Reaction of N-arylcarbamoyl-1,4-benzoquinone imines with sodium azide

Article abstract of DOI:10.1134/S1070428014030075

N-Arylcarbamoyl-1,4-benzoquinone imines reacted with sodium azide in completely regioselective fashion according to the 1,4-addition pattern with formation of 1-(3-azido-4-hydroxyphenyl)-3-arylureas. The reaction of N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-benzoquinone imines with sodium azide afforded N-arylcarbamoyl-2,6-diazido-3,5-dimethyl-1,4-benzoquinone imines as a result of nucleophilic substitution of the chlorine atoms.

Full text of DOI:10.1134/S1070428014030075

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 3, pp. 346–350. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © S.A. Konovalova, A.P. Avdeenko, A.G. Sergeeva, I.L. Marchenko, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50,
No. 3, pp. 357–361.
Reaction of N-Arylcarbamoyl-1,4-benzoquinone Imines
with Sodium Azide
S. A. Konovalova, A. P. Avdeenko, A. G. Sergeeva, and I. L. Marchenko
Donbass State Engineering Academy, ul. Shkadinova 72, Kramatorsk, 84313 Ukraine
e-mail: chimist@dgma.donetsk.ua
Received October 25, 2013
Abstract—N-Arylcarbamoyl-1,4-benzoquinone imines reacted with sodium azide in completely regioselective
fashion according to the 1,4-addition pattern with formation of 1-(3-azido-4-hydroxyphenyl)-3-arylureas. The
reaction of N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-benzoquinone imines with sodium azide afforded
N-arylcarbamoyl-2,6-diazido-3,5-dimethyl-1,4-benzoquinone imines as a result of nucleophilic substitution of
the chlorine atoms.
DOI: 10.1134/S1070428014030075
N-Substituted 1,4-benzoquinone imines are known
to fairly readily react with sodium arenesulfinates,
hydrogen halides, potassium thiocyanate, and sodium
azide. Sodium azide is a moderately hard nucleophile
occupying an intermediate position between arenesul-
finic acids and hydrogen chloride [1]. In reactions with
N-substituted 1,4-quinone imines having free position
2 and/or 6, sodium azide behaves similarly to hydro-
gen chloride, i.e., the reaction follows the 1,4-addition
scheme [2–6]. 1,2-Addition products were isolated in
reactions of N-arenesulfonyl(acyl)-2,3,5,6-tetrachloro-
(or 2,6-dichloro-3,5-dimethyl)-1,4-benzoquinone
imines [5–6], whereas N-arenesulfonyl-2,3,5,6-tetra-
chloro(or 2,6-dichloro-3,5-dimethyl)-1,4-benzoqui-
none imines also reacted via nucleophilic substitution
of the chlorine atoms in positions 2 and 6 by azido
groups [5]. N-Arylcarbamoyl-1,4-benzoquinone imines
synthesized previously [7] may be expected to give
rise to new paths in the reaction with sodium azide, for
these substrates are classed, on the one hand, with
N-substituted 1,4-benzoquinone imines and, on the
other, with urea derivatives.
The reactions of N-arylcarbamoyl-1,4-benzoqui-
none imines I–VIII with sodium azide were carried
out in acetic acid using 2 equiv of the nucleophile. As
a result, we isolated the corresponding 1,4-addition
products, 1-(3-azido-4-hydroxyphenyl)-3-arylureas
IX–XV (Scheme 1). N-Arylcarbamoyl-2,6-dimethyl-
1,4-benzoquinone imines VIIIa and VIIIb reacted
with sodium azide to give only the reduction products,
1-(4-hydroxy-3,5-dimethylphenyl)-3-arylureas which
were reported previously [7]. The quinone imine
Scheme 1.
