NIKOLAENKOVA et al.
1090
Scheme 2.
NMe2
NO2
NO2
N
N
O
4-Me2NC6H4N=O·HCl
NaOH, H2O
Pyridine
I
NO2
NO2
Br–
MeO
MeO
IV
V
HCl
II (90%)
base N-oxide V gave aldehyde II in 90% yield
(Scheme 2).
(22.5 mmol) of sodium hydroxide in 2 ml of water.
The mixture was stirred for 1 h at room temperature,
and the precipitate was filtered off, washed with water,
and dried.
To conclude, we have proposed procedures ensur-
ing preparation of 4-(4-methoxyphenyl)-2,6-dinitro-
benzaldehyde in high yield under mild conditions.
N-(4′-Methoxy-3,5-dinitrobiphenyl-4-ylmethyli-
dene)-4-(dimethylamino)aniline N-oxide (V). Yield
3.8 g (95%), mp 184°C (decomp., from EtOAc).
1H NMR spectrum (DMSO-d6), δ, ppm: 3.01 s [6H,
N(CH3)2], 3.84 s (3H, CH3O), 6.80 d (2H, Harom, J =
9.2 Hz), 7.12 d (2H, Harom, J = 8.8 Hz), 7.69 d (2H,
Harom, J = 9.2 Hz), 7.92 d (2H, Harom, J = 8.8 Hz),
8.62 s (2H, Harom), 8.76 s (1H, CH=N). Found: m/z
436.1375 [M]+. C22H20N4O6. Calculated: M 436.1377.
4-(4-Methoxyphenyl)-2,6-dinitrobenzaldehyde
(II). a. A suspension of 0.25 g (2.98 mmol) of
NaHCO3 and 0.5 g (1.36 mmol) of compound I in 5 ml
of DMSO was stirred for 30 min at room temperature.
The mixture was then heated for 5 min at 70°C,
cooled, poured into 20 ml of water, neutralized with
10% aqueous HCl, and extracted with chloroform
(2×10 ml). The combined extracts were evaporated,
the residue (0.41 g) containing aldehyde II and alcohol
III at a ratio of 2:1 (GC/MS data) was dissolved in
30 ml of methylene chloride, 4.75 g (22 mmol) of pyr-
idinium chlorochromate was added, and the mixture
was stirred for 5 h at room temperature. The product
was isolated by chromatography in a 20×4-cm column
charged with silica gel; eluent hexane–chloroform,
1:1. Yield 0.37 g (90%), mp 127–128°C; published
N-Oxide V was mixed with 35 ml of concentrated
aqueous HCl, and the mixture was heated for 2 h at
40–45°C. The mixture was poured into 30 ml of water
and extracted with chloroform (2×20 ml), the extracts
were combined and concentrated, and the residue was
subjected to column chromatography (see above) to
isolate 2.6 g (90%) of II with mp 127–128°C.
1
4-(4-Methoxyphenyl)-2,6-dinitrobenzyl alcohol
(III). A solution of 0.5 g (1.36 mmol) of compound I
in 10 ml of DMSO was stirred for 30 min at room
temperature, 1.35 g (16 mmol) of NaHCO3 was added,
and the mixture was stirred for 40 min at room tem-
perature. The mixture was then poured into 20 ml of
water, neutralized with 10% aqueous HCl, and extract-
ed with chloroform (2×10 ml); the combined extracts
were partly evaporated, and the residue was subjected
to chromatography in a 20×4-cm column charged with
silica gel using hexane–chloroform (1:1) as eluent.
Yield 0.39 g (94%), mp 123–124°C. IR spectrum
(CHCl3), ν, cm–1: 3597, 3005, 2841, 1545, 1520, 1352.
1H NMR spectrum, δ, ppm: 3.85 s (3H, CH3O), 4.93 s
(2H, CH2), 7.01 d (2H, 3′-H, 5′-H, J = 8.9 Hz), 7.54 d
(2H, 2′-H, 6′-H, J = 8.9 Hz), 8.17 s (2H, 3-H, 5-H).
Found: m/z 304.0690 [M]+. C14H12N2O6. Calculated:
M 304.0688.
data [2]: mp 118–123°C. H NMR spectrum, δ, ppm:
3.88 s (3H, CH3O), 7.06 d (2H, Harom, J = 7.0 Hz),
7.62 d (2H, Harom, J = 7.0 Hz), 8.58 s (2H, Harom),
10.58 s (1H, CHO). Found: m/z 302.0536 [M]+.
C14H10N2O6. Calculated: M 302.0533.
b. Alcohol III, 0.85 g (2.8 mmol), was dissolved in
50 ml of methylene chloride, 9.5 g (44 mmol) of PCC
was added, and the mixture was stirred for 5 h at room
temperature. The mixture was then subjected to
column chromatography as described above to isolate
0.84 g (99%) of aldehyde II with mp 127–128°C.
c. A mixture of 3.5 g (9.5 mmol) of compound I
and 10 ml of pyridine was stirred at room temperature
until a suspension of pyridinium salt IV was obtained.
To the resulting suspension we added under stirring
30 ml of water, 1.9 g (10 mmol) of N,N-dimethyl-4-
nitrosoaniline hydrochloride, and a solution of 0.9 g
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 7 2013
Nikolaenkova
