The Methyl and Ethyl Carbamates of Aniline
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Diethyl N,N0-4-Nitro-1,2-diaminobenzene Dicarbamate (10)
A 100-mL Erlenmeyer flask equipped with a magnetic stirbar was charged
with 10 mL of conc. HNO3. The mixture was stirred in an ice bath, and 1 g
of 4 (3.9 mmol) was added in one portion. The cooling bath was removed,
and the mixture was stirred at rt for 4 h. After this time, a tan solid had pre-
cipitated. The mixture was poured onto 100 g of crushed ice and H2O, and
a tan solid precipitated (850 mg, 74%). The solid was recrystallized from
EtOH to give the title compound as soft white needles. Mp 173–1758C. dH
(CDCl3): 8.32 (d, J ¼ 2.7 Hz, 1H), 8.10 (dd, J ¼ 9.2 and 2.4 Hz, 1H), 7.99
(d, J ¼ 9.0 Hz, 1H), 7.39 (bs, 1H), 6.78 (bs, 1H), 4.3 (q, J ¼ 7.0 Hz, 2H),
4.29 (q, J ¼ 7.2 Hz, 2H), 1.36 (t, J ¼ 7.2 Hz, 3H); dH (DMSO): 9.29
(s, 1H), 9.18 (s, 1H), 8.44 (d, J ¼ 2.2 Hz, 1H), 7.99–7.84 (m, 2H), 4.15
(q, J ¼ 7.1 Hz, 2H), 4.14 (q, J ¼ 7.1 Hz, 2H), 1.24 (t, J ¼ 7.0 Hz, 6H); dC
(DMSO): 154.09, 153.61, 142.52, 136.36, 129.21, 121.92, 119.49, 118.40,
61.19, 61.03, 14.39, 14.36.
Diethyl 4,5-Dinitro-1,2-diaminobenzenedicarbamate (11) and
Diethyl 4,6-Dinitro-1,2-diaminobenzenedicarbamate (12)
A 50-mL Erlenmeyer flask equipped with magentic stirbar was charged with
10 mL of conc. H2SO4 and cooled in an ice bath. In one portion, 1 g of 4
(3.9 mmol) was to the flask, and the cooling bath was removed. After most
of the solids had dissolved, the cooling bath was replaced. Nitric acid
(100%, 0.4 mL, 9.8 mmol, 2.5 equiv) was added dropwise over 2 min. The
cooling bath was removed, and the mixture was stirred at rt for 1 h. The
mixture was poured onto 100 g of cracked ice, and the tan solid was
1
collected on a coarse frit and air-dried (1.3 g, 96%). H NMR showed the
product was a 1:1 mixture of the title compounds: diethyl 4,5-dinitro-1,2-dia-
minobenzenedicarbamate (11) dH (DMSO): 9.73 (s, 2H), 8.52 (s, 2H), 4.21
(q, J ¼ 7.4 Hz, 4H), 1.29 (t, J ¼ 7.0 Hz, 6H); and diethyl 4,6-dinitro-1,2-dia-
minobenzenedicarbamate (12) dH (DMSO): 9.78 (bs, 1H), 9.6 (bs, 1H), 8.85
(d, J ¼ 2.6 Hz, 1H), 8.39 (d, J ¼ 2.6 Hz, 1H), 4.11 (q, J ¼ 7.4 Hz, 4H), 1.23
(t, J ¼ 7.4 Hz, 6H).
Diethyl N,N0-2-Nitro-1,4-diaminobenzene Dicarbamate (13)
A 100-mL Erlenmeyer flask equipped with magnetic stirbar was charged with
20 mL of glacial HOAc, 1 g of 5 (3.9 mmol), and 387 mL of conc. HNO3
(270 mg, 4.3 mmol, 1.1 equiv). The mixture was stirred at rt for 3 h. A bright
yellow solid had precipitated during the reaction. The mixture was poured
onto 100 g of crushed ice and H2O. The bright yellow solid was collected on a
coarse-porosity glass frit, washed with H2O, and air dried (1.15 g, 97%). The