O
OH
R1
R2
R4
R1
R2
N3
NaN3, AcOH
R3
R3
N
NHY
HN
NHY
O
O
Ia, Ib, IIa, IIb, IIIa, IIIc, IIId, IVa, IVb
Va, VIa, VIIa, VIIb, VIIIa, VIIIb
IXa, IXb, Xa, Xb, XIa, XIc, XId
XIIa, XIIb, XIIIa, XIVa, XVa, XVb
I, R1 = R2 = R3 = R4 = H; II, R1 = Me, R2 = R3 = R4 = H; III, R1 = R2 = Me, R3 = R4 = H; IV, R1 = R3 = Me, R2 = R4 = H; V, R1 =
i-Pr, R3 = Me, R2 = R4 = H; VI, R1 = Me, R3 = i-Pr, R2 = R4 = H; VII, R1 = R4 = H, R2 = R3 = Me; VIII, R1 = R4 = Me, R2 = R3 = H;
IX, R1 = R2 = R3 = H; X, R1 = Me, R2 = R3 = H; XI, R1 = R2 = Me, R3 = H; XII, R1 = R3 = Me, R2 = H; XIII, R1 = i-Pr, R2 = H, R3 =
Me; XIV, R1 = Me, R2 = H, R3 = i-Pr; XV, R1 = H, R2 = R3 = Me; XVI, Y=Ph (a), 4-MeC6H4 (b), 3-MeC6H4 (c), 3-ClC6H4 (d).
346

REACTION OF N-ARYLCARBAMOYL-1,4-BENZOQUINONE IMINES
347
reduction products were present in the reaction mix-
tures in almost all cases. Pure 1-(3-azido-4-hydroxy-
phenyl)-3-arylureas IX–XI and XV were isolated by
successive recrystallizations, but we failed to separate
product mixtures obtained from 2,5-dialkyl-substituted
quinone imines IV–VI, and the structure of com-
pounds XII–XIV was determined on the basis of
1H NMR and IR data.
acid. Presumably, the redox potential of compounds
IX–XV is higher than that of N-arenesulfonyl analogs.
According to published data, N-arenesulfonyl-2,6-
dichloro-3,5-dimethyl(or 2,3,5,6-tetrachloro)-1,4-ben-
zoquinone imines possessing an activated sterically
strained C=N bond can react with sodium azide along
two pathways. The reaction at room temperature fol-
lows the 1,2-addition pattern, and subsequent C2→C4
migration of the azido group is possible with simulta-
neous replacement of the halogen atom in position 2 of
the quinoid fragment by azido group. When the
reaction is carried out at elevated temperature, both
halogen atoms in positions 2 and 6 are replaced by
azido groups [5].
1
Compounds Xa and Xb displayed in the H NMR
spectra two doublets from 2-H (δ 6.85–6.87 ppm) and
6-H (δ 7.19 ppm), and the spectra of XI–XV contained
a singlet at δ 6.60–7.24 ppm from the aromatic proton
in the aminophenol fragment. In the IR spectra of the
addition products we observed an absorption band at
2110–2180 cm–1, which is typical of stretching vibra-
tions of azido group.
In continuation of our studies on the reactivity of
1,4-benzoquinone imines with sterically shielded nitro-
gen atom and activated sterically strained C=N bond
[5, 8], N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-
benzoquinone imines XVIIIa and XVIIIb were
reacted with sodium azide at a reactant ratio of 1:2 in
acetic acid at room temperature. These reactions
afforded N-arylcarbamoyl-2,6-diazido-3,5-dimethyl-
1,4-benzoquinone imines XIXa and XIXb (Scheme 3).
1-(3-Azido-4-hydroxyphenyl)-3-arylureas XIa and
XIIb were oxidized to N-arylcarbamoyl-2-azido-1,4-
benzoquinone imines XVI and XVII, respectively,
with lead tetraacetate in acetic acid (Scheme 2).
Insofar as we failed to isolate compound XIIb as
individual substance (it contained the corresponding
reduced form), its oxidation and subsequent recrystal-
lization gave a product which also contained two com-
pounds, 1-(2-azido-2,5-imethyl-4-oxocyclohexa-2,5-
dien-1-ylidene)-3-(4-methylphenyl)urea (XVII) and
initial quinone imine IVb which could not be
separated.
