Reaction of N-phenyl(benzylidene, phenoxy)acetyl-1,4-benzoquinone imines with sodium azide

Article abstract of DOI:10.1134/S1070428014030087

N-Phenyl(benzylidene, phenoxy)acetyl-1,4-benzoquinone imines reacted with sodium azide to give the corresponding 1,4-addition products, N-(4-hydroxyphenyl) carboxamides. Quantum chemical calculations showed that the initial step in the examined reaction i

Full text of DOI:10.1134/S1070428014030087

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 3, pp. 351–354. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © S.A. Konovalova, A.P. Avdeenko, V.M. Vasil’eva, S.A. Goncharova, 2014, published in Zhurnal Organicheskoi Khimii, 2014,
Vol. 50, No. 3, pp. 362–365.
Reaction of N-Phenyl(benzylidene, phenoxy)acetyl-
1,4-benzoquinone Imines with Sodium Azide
S. A. Konovalova, A. P. Avdeenko, V. M. Vasil’eva, and S. A. Goncharova
Donbass State Engineering Academy, ul. Shkadinova 72, Kramatorsk, 84313 Ukraine
e-mail: chimist@dgma.donetsk.ua
Received October 25, 2013
Abstract—N-Phenyl(benzylidene, phenoxy)acetyl-1,4-benzoquinone imines reacted with sodium azide to give
the corresponding 1,4-addition products, N-(4-hydroxyphenyl) carboxamides. Quantum chemical calculations
showed that the initial step in the examined reaction is addition of azide ion to neutral quinone imine molecule.
DOI: 10.1134/S1070428014030087
1
It was found previously that N-substituted 1,4-ben-
zoquinone imines possessing at least one free ortho
position with respect to the carbonyl carbon atom react
with sodium azide according to the 1,4-addition pattern
[1–5]. Products resulting from nucleophilic substitu-
tion of chlorine in positions 2 and 6 of the quinoid ring
by azido group and 1,2-addition products were isolated
only in the reactions with N-arylsulfonyl(acyl)-2,3,5,6-
tetrachloro-(2,6-dichloro-3,5-dimethyl)-1,4-benzoqui-
none imines [2, 3]. The mechanism of this reaction
was not studied previously.
In the H NMR spectra of IV–VI we observed
signals at δ 8.88–9.53 and 9.29–9.52 ppm due to NH
and OH protons, respectively. Protons of the CH2 and
OCH2 groups in V and VI gave singlets at δ 3.59–3.61
and 4.66–4.69 ppm, respectively, and signals from the
CH=CH fragment of IV appeared as two doublets in
the region δ 6.88–7.53 ppm. The IR spectra of IV–VI
displayed a strong narrow peak in the region 2180–
2110, which is typical of azido group, and absorption
bands at 3350–3200 and 3430–3380 cm–1 due to
stretching vibrations of the NH and OH groups.
In the present work we examined reactions of
previously synthesized quinone imines I–III [6] with
sodium azide at a reactant ratio of 1:2 and mechanism
of the process. The reactions were carried out in acetic
acid at room temperature (reaction time 1–2 h), and
the products were exclusively azido-substituted amino
phenols IV–VI formed as a result of 1,4-addition of
azide ion (Scheme 1). The reactions with compounds
Ia, Ib, IIa, IIb, and IIIa–IIIc were accompanied by
reduction of the initial quinone imines.
Compounds IV–VI remained unchanged on heating
in boiling acetic acid, i.e., they did not undergo intra-
molecular redox transformation observed for azido
derivatives of N-arylsulfonyl-1,4-benzoquinone imines
[3]. Presumably, such behavior is determined by high
redox potential of IV–VI, by analogy with N-aroyl- [2]
and N-arylcarbamoyl derivatives [7].
Taking into account that the mechanism of reaction
of N-substituted 1,4-benzoquinone imines was not
studied previously, we analyzed possible reaction paths
with the aid of quantum chemical calculations. Insofar
as the reactions were carried out in acetic acid, first of
all it was necessary to elucidate the structure of react-
ing nucleophile species. The pKa value of hydrazoic
acid is 4.59, which is close to pKa of acetic acid (4.75)
[8]; therefore, both azide ion and neutral hydrazoic
acid molecule may be present in the system sodium
azide–acetic acid. According to quantum chemical cal-
culations, the equilibrium constant for the transforma-
Scheme 1.
O
OH
R1
R2
R1
R2
N3
NaN3
R3
R3
N
HN
C(O)X
C(O)X
Ia–Ic, IIa–IIc, IIIa–IIIc
IVa–IVc, Va–Vc, VIa–VIc
tion AcOH + N3–
HN3 + AcO– (calculated by the
I, IV, X = PhCH=CH; II, V, X = PhCH2; III, VI, X =
PhOCH2; R1 = R2 = Me, R3 = H (a); R1 = R3 = Me, R2 =
H (b); R1 = H, R2 = R3 = Me (c).
Gibbs equation [9]) is 5.2×10–6, i.e., the reactive
species is most likely to be azide ion.
351

