1460
M. C. Davis
room temperature (228C). The 1,3,5-benzenetricarbonyl triazide (5) should not
be stored but immediately dissolved in alcohol and reacted.] A 1-L, two-neck,
round-bottomed flask equipped with magnetic stirbar was charged with
200 mL of H2O, and 20 mL of conc. HCl (0.238 mol, 6 equiv) was added
over 5 min. In one portion, 10 g of 4 (0.039 mol) was added, and the mixture
was allowed to stir for 15 min, becoming a pale yellow solution. The
mixture was placed in an ice bath, and a thermometer was equipped to
monitor internal temperature. An addition funnel containing a solution of
17 g of NaNO2 (0.199 mol, 5 equiv) in 50 mL of H2O was equipped to the
second neck. The nitrite solution was added over 1 h, making sure to keep
the temperature at ꢀ 108C. The 1,3,5-benzenetricarbonyl triazide (5) [dH
(CDCl3): 8.86 (s, 3H); dC (CDCl3): 170.77, 135.14, 132.51] intermediate
precipitated during the addition as copious white solids. The mixture was
stirred 20 min further in the ice bath. Ether (200 mL) was added, and the
cooling bath was removed. The organic phase was separated, and the
aqueous phase was extracted twice more with 200-mL portions of Et2O.
The organic extracts were collected and washed with 200 mL of H2O,
100 mL of saturated aqueous Na2CO3, and finally 200 mL of brine. The
organic phase was dried over anhydrous MgSO4, transferred to a 2-L, round-
bottomed flask and rotary evaporated (10 mm Hg, 228C). Absolute EtOH
(1 L) followed by a magnetic stirbar were immediately added to the flask
containing 5, and the mixture was refluxed for 18 h. The pale yellow solution
was rotary evaporated, leaving an off-white foamy residue (11.45 g, 85%).
The residue was recrystallized from MeCN/H2O to give the title compound as
a white crystalline powder. Mp 101–1058C (lit.[4] 110–1118C). dH (DMSO):
9.49 (s, 3H), 7.28 (s, 3H), 4.09 (q, J ¼ 7.2 Hz, 6H), 1.23 (t, J ¼ 7.2 Hz, 9H);
dC (DMSO): 153.45, 139.59, 103.79, 59.96, 14.54.
Triethyl N,N0,N00-1,3,5-Triamino-2-nitrobenzenetricarbamate (7)
A 25-mL, round-bottomed flask equipped with magnetic stirbar was charged
with 10 mL of conc. H2SO4. The flask was cooled in an ice bath before adding
1 g of 6 (2.9 mmol) in a single portion. The cooling bath was removed, and the
mixture was stirred at rt. After all the solids dissolved, the flask was cooled in
the ice bath, and 130 mL of 100% HNO3 (3.2 mmol, 1.1 equiv) was added
dropwise in 10 min. Immediately the mixture becomes a dark brown color.
The cooling bath was removed, and the mixture slowly becomes light
brown in color. After 30 min, the mixture was poured onto 100 mL of
crushed ice and H2O, and a light yellow solid precipitated. The product was
collected on a coarse-porosity glass frit and washed with H2O several times.
Recrystallized from HOAc/H2O to give bright yellow needles. Mp 134–
1368C. dH (DMSO, 300 MHz): 10.15 (s, 1H), 9.44 (s, 2H), 7.48 (s, 2H),
4.13 (q, J ¼ 7.9 Hz, 2H), 4.05 (q, J ¼ 7.9 Hz, 4H), 1.24 (t, J ¼ 7.9 Hz, 3H),