1
The H NMR spectra of quinone imines XIXa and
XIXb contained a singlet from protons in the two
methyl groups, which indicated their equivalence. In
the IR spectrum of XIXa and XIXb, characteristic
absorption band due to stretching vibrations of the
azido group was located at 2110–2180 cm–1. The ele-
mental analyses and Beilstein test showed the absence
of halogen in molecules XIXa and XIXb. The product
structure suggests that nucleophilic substitution of
chlorine in positions 2 and 6 of the quinoid fragment in
N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-benzo-
quinone imines by azido groups is preferred over
1,2-addition.
Scheme 2.
O
R1
R2
N3
[O]
XIa, XIIb
R3
N
NHY
O
Scheme 3.
XVI, XVII
O
O
XVI, R1 = R2 = Me, R3 = H, Y = Ph; XVII, R1 = R3 = Me,
Cl
Cl
N3
N3
R2 = H, Y = 4-MeC6H4.
2NaN3, AcOH
–2NaCl
We previously found [5] that N-substituted 2-azido-
4-aminophenols (1,4-addition products of sodium
azide to N-substituted 1,4-benzoquinone imines) on
heating in acetic acid undergo intramolecular redox
transformation with elimination of gaseous nitrogen
and formation of N-substituted 2-amino-1,4-benzo-
quinone imines. However, no intramolecular redox
reaction typical of N-arenesulfonyl derivatives was
observed even on prolonged heating of 1-(3-azido-4-
hydroxyphenyl)-3-arylureas IX–XV in boiling acetic
Me
Me
Me
Me
N
NHY
N
NHY
O
O
XVIIIa, XVIIIb
XIXa, XIXb
Y= Ph (a), 4-MeC6H4 (b).
In summary, we have found that N-arylcarbamoyl-
1,4-benzoquinone imines having at least one free ortho
position with respect to the carbonyl carbon atom react
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KONOVALOVA et al.
348
with sodium azide exclusively according to the 1,4-ad-
dition pattern to produce 1-(3-azido-4-hydroxyphenyl)-
3-arylureas which do not undergo intramolecular
oxidation–reduction. The reaction of N-arylcarbamoyl-
2,6-dichloro-3,5-dimethyl-1,4-benzoquinone imines
with sodium azide follows only nucleophilic substitu-
tion mechanism with formation of N-arylcarbamoyl-
2,6-diazido-3,5-dimethyl-1,4-benzoquinone imines,
which may be due to lower reactivity of the activated
sterically strained C=N bond in N-arylcarbamoyl
derivatives XVIII as compared to N-arenesulfonyl
analogs.
(1H, 4′-H), 7.41 br.s (1H, 2′-H). Found, %: N 10.48,
10.65. C16H16N2O2. Calculated, %: N 10.44.
1-(3-Chlorophenyl)-3-(2,3-dimethyl-4-oxocyclo-
hexa-2,5-dien-1-ylidene)urea (IIId). Yield 54%,
1
mp 162–164°C (from AcOH). H NMR spectrum
(CDCl3), δ, ppm: 2.05 s (3H, 2-Me), 2.16 s (3H,
3-Me), 6.52 d (1H, 5-H, J = 10.2 Hz), 7.12 d (1H,
6′-H, J = 8.1 Hz), 7.21 d (1H, 6-H), 7.24–7.29 t (1H,
5′-H), 7.31 d (1H, 4′-H), 7.36 br.s (1H, 2′-H), 7.68 br.s
(1H, NH). Found, %: N 9.78, 9.90. C15H13ClN2O2.
Calculated, %: N 9.70.
1-(2,5-Dimethyl-4-oxocyclohexa-2,5-dien-1-
ylidene)-3-(4-methylphenyl)urea (IVb). Yield 63%,
EXPERIMENTAL
1
mp 177–179°C (from AcOH). H NMR spectrum
(CDCl3), δ, ppm: 1.99 br.s (3H, 2-Me), 2.18 br.s (3H,
5-Me), 2.34 s (3H, 4-MeC6H4), 6.54 br.s (1H, 3-H),
7.00 br.s (1H, NH), 7.10 br.s (1H, 6-H), 7.17 d (2H,
3′-H, 5′-H, J = 8.1 Hz), 7.45 d (2H, 2′-H, 6′-H, J =
8.1 Hz). Found, %: N 10.48, 10.51. C15H15N2O2. Cal-
culated, %: N 10.97.