KONOVALOVA et al.
352
follows from the obtained data, the most probable
Analysis of published data showed that the initial
initial step involves direct addition of azide ion to
neutral molecule IId with formation of intermediate C,
since the energy of the system comprising intermediate
C and anions N3– and AcO– is the lowest (Scheme 2;
see figure). In the second step, proton addition to
the nitrogen atom in C gives intermediate E whose
aromatization finally yields 1,4-addition product Vd.
In summary, we have found that N-acyl-1,4-benzo-
quinone imines react with sodium azide via addition
of azide ion to neutral quinone molecule, protona-
step in the reactions of quinone imines with nucleo-
phile may be protonation of the substrate at the oxygen
or nitrogen atom, addition of anionic nucleophile to
neutral substrate molecule, and electron transfer with
formation of quinone imine radical anion. In order to
reveal which of the above reaction paths is most prob-
able, we performed quantum chemical optimization of
the corresponding intermediates A–D in the reaction
with N-(4-oxocyclohexa-2,5-dien-1-ylidene)-2-phenyl-
acetamide (IId) as model substrate (Scheme 2). As
Scheme 2.
OH
+
N3 +
AcO–
N
Ph
O
A
E = –2988928.71 kJ/mol
O
+
N3 +
AcO–
HN
O
N
Ph
O
B
+ N3 + AcOH
E = –2988972.46 kJ/mol
O
O
Ph
N3
N3
O
H
H
IId
E = –2989521.13 kJ/mol
+ AcOH
+ AcO–
Vd
N
HN
Ph
Ph
O
O
C
E
E = –2989558.70 kJ/mol
E = –2989518.73 kJ/mol
·
O
·
+
N3
+
AcOH
N
Ph
O
D
E = –2989477.76 kJ/mol
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 3 2014

