR (DMSO-d6) δ 62.4 (d),
67.8 (t); IR (KBr) 2970, 1520, 1390, 1295, 755, 575 cm-1; MS
(CI, methane) 321 (MH+).
N ,N ′,N ′′,N ′′′-T e t r a m e t h y l-N ,N ′,N ′′,N ′′′-t e t r a n it r o -
1r,2r,3â,4â-cyclob u t a n et et r a m in e (13). Dinitrodinitro-
sotetramine 12 (78 mg, 0.24 mmol) was added to a solution of
trifluoroperoxyacetic acid in dichloromethane (made in situ by
addition of 1.5 mL of 90% hydrogen peroxide to 9.6 mL of
trifluoroacetic anhydride in 15 mL of dichloromethane) at 0
°C. After 5 min, the solution was refluxed for 4 h. The
reaction was then cooled, quenched with saturated sodium
bicarbonate, and extracted with chloroform (2 × 25 mL).
Combining the organic layers, washing with water (25 mL)
and brine (25 mL), drying (MgSO4), and removal of solvent
afforded the desired tetranitramine 13 (40 mg, 47%) as a white
solid; mp 262 °C (detonates): 1H NMR (acetone-d6) δ 3.47 (s,
12), 5.78 (s, 4); 13C NMR (DMSO-d6) δ 59.5, 88.4; IR (KBr)
N ,N ′,N ′′,N ′′′-Te t r a m e t h yl-N ,N ′,N ′′,N ′′′-t e t r a n it r oso-
1r,2r,3â,4â-cyclobu ta n etetr a m in e (11). Bisurea 9 (0.75 g,
4.5 mmol) was added in one portion to sodium hydride (0.52
g, 21 mmol) suspended in THF at ambient temperature. This
mixture was stirred for 45 min followed by addition of dimethyl
sulfate (2.03 mL, 21 mmol), and the resultant mixture was
heated at reflux overnight. After cooling to room temperature,
the cloudy white solution was filtered and solvent was removed
under reduced pressure to yield the crude tetramethylbisurea
(0.92 g) as a white solid; mp 242-250 °C dec. Purification
was accomplished by recrystallization from hot acetone to give
the desired intermediate, octahydro-1,3,4,6-tetramethyl-3aR,-
3bâ,6aâ,6bR-cyclobuta[1,2-d:3,4-d′]diimidazole-2,5-dione, as a
white solid (0.43 g, 50%): 1H NMR (DMSO-d6) δ 2.71 (s, 12),
3.91 (s, 4); 13C NMR (DMSO-d6) δ 28.1, 58.2, 159.7; IR (KBr):
2920, 1510, 1420, 1360, 1285 cm-1
.
2900, 1650, 1440, 1390, 1200, 920 cm-1
.
Su p p or tin g In for m a tion Ava ila ble: ORTEP presenta-
Lithium aluminum hydride (1.4 g, 37 mmol) was added to
the above tetramethylbisurea (436 mg, 1.9 mmol) suspended
in THF at ambient temperature followed by stirring for 3 days
under nitrogen. The resulting suspension was carefully
quenched by adding water (10 drops), 1 M NaOH (10 drops),
and water (10 drops), drying (MgSO4), and removing solvent
under reduced pressure to give an oily solid. Sublimation of
the crude product gave the desired intermediate, octahydro-
1
tions for 2, 11, 12, and 14, presentations of H NMR spectra
for 3 and 13, and a 13C NMR spectrum for 13 (7 pages). This
material is found in libraries on microfiche, immediately
follows this article in the microfilm version of the journal, and
can be ordered from the ACS; see any current masthead page
for ordering information.
J O9613040