1
The H NMR spectra were recorded on a Varian
VXR-300 instrument (300 MHz) using tetramethyl-
silane as internal reference. Quinone imines I–VIII
and XVIII were synthesized according to the proce-
dures described in [7, 9].
1-(4-Methylphenyl)-3-(4-oxocyclohexa-2,5-dien-
Reaction of 1,4-benzoquinone imines I–VIII and
XVIII with sodium azide (general procedure).
Sodium azide, 0.01 mol (0.02 mol in the reactions with
XVIII) was added to a solution of 0.005 mol of the
corresponding quinone imine in 10 mL of acetic acid.
The precipitate was filtered off, washed with water,
and dried. Compounds XI and XII were recrystallized
from ethyl acetate, and IX, X, XIII, and XIV, from
ethyl acetate–heptane (7:3).
1-ylidene)urea (Ib). Yield 66%, mp 115–117°C (from
1
AcOH). H NMR spectrum (CDCl3), δ, ppm: 2.33 s
(3H, 4-MeC6H4), 6.55–6.57 d.d (1H, 3-H, J =
10.2 Hz), 6.65–6.69 d.d (1H, 5-H, J = 10.2 Hz), 7.07–
7.11 d.d (1H, 2-H, J = 2.4 Hz), 7.15 d (2H, 3′-H, 5′-H,
J = 8.1 Hz), 7.36 br.s (1H, NH), 7.41–7.44 d.d (1H,
6-H), 7.43 d (2H, 2′-H, 6′-H, J = 8.1 Hz). Found, %:
N 11.35, 11. 59. C13H11N2O2. Calculated, %: N 11.66.
1-(3-Methyl-4-oxocyclohexa-2,5-dien-1-ylidene)-
1-(3-Azido-4-hydroxyphenyl)-3-phenylurea
1
3-(4-methylphenyl)urea (IIb). Yield 61%, mp 134–
(IXa). Yield 67%, mp 110–112°C. H NMR spectrum
1
135°C (from AcOH). H NMR spectrum (CDCl3), δ,
(DMSO-d6), δ, ppm: 6.68 d (1H, 6-H, J = 8.7 Hz),
7.03 br.s (1H, 2-H), 7.22 d.d (1H, 5-H, J = 1.8,
8.7 Hz), 6.97–7.51 m (5H, Ph), 8.33 s (1H, N1H),
8.53 s (1H, N3H), 9.08 s (1H, OH). Found, %: N 25.03,
26.11. C13H11N5O2. Calculated, %: N 26.01.
ppm: Z isomer: 2.04 d (3H, 2-Me, J = 0.9 Hz), 2.34 s
(3H, 4-MeC6H4), 6.69 d (1H, 5-H, J = 9.9 Hz), 7.03–
7.07 d.d (1H, 2-H, J = 2.1, 9.9 Hz), 7.17 d (2H, m-H,
J = 8.1 Hz), 7.19 br.s (1H, 6-H), 7.22 br.s (1H, NH),
7.45 d (2H, o-H, J = 8.1 Hz); E isomer: 2.09 d (3H,
2-Me, J = 0.9 Hz), 2.34 s (3H, 4-MeC6H4), 6.57 d (1H,
5-H, J = 9.9 Hz), 6.93 br.s (1H, 2-H), 7.17 d (2H, 3′-H,
5′-H, J = 8.1 Hz), 7.24 br.s (1H, NH), 7.38–7.42 d.d
(1H, 6-H, J = 2.1, 9.9 Hz), 7.45 d (2H, 2′-H, 6′-H, J =
8.1 Hz). Found, %: N 11.25, 11.45. C14H13N2O2. Cal-
culated, %: N 11.66.
1-(3-Azido-4-hydroxyphenyl)-3-(4-methyl-
phenyl)urea (IXb). Yield 80%, mp 105–107°C.
