IGNATOVICH et al.
944
diamines 3 and 4 were obtained in 78–80% yield.
An important factor responsible for the catalytic activ-
ity of the Ni/Co composite is the ratio of initial nickel
and cobalt nitrates. The most active was the nanocata-
lyst obtained from Ni(NO3)2·6H2O–Co(NO3)2·6H2O
at a ratio of 5:1. The nanocatalyst can be readily
separated from the products by filtration and reused.
with petroleum ether. In the isolation of compound 3,
the filtrate was acidified with 0.4 mL of concentrated
aqueous HCl to pH 1, and the precipitate of 4-methyl-
benzene-1,3-diamine dihydrochloride was filtered off,
washed with dilute (1 :1) aqueous HCl, dried, and
recrystallized from methanol–hexane.
4-Methylbenzene-1,3-diamine dihydrochloride
(3). Yield 82%, white crystals, mp >200°C (decomp.).
IR spectrum (KBr), ν, cm–1: 3300, 2980 (NH), 1612,
1580, 1475, 1200, 1190. Mass spectrum, m/z (Irel, %):
122.05 (100), 108.02 (52) [M – CH3]+, 78.01 (26),
51 (15). Found, %: C 43.00; H 6.22; Cl 36.37;
N 14.35. C7H12Cl2N2. Calculated, %: C 43.10; H 6.20;
Cl 36.35; N 14.36.
6-Methyl-N1-[4-(pyridin-3-yl)pyrimidin-2-yl]-
benzene-1,3-diamine (4). Yield 77%, yellow crystals,
mp 138–140°C; published data [4]: mp 134–136°C. IR
spectrum (KBr), ν, cm–1: 3340, 3235, 3044, 1580,
1551, 1450. Mass spectrum, m/z (Irel, %): 277 (100)
[M]+, 262 (90) [M – CH3]+, 121 (20), 77 (4.5).
Thus, the efficiency of the Ni/Co nanocatalyst in
the reduction of nitroarenes with hydrazine hydrate is
comparable with the efficiency of Raney nickel, and
the proposed procedure conforms to the “green chem-
istry” principles.
Nickel–cobalt nanocatalyst. Aliquots of distilled
water, 200 mmol of Ni(NO3)2·6H2O, and 200 mmol of
Co(NO3)2·6H2O were mixed together, three aliquots
of NaBH4 (458 μL each, 300 mmol) in DMSO were
added in 1-min intervals with stirring on a magnetic
stirrer, and the resulting sol was subjected to ultrasonic
treatment for 2 h while gradually raising the tempera-
ture to 52–58°C. The concentrations of the components
in the reaction mixture were as follows: DMSO,
15 vol %; Ni(NO3)2 ·6 H2O, 15 mmol; Co(NO3)2·
6H2O, 3 mmol; NaBH4, 55 mmol; water–DMSO ratio
1:1. The Ni/Co sol was separated by centrifugation for
10 min at 10000 rpm, washed with distilled water and
then with ethanol, and stored wet at ~6°C.
The IR spectra were recorded in KBr on a Bruker
Tenzor 27 spectrometer. The mass spectra were ob-
tained on a Thermo Scientific Trace GC Ultra DSQ II
instrument. The elemental compositions were deter-
mined on a Vario MICRO Cube automated CHNS
analyzer. The melting points were measured on
a Kofler hot stage. Ultrasonic treatment was performed
with an ElmaSonic S30H ultrasonic bath (Germany).
Reduction of nitroarenes 1 and 2 (general proce-
dure). A suspension of 0.5 mmol of nitro compound 1
or 2 in 1 mL of ethanol was heated to 50°C, 0.05 mmol
of Ni/Co nanocatalyst in 1 mL of ethanol was added
with stirring, the mixture was stirred for 5–7 min, and
0.18 mL (3.5 mmol, 5 equiv) of hydrazine hydrate was
added dropwise. The mixture was refluxed for 20–
45 min, the progress of the reaction being monitored
by TLC. When the reaction was complete, the warm
mixture was filtered through a layer of celite, the
sorbent was washed with ethanol, and the filtrate was
combined with the washings and evaporated. The
residue was dissolved in 10 mL of ethyl acetate, the
solution was washed with water and evaporated to 1/3
of the initial volume, and the product was precipitated
REFERENCES
1. Mitsudome, T. and Kaneda, K., ChemCatChem, 2013,
vol. 5, p. 1681.
2. Ignatovich, Zh.V., Kadutskii, A.P., Koroleva, E.V.,
Baranovskii, A.V., and Gusak, K.N., Russ. J. Org. Chem.,
2009, vol. 45, p. 1070.
3. Rai, R.K., Mahata, A., Mukhopadhyay, S., Gupta, S.,
Li, P.-Z., Nguyen, K.T., Zhao, Ya., Pathak, B., and
Singh, S.K., Inorg. Chem., 2014, vol. 53, p. 2904.
4. Szakacs, Z., Beni, S., Vagra, Z., Orfi, L., Keri, G., and
Noszal, B., J. Med. Chem., 2005, vol. 48, p. 249.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 54 No. 6 2018
Ignatovich, Zh. V.