REACTION OF N-PHENYL(BENZYLIDENE, PHENOXY)ACETYL-1,4-BENZOQUINONE
353
E, kJ/mol
tion of quinone imine anion thus formed at the nitro-
gen atom, and subsequent aromatization to give
1,4-addition products.
A
B
–2988900
–2989000
–2989100
–2989200
–2989300
–2989400
–2989500
–2989600
EXPERIMENTAL
1
The H NMR spectra were measured on a Varian
VXR-300 instrument at 300 MHz using DMSO-d6 as
solvent and TMS as reference. The IR spectra were
recorded on a UR-20 spectrometer from samples
pelleted with KBr. The progress of reactions and the
purity of products were monitored by TLC on Silufol
UV-254 plates; samples were applied from solutions in
CHCl3; plates were eluted with benzene–hexane
(10:1), and spots were visualized under UV light.
D
C
IId
E
Quantum chemical calculations were performed
with the aid of Firefly QC software package [10],
which is based in part on the GAMESS (US) code
[11]. The molecular structures were simulated in terms
of the density functional theory using B3LYP func-
tional and standard 6-31+G(d) basis set.
N-(4-Oxocyclohexa-2,5-dien-1-ylidene)-2-phenyl-
(phenoxy, benzylidene)acetamides Ia–Ic, IIa–IIc, and
IIIa–IIIc were prepared by oxidation of the corre-
sponding N-(4-hydroxyphenyl) carboxamides with
lead tetraacetate in acetic acid according to the proce-
dure described in [6]; their physicochemical properties
were consistent with those given in [6].
Reaction of quinone imines I–III with sodium
azide (general procedure). A solution of 4 mmol of
sodium azide in a small amount of glacial acetic acid
was added in one portion at room temperature to
a solution of 2 mmol of quinone imine Ia–Ic, IIa–IIc,
or IIIa–IIIc in 20 mL of glacial acetic acid. The solu-
tion turned red–brown and then (after 1–2 h) changed
to light brown. If no solid separated from the reaction
mixture, it was poured into a mixture of water with ice
under vigorous stirring. The precipitate was filtered
off, washed with water, dried, and recrystallized from
benzene–hexane (1:2).
N-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
3-phenylprop-2-enamide (IVa). Yield 89%, mp 159–
160°C. 1H NMR spectrum, δ, ppm: 2.07 s (3H, 3-Me),
2.12 s (3H, 2-Me), 6.91 d (1H, CH=CH, J = 16.2 Hz),
7.06 s (1H, 6-H), 7.42–7.63 m (5H, Ph), 7.53 d (1H,
CH=CH, J = 15.6 Hz), 8.88 br.s (1H, NH), 9.50 br.s
(1H, OH). Found, %: N 18.78, 18.53. C15H12N4O2.
Calculated, %: N 18.17.
Energy diagram of the reaction of N-phenylacetyl-1,4-benzo-
quinone imine (IId) with sodium azide.
7.11 s (1H, 6-H), 7.39–7.63 m (5H, Ph), 7.53 d (1H,
CH=CH, J = 15.9 Hz), 9.35 br.s (1H, NH), 9.52 br.s
(1H, OH). Found, %: N 18.10, 18.51. C17H16N4O2.
Calculated, %: N 18.17.
N-(3-Azido-4-hydroxy-2,6-dimethylphenyl)-
3-phenylprop-2-enamide (IVc). Yield 33%, mp 157–
158°C. 1H NMR spectrum, δ, ppm: 1.99 s (3H, 6-Me),
2.03 s (3H, 2-Me), 6.63 br.s (1H, 5-H), 6.85 d (1H,
CH=CH, J = 15.9 Hz), 7.41–7.63 m (5H, Ph), 7.53 d
(1H, CH=CH, J = 16.2 Hz), 9.34 br.s (1H, NH),
9.55 br.s (1H, OH). Found, %: N 18.03, 18.74.
C17H16N4O2. Calculated, %: N 18.17.
N-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
2-phenylacetamide (Va). Yield 70%, mp 124–125°C.
1H NMR spectrum, δ, ppm: 2.08 s (3H, 3-Me), 2.15 s
(3H, 2-Me), 3.61 s (2H, CH2), 6.83 s (1H, 6-H), 7.25–
7.34 m (5H, Ph), 9.49 br.s (1H, NH), 9.51 br.s (1H,
OH). Found, %: N 19.04, 19.47. C14H12N4O2. Calculat-
ed, %: N 18.91.
N-(3-Azido-4-hydroxy-2,5-dimethylphenyl)-
2-phenylacetamide (Vb). Yield 54%, mp 169–170°C.
1H NMR spectrum, δ, ppm: 2.04 s (3H, 5-Me), 2.14 s
(3H, 2-Me), 3.60 s (2H, CH2), 7.01 s (1H, 6-H), 7.24–
7.35 m (5H, Ph), 9.34 br.s (1H, NH), 9.51 br.s (1H,
OH). Found, %: N 19.24, 19.78. C16H16N4O2. Calculat-
ed, %: N 18.91.
N-(3-Azido-4-hydroxy-2,6-dimethylphenyl)-
2-phenylacetamide (Vc). Yield 60%, mp 159–160°C.
1H NMR spectrum, δ, ppm: 1.91 s (3H, 6-Me), 1.95 s
(3H, 2-Me), 3.59 s (2H, CH2), 6.57 s (1H, 5-H), 7.24–
7.34 m (5H, Ph), 9.28 br.s (1H, NH), 9.45 br.s (1H,
OH). Found, %: N 19.07, 19.62. C16H16N4O2. Calculat-
ed, %: N 18.91.
N-(3-Azido-4-hydroxy-2,5-dimethylphenyl)-
3-phenylprop-2-enamide (IVb). Yield 92%, mp 219–
220°C. 1H NMR spectrum, δ, ppm: 2.03 s (3H, 5-Me),
2.17 s (3H, 2-Me), 6.90 d (1H, CH=CH, J = 15.9 Hz),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 3 2014

