JOURNAL OF CHEMICAL RESEARCH 2017 511
J = 8.0 Hz, 1H), 6.70 (t, J = 8.0Hz, 1H), 4.04 (s, 2H); MS (ESI): [M(35Cl)
+ H]+, m/z 128.
3-Chloroaniline (Table 3, entry 5):37 Yellow oil; 1H NMR (400 MHz,
CDCl3): δ 7.06 (t, J = 8.0 Hz, 1H), 6.72 (d, J = 8.0 Hz, 1H), 6.67 (s, 1H),
6.55 (d, J = 8.0 Hz, 1H), 3.71 (s, 2H); MS (ESI): [M(35Cl) + H]+, m/z
128.
halogen substituted nitrobenzenes were reduced to the
corresponding chloroanilines in high yields and without any
dehalogenation (Table 3, entries 4–7). The reducible functional
group –COOH remained unchanged under the reaction
conditions (Table 3, entry 11). The reduction reactions of
nitroanilines gave the corresponding diaminobenzenes in
excellent yields (Table 3, entries 12 and 13). To our surprise,
this catalyst system was suitable for the reduction of N-(5-nitro-
2-methylphenyl)-4-(3-pyridyl)pyrimidine-2-amine (Table 3,
entry 14), which is an important intermediate in the manufacture
of an anti-cancer drug named Imatinib. Our catalyst system has
the advantage of higher purity, better yield and lower cost than
other methods.33–36
4-Bromoaniline (Table 3, entry 6):41 Brown solid; m.p. 65–68 ºC (lit.41
60–62 ºC); 1H NMR (400 MHz, CDCl3): δ 7.23 (d, J = 8.0 Hz, 2H), 6.56
(d, J = 8.0 Hz, 2H), 3.64 (s, 2H); MS (ESI): [M(79Br) + H]+, m/z 172.
2,4,6-Trichloroaniline (Table 3, entry 7):42 Colourless solid; m.p.
72–74 ºC (lit.42 68–70 ºC); 1H NMR (400 MHz, CDCl3): δ 7.19 (s, 2H),
4.40 (s, 2H); GC–MS: [M(35Cl)]+, m/z 195.
1
2,6-Dimethylaniline (Table 3, entry 8):37 Yellow oil; H NMR (400
MHz, CDCl3): δ 6.96 (d, J = 8.0 Hz, 2H), 6.67 (t, J = 8.0 Hz, 1H), 4.01
(s, 2H), 2.21 (s, 6H); MS (ESI): [M + H]+, m/z 122.
Conclusion
m-Aminophenol (Table 3, entry 9):39 Tan solid; m.p. 115–118 ºC (lit.39
In summary, an efficient and green protocol for the synthesis
of aromatic amines from the corresponding nitroaromatic
compounds with NH2NH2·H2O catalysed by H2O2-treated AC
in DMF at 100 ºC has been developed.
1
119–120 ºC); H NMR (400 MHz, DMSO-d6): δ 8.89 (s, 1H), 6.81 (t,
J = 8.0 Hz, 1H), 6.04 (d, J = 8.4 Hz, 2H), 5.97 (d, J = 7.6 Hz, 1H), 4.86
(s, 2H); MS (ESI): [M + H]+, m/z 110.
p-Aminophenol (Table 3, entry 10):37,43 Brown solid; m.p. 193–196 ºC
(lit.43 192–194 ºC); 1H NMR (400 MHz, DMSO-d6): δ 8.34 (s, 1H), 6.46
(d, J = 8.0Hz, 2H), 6.40 (d, J = 8.0 Hz, 2H), 4.38 (s, 2H); MS (ESI): [M
+ H]+, m/z 110.
4-Aminobenzoic acid (Table 3, entry 11):37,44 Pale yellow solid; m.p.
185–187 ºC (lit.44 186 ºC); 1H NMR (400 MHz, DMSO-d6): δ 11.96 (s,
1H), 7.61 (d, J = 8.2 Hz, 2H), 6.54 (d, J = 8.2 Hz, 2H), 5.87 (s, 2H); MS
(ESI): [M + H]+, m/z 138.
o-Phenylenediamine (Table 3, entry 12):45,46 Colourless solid; m.p.
101–104 ºC (lit.46 98–100 ºC); 1H NMR (400 MHz, DMSO-d6): δ 6.52
(s, 2H), 6.39 (s, 2H), 4.39 (s, 4H); MS (ESI): [M + H]+, m/z 109.
p-Phenylenediamine (Table 3, entry 13):39 Purple solid; m.p. 142–145
ºC (lit.39 141 ºC); 1H NMR (400 MHz, CDCl3): δ 6.57 (s, 4H), 3.34 (s,
4H); MS (ESI): [M + H]+, m/z 109.
Experimental
All the chemicals were obtained from Tianjin Kermel Chemical
Reagent Co. Ltd and were used as received. The H2O2-treated AC was
characterised using FTIR (Thermo Nicolet Corporation NEXUS).