1H NMR spectrum (DMSO-d6), δ, ppm: 2.23 s (3H,
4-MeC6H4), 6.67 d (1H, 6-H, J = 8.7 Hz), 7.06 d (2H,
2′-H, 6′-H, J = 8.4 Hz), 7.07 br.s (1H, 2-H), 7.20 d.d
(1H, 5-H, J = 1.8, 8.7 Hz), 7.31 d (2H, 3′-H, 5′-H, J =
8.4 Hz), 8.31 s (1H, N1H), 8.46 s (1H, N3H), 9.06 br.s
(1H, OH). Found, %: N 24.64, 24.79. C14H13N5O2.
Calculated, %: N 24.72.
1-(3-Azido-4-hydroxy-5-methylphenyl)-
3-phenylurea (Xa). Yield 90%, mp 134–135°C.
1H NMR spectrum (DMSO-d6), δ, ppm: 2.14 s (3H,
5-Me), 6.87 d (1H, 2-H, J = 1.8 Hz), 7.19 d (1H, 6-H,
J = 1.8 Hz), 6.93–7.45 m (5H, Ph), 8.49 s (1H, N1H),
1-(2,3-Dimethyl-4-oxocyclohexa-2,5-dien-1-
ylidene)-3-(3-methylphenyl)urea (IIIc). Yield 47%,
1
mp 154–155°C (from AcOH). H NMR spectrum
(CDCl3), δ, ppm: 2.04 s (3H, 2-Me), 2.17 s (3H,
3-Me), 2.36 s (3H, 3-MeC6H4), 6.51 d (1H, 5-H, J =
10.2 Hz), 6.96 d (1H, 6′-H, J = 7.5 Hz), 7.16 br.s (1H,
NH), 7.20–7.25 t (1H, 5′-H), 7.22 d (1H, 6-H), 7.31 d
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REACTION OF N-ARYLCARBAMOYL-1,4-BENZOQUINONE IMINES
349
8.60 s (1H, N3H), 8.66 br.s (1H, OH). Found, %:
N 24.59, 24.67. C14H13N5O2. Calculated, %: N 24.72.
(DMSO-d6), δ, ppm: 1.13 d [6H, CH(CH3)2], 2.07 s
(3H, 2-Me), 3.19–3.28 m [1H, CH(CH3)2], 7.22 s (1H,
6-H), 6.91–7.44 m (5H, Ph), 7.82 s (1H, N1H), 8.79 s
(1H, N3H), 8.91 br.s (1H, OH).
1-(3-Azido-4-hydroxy-5-methylphenyl)-
3-(4-methylphenyl)urea (Xb). Yield 81%, mp 129–
1
1-(3-Azido-4-hydroxy-2-isopropyl-5-methyl-
130°C. H NMR spectrum (DMSO-d6), δ, ppm: 2.14 s
1
phenyl)-3-phenylurea (XIVa). H NMR spectrum
(3H, 5-Me), 2.24 s (3H, 4-MeC6H4), 6.85 d (1H, 2-H,
J = 2.1 Hz), 7.07 d (2H, 2′-H, 6′-H, J = 8.4 Hz), 7.19 d
(1H, 6-H, J = 2.1 Hz), 7.32 d (2H, 3′-H, 5′-H, J =
8.4 Hz), 8.42 s (1H, N1H), 8.47 s (1H, N3H), 8.65 br.s
(1H, OH). Found, %: N 23.61, 23.85. C15H15N5O2.
Calculated, %: N 23.56.
(DMSO-d6), δ, ppm: 1.25 d [6H, CH(CH3)2], 2.06 s
(3H, 5-Me), 3.19–3.28 m [1H, CH(CH3)2], 7.24 s (1H,
6-H), 6.88–7.47 m (5H, Ph), 7.64 s (1H, N1H), 8.70 s
(1H, N3H), 9.67 br.s (1H, OH).
1-(3-Azido-4-hydroxy-2,6-dimethylphenyl)-
3-phenylurea (XVa). Yield 86%, mp 136–137°C
(from EtOAc). 1H NMR spectrum (DMSO-d6), δ, ppm:
2.04 s (3H, 6-Me), 2.09 s (3H, 2-Me), 6.61 s (1H,
5-H), 6.89–7.43 m (5H, Ph), 7.53 s (1H, N1H),
8.70 br.s (1H, N3H), 10.12 br.s (1H, OH). Found, %:
N 23.64, 23.87. C15H15N5O2. Calculated, %: N 23.56.