KONOVALOVA et al.
354
2. Avdeenko, A.P. and Marchenko, I.L., Russ. J. Org.
Chem., 2006, vol. 42, p. 873.
3. Avdeenko, A.P., Menafova, Yu.V., and Zhukova, S.A.,
Russ. J. Org. Chem., 1998, vol. 34, p. 210.
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Chem., 2006, vol. 42, p. 403.
N-(5-Azido-4-hydroxy-2,3-dimethylphenyl)-
2-phenoxyacetamide (VIa). Yield 42%, mp 114–
1
115°C. H NMR spectrum, δ, ppm: 1.92 s (3H, 3-Me),
2.19 s (3H, 2-Me), 4.69 s (2H, OCH2), 6.91 s (1H,
6-H), 6.98–7.34 m (5H, Ph), 9.53 br.s (1H, NH),
9.69 br.s (1H, OH). Found, %: N 18.59, 18.15.
C13H10N4O3. Calculated, %: N 18.78.
5. Adams, R. and Reifschneider, W., Bull. Soc. Chim. Fr.,
1958, p. 25.
N-(3-Azido-4-hydroxy-2,5-dimethylphenyl)-2-
phenoxyacetamide (VIb). Yield 75%, mp 163–164°C.
1H NMR spectrum, δ, ppm: 1.99 s (3H, 5-Me), 2.17 s
(3H, 2-Me), 4.66 s (2H, OCH2), 6.89 s (1H, 6-H),
6.99–7.35 m (5H, Ph), 9.04 br.s (1H, NH), 9.29 br.s
(1H, OH). Found, %: N 18.22, 17.97. C15H14N4O3.
Calculated, %: N 18.78.
6. Avdeenko, A.P., Konovalova, S.A., Vasil’eva, V.A.,
Shishkin, O.V., Palamarchuk, G.V., and Baumer, V.N.,
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8. Spravochnik khimika. Osnovnye svoistva organicheskikh
i neorganicheskikh soedinenii (Chemist’s Handbook.
Principal Properties of Organic and Inorganic Com-
pounds), Moscow: Gos. Nauch.-Tekhn. Izd. Khim.
Literatury, 1963, vol. 2, p. 352.
N-(3-Azido-4-hydroxy-2,6-dimethylphenyl)-2-
phenoxyacetamide (VIc). Yield 82%, mp 162–163°C.
1H NMR spectrum, δ, ppm: 1.94 s (3H, 2-Me), 1.99 s
(3H, 6-Me), 4.69 s (2H, OCH2), 6.59 s (1H, 5-H),
6.95–7.34 m (5H, Ph), 9.18 br.s (1H, NH), 9.30 br.s
(1H, OH). Found, %: N 18.35, 18.15. C15H14N4O3.
Calculated, %: N 18.78.
9. Gordon, A.J. and Ford, R.A., The Chemist’s Companion,
New York: Wiley, 1972.
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