The reactions were monitored by LC–MS (Waters/WATERS UPLC-
TQD, Table 3, entries 2–6 and 8-15) and GC–MS (GCMS-QP2010
SE, Table 3, entries 1 and 7). The products were characterised using
1H NMR (Bruker Avance/400 and Bruker Avance Ⅲ HD/600) using
CDCl3 or DMSO-d6 as the solvent and TMS as internal standard. Data
are represented as follows: chemical shift, integration, multiplicity (s =
singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broad)
and coupling constants (J) in Hertz (Hz).
N-(5-amino-2-methylphenyl)-4-(3-pyridyl)pyrimidine-2-amine
(Table 3, entry 14):47 Yellow solid; m.p. 145–148 ºC (lit.47 138–140 ºC);
1H NMR (400 MHz, CDCl3): δ 9.26 (s, 1H), 8.71 (d, J = 4.0 Hz, 1H),
8.49 (d, J = 4.0 Hz, 1H), 8.34 (d, J = 8.0 Hz, 1H), 7.60 (s, 1H), 7.42 (q, J
= 4.0 Hz, 1H), 7.14 (d, J = 4.0 Hz, 1H), 6.99 (d, J = 8.0 Hz, 2H), 6.41 (d,
J = 8.0 Hz, 1H), 3.30 (s, 2H), 2.24 (s, 3H); MS (ESI): [M + H]+, m/z 278.
Ethyl 2-amino-4,5-bis(2-methoxyethoxy)benzoate (Table 3, entry
Preparation of activated carbon
AC (20 g) was washed with deionised water three times and stirred
with 30% H2O2 (50 mL) overnight. Then the H2O2-treated AC was
filtered off, washed with deionised water until it gave a negative
hydrogen peroxide test on starch–potassium iodide paper and dried to
powder under reduced pressure. Finally, 19.8 g of H2O2-treated AC was
obtained.
1
15):48 Brown oil; H NMR (600 MHz, CDCl3): δ 7.45 (s, 1H), 6.14 (s,
1H), 5.58 (br, 2H), 4.31–4.26 (m, 2H), 4.14–4.11 (m, 2H), 4.08 (t,
J = 4.5 Hz, 2H), 3.78 (t, J = 4.2 Hz, 2H), 3.72 (t, J = 4.5 Hz, 2H), 3.45 (d,
J = 2.9 Hz, 6H), 1.36 (t, J = 7.1 Hz, 3H); MS (ESI): [M + H]+, m/z 314.
Synthesis of amines; general procedure
CAUTION: Due precautions were taken with the handling and use
of hydrazine hydrate (NH2NH2·H2O) due to its toxicity.
Acknowledgements
A mixture of the organic nitro compound (1.0 mmol), NH2NH2·H2O
(2.5 equiv.) and H2O2-treated AC powder (50 wt%) in DMF (1.5 mL)
was stirred vigorously magnetically at 100 ºC. The reaction was
monitored by LC–MS or GC–MS. On completion the reaction mixture
was filtered to remove the catalyst. The combined organic mixture
material was dried using anhydrous Na2SO4 and filtered. The solvent
was removed under reduced pressure to obtain the products. All the
compounds were known and characterised by their H NMR and MS
spectra and comparison with literature data.
Aminobenzene (Table 3, entry 1):37 Yellow oil; 1H NMR (400 MHz,
CDCl3): δ 7.17 (t, J = 8.0 Hz, 2H), 6.77 (t, J = 8.0 Hz, 1H), 6.70 (d,
J = 8.0 Hz, 2H), 3.58 (s, 2H); GC–MS: [M]+, m/z 93.
This work was supported financially by the Key Scientific and
Technological Project of Henan Province (Nos 152102210285
and 152102310312), Innovative Talents Programme of Henan
Province (Nos 164100510015 and 174100510025), Production-
Learning-Research Cooperation Project of Henan Province (Nos
122107000014, 142107000081 and 122107000014), Foundation
of Henan Educational Committee (Nos 18A150030, 14A350005
and 16A350015), the Scientific Research Foundation for Doctors
(No. qd16106) and the Youth Foundation of Henan Normal
University (No. 2016QK09).
1
Electronic Supplementary Information
o-Toluidine (Table 3, entry 2):38 Light-brown liquid; 1H NMR
(400 MHz, CDCl3): δ 7.06 (t, J = 8.0 Hz, 2H), 6.75 (t, J = 8.0 Hz, 2H),
4.18 (s, 2H), 2.20 (s, 3H); MS (ESI): [M + H]+, m/z 108.
The ESI (1H NMR spectra of the products) is available through
ht t p : / / i ngent acon ne ct.com / cont ent / st l /jc r / 2017/
00000041/00000009
p-Aminotoluene (Table 3, entry 3):39 Yellow–orange solid; m.p.
1
44-45 ºC (lit.39 40–44 ºC); H NMR (400 MHz, CDCl3): δ 7.01 (d,
Received 11 February 2017; accepted 5 July 2017
Paper 1704595
Published online: 22 August 2017
J = 8.0 Hz, 2H), 6.64 (d, J = 8.0 Hz, 2H), 3.54 (s, 2H), 2.28 (s, 3H); MS
(ESI): [M + H]+, m/z 108.
1
o-Chloroaniline (Table 3, entry 4):40 Red oil; H NMR (400 MHz,
CDCl3): δ 7.26 (d, J = 8.0 Hz, 1H), 7.07 (t, J = 8.0 Hz, 1H), 6.77 (d,