2,4,5-triphenylimidazole as an indicator of intermediate formation of 2,3-diphenyl-2H-azirine in the synthesis of 1-vinyl-2,3-diphenylpyrrole from benzyl phenyl ketoxime and acetylene

Full text of DOI:10.1134/S0012500811020066

ISSN 0012ꢀ5008, Doklady Chemistry, 2011, Vol. 436, Part 2, pp. 43–45. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © O.V. Petrova, I.A. Ushakov, L.N. Sobenina, A.I. Mikhaleva, B.A. Trofimov, 2011, published in Doklady Akademii Nauk, 2011, Vol. 436, No. 6,
pp. 785–787.
CHEMISTRY
2,4,5ꢀTriphenylimidazole as an Indicator of Intermediate Formation
of 2,3ꢀDiphenylꢀ2 ꢀazirine in the Synthesis
H
of 1ꢀVinylꢀ2,3ꢀDiphenylpyrrole from Benzyl Phenyl Ketoxime
and Acetylene
O. V. Petrova, I. A. Ushakov, L. N. Sobenina, A. I. Mikhaleva, and Academician B. A. Trofimov
Received August 3, 2010
DOI: 10.1134/S0012500811020066
The assemblage of pyrrole ring from ketoximes and anes [8], and minor byproducts that, nonetheless, can
acetylenes in superbasic systems like KOH–DMSO provide valuable information on the reaction mechaꢀ
the Trofimov reaction) [1–3] attracts the growing nism.
(
interest of synthetic chemists because of its simplicity
and versatility, as well as the possibility to obtain in one
Recently, upon treatment of a reaction mixture obꢀ
preparative step pyrroles and
ketones and acetylenes, even avoiding preliminary
preparation of ketoximes [4, 5]. Depending on reacꢀ a KOH–DMSO system (130
tion conditions and initial reactant structures, other pressure, we isolated Nꢀbenzylbenzamide (
heterocyclic compounds are formed sometimes along [9], benzoic acid (55%), and 2,3,6ꢀtriphenylpyridine
with pyrroles, for example, pyridylpyrroles [6], carboꢀ
) (1.5%) [10], along with target compound (17%),
N
ꢀvinylpyrroles from tained in the synthesis of 1ꢀvinylꢀ2,3ꢀdiphenylpyrrole
) from benzyl phenyl ketoxime ( ) and acetylene in
С, 7 h) at atmospheric
) (12%)
(
2
1
°
3
(4
2
lines [7], 4ꢀmethyleneꢀ3ꢀoxaꢀ1ꢀazabicyclo[3.1.0]hexꢀ Scheme 1.
Ph
O
HC≡CH
Ph
KOH–DMSO
+
Ph
N
H
Ph
+ PhCOOH
NOH
130°C, 7 h
Ph
N
Ph
1
2
3
Ph
Ph
Ph
Ph
N
+
+
Ph
N
N
Ph
H
H
4
5
Scheme 1.
1
We showed that amide
3
did not result from the could not be detected ( H NMR) in the reaction mixꢀ
classical Beckmann rearrangement because the amide
ture when the reaction was carried out in the absence
of acetylene. Its formation was explained presumably
by the transformation of intermediate 2,3ꢀdiphenylꢀ
Favorskii Institute of Chemistry, Siberian Branch,
Russian Academy of Sciences, ul. Favorskogo 1, Irkutsk,
6
64033 Russia
2Hꢀazirine (6, Scheme 2).
43

44
PETROVA et al.
Ph
O
Ph
–
H
O
Ph
Ph
Ph
Ph
–OH
Ph
H O
2
Ph
3
N
N
N
N
–
O
O
–
6
H
A
Scheme 2.
2
,3ꢀDiphenylꢀ2
form 2,4,5ꢀtriphenylimidazole, along with other 0.07 g (1%) of 2,4,5ꢀtriphenylimidazole (
products [11]. The careful examination of the reaction aqueous layer was acidified with diluted (1 : 3) HCl to
mixture obtained in the synthesis of pyrrole allowed pH ~2–3 and extracted with diethyl ether (3 30 mL).
us to isolate imidazole (yield 1%, Scheme 1), along The ethereal extracts were washed with water and
with other products ; this finding proves the previꢀ dried with Na SO . The ether was removed to give
ously postulated formation of azirine
H
ꢀazirine on heating is known to 0.12 g (1.5%) of 2,3,6ꢀtriphenylpyridine (
4
), and
5
). The
2
×
5
2–4
2
4
6
from ketoxime 1.74 g (55%) of benzoic acid, mp 120–121°C (water),
1
and acetylene in a KOH–DMSO superbasic system [12]: mp 121–125°C. Spectral characteristics are
Scheme 2).
(
identical to those described in literature [13].
The ease of formation of azirine
to result from the enhanced CH acidity of the methylꢀ tals, mp 109–110°C (hexane), [1]: mp 109–110°C.
6
in this case seems
1ꢀVinylꢀ2,3ꢀdiphenylpyrrole (2). Pale yellow crysꢀ
ene group of oxime
tion and the benzene ring: stable carbanion
which is simultaneously of benzylic and
type.
1
located between the oxime funcꢀ
forms,
ꢀcarbonyl
–1
IR (ν, cm ): 3081, 1957, 1888, 1817, 1750, 1641,
A
1
1
602, 1491, 1467, 1412, 1379, 1319, 1300, 1251, 1073,
028, 965, 919, 910, 865, 774, 768, 737, 696, 610.
α
1H NMR (
ꢀPh), 7.34 (m, 1H, Hꢀ
ꢀPh), 7