1-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
3-phenylurea (XIa). Yield 76%, mp 142–144°C.
1H NMR spectrum (DMSO-d6), δ, ppm: 2.09 s (3H,
3-Me), 2.12 s (3H, 2-Me), 7.23 s (1H, 6-H), 6.91–
7.46 m (5H, Ph), 7.96 s (1H, N1H), 8.93 s (1H, N3H),
9.35 br.s (1H, OH). Found, %: N 23.45, 23.59.
C15H15N5O2. Calculated, %: N 23.56.
1-(3-Azido-4-hydroxy-2,6-dimethylphenyl)-
3-(4-methylphenyl)urea (XVb). Yield 84%, mp 110–
1-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
1
113°C (from EtOAc). H NMR spectrum (DMSO-d6),
3-(3-methylphenyl)urea (XIc). Yield 75%, mp 167–
1
δ, ppm: 2.04 s (3H, 6-Me), 2.08 s (3H, 2-Me), 2.23 s
(3H, 3-MeC6H4), 6.60 s (1H, 5-H), 7.03 d (2H, 2′-H,
6′-H, J = 8.1 Hz), 7.31 d (2H, 3′-H, 5′-H, J = 8.1 Hz),
7.65 s (1H, N1H), 8.73 br.s (1H, N3H), 11.02 br.s (1H,
OH). Found, %: N 22.41, 22.72. C16H17N5O2. Calculat-
ed, %: N 22.49.
169°C. H NMR spectrum (DMSO-d6), δ, ppm: 2.09 s
(3H, 3-Me), 2.26 s (3H, 3-MeC6H4), 2.11 s (3H,
2-Me), 6.74–6.76 d.d (1H, 4′-H), 7.10–7.15 t (1H,
6′-H), 7.20–7.22 d.d (1H, 5′-H), 7.22 s (1H, 6-H),
7.30 br.s (1H, 2′-H), 8.04 s (1H, N1H), 8.96 s (1H,
N3H), 9.99 br.s (1H, OH). Found, %: N 22.38, 22.56.
C16H17N5O2. Calculated, %: N 22.49.
1-(3,5-Diazido-2,6-dimethyl-4-oxocyclohexa-2,5-
dien-1-ylidene)-3-phenylurea (XIXa). Yield 35%,
1-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
1
mp 141–142°C (from EtOAc). H NMR spectrum
3-(3-chlorophenyl)urea (XId). Yield 85%, mp 181–
(DMSO-d6), δ, ppm: 2.12 s (6H, 2-Me, 6-Me),
7.07 br.s (1H, NH), 7.12–7.49 m (5H, Ph). Found, %:
N 33.35, 33.67. C15H12N8O2. Calculated, %: N 33.32.
1
182°C. H NMR spectrum (DMSO-d6), δ, ppm: 2.07 s
(3H, 3-Me), 2.10 s (3H, 2-Me), 6.89–6.92 d.d (1H,
4′-H), 7.22 s (1H, 6-H), 7.20–7.25 t (1H, 6′-H), 7.34–
7.37 d.d (1H, 5′-H), 7.74 q (1H, 2′-H), 8.96 s (1H,
N1H), 9.04 s (1H, N3H), 10.54 br.s (1H, OH). Found,
%: N 21.17, 21.52. C15H14ClN5O2. Calculated, %:
N 21.11.
1-(3,5-Diazido-2,6-dimethyl-4-oxocyclohexa-2,5-
dien-1-ylidene)-3-(4-methylphenyl)urea (XIXb).
1
Yield 20%, mp 140–141°C (from EtOAc). H NMR
spectrum (CDCl3), δ, ppm: 2.12 s (6H, 2-Me, 6-Me),
2.33 s (3H, 4-MeC6H4), 6.91 br.s (1H, NH), 7.15 d
(2H, 2′-H, 6′-H, J = 8.1 Hz), 7.36 d (2H, 3′-H, 5′-H,
J = 8.1 Hz). Found, %: N 32.11, 32.37. C16H14N8O2.
Calculated, %: N 31.98.
1-(3-Azido-4-hydroxy-2,5-dimethylphenyl)-
1
3-phenylurea (XIIa). H NMR spectrum (DMSO-d6),
δ, ppm: 2.06 s (3H, 5-Me), 2.15 s (3H, 2-Me), 7.16 s
(1H, 6-H), 6.91–7.44 m (5H, Ph), 7.77 s (1H, N1H),
8.77 s (1H, N3H), 9.01 br.s (1H, OH).
Oxidation of compounds XIa and XIIb (general
procedure). A suspension of 0.01 mol of compound
XIa or XIIb in 2–3 mL of glacial acetic acid was
cooled in an ice bath, 0.011 mol of lead tetraacetate
was added, and the mixture was stirred for 30 min until
bright orange crystalline material was formed. A few
drops of ethylene glycol were added, the mixture was
stirred for 5 min, and the precipitate was filtered off
and recrystallized from benzene.
1-(3-Azido-4-hydroxy-2,5-dimethylphenyl)-
1
3-(4-methylphenyl)urea (XIIb). H NMR spectrum
(DMSO-d6), δ, ppm: 2.06 s (3H, 5-Me), 2.16 s (3H,
2-Me), 2.23 s (3H, 4-MeC6H4), 7.03 d (2H, 2′-H, 6′-H,
J = 8.1 Hz), 7.16 s (1H, 6-H), 7.31 d (2H, 3′-H, 5′-H,
J = 8.1 Hz), 7.72 s (1H, N1H), 8.66 s (1H, N3H),
8.99 br.s (1H, OH).
1-(3-Azido-4-hydroxy-5-isopropyl-2-methyl-
1-(5-Azido-2,3-dimethyl-4-oxocyclohexa-2,5-dien-
1-ylidene)-3-phenylurea (XVI). Yield 56%, mp 115–
1
phenyl)-3-phenylurea (XIIIa). H NMR spectrum
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 3 2014

KONOVALOVA et al.
350
1
2. Adams, R. and Reifshneider, W., Bull. Soc. Chim. Fr.,
116°C. H NMR spectrum (CDCl3), δ, ppm: 2.09 s
(3H, 2-Me), 2.20 s (3H, 3-Me), 6.72 s (1H, 5-H),
7.04 br.s (1H, NH), 7.13–7.54 m (5H, Ph). Found, %:
N 23.53, 23.88. C15H13N5O2. Calculated, %: N 23.72.
1958, no. 1, p. 23.
3. Adams, R. and Blomstrom, D.C., J. Am. Chem. Soc.,
1953, vol. 75, p. 3405.
4. Avdeenko, A.P. and Marchenko, I.L., Russ. J. Org.
1-(3-Azido-2,5-dimethyl-4-oxocyclohexa-2,5-
dien-1-ylidene)-3-(4-methylphenyl)urea (XVII).
Yield 28%, mp 124–126°C. H NMR spectrum
(CDCl3), δ, ppm: 2.03 d (3H, 2-Me), 2.10 s (3H,
5-Me), 2.34 s (3H, 4-MeC6H4), 6.99 br.s (1H, NH),
7.12 s (1H, 3-H), 7.17 d (2H, 2′-H, 6′-H, J = 8.1 Hz),
7.44 d (2H, 3′-H, 5′-H, J = 8.1 Hz). Found, %:
N 22.31, 22.72. C16H15N5O2. Calculated, %: N 22.64.
Chem., 2006, vol. 42, p. 873.
5. Avdeenko, A.P., Menafova, Yu.V., and Zhukova, S.A.,
1
Russ. J. Org. Chem., 1998, vol. 34, p. 210.
6. Avdeenko, A.P. and Menafova, Yu.V., Russ. J. Org.
Chem., 2006, vol. 42, p. 403.
7. Avdeenko, A.P., Konovalova, S.A., Sergeeva, A.G.,
Zubatyuk, R.I., Palamarchuk, G.V., and Shishkin, O.V.,
Russ. J. Org. Chem., 2008, vol. 44, p. 1765.
8. Menafova, Yu.V., Cand. Sci. (Chem.) Dissertation,
Dnepropetrovsk, 1999.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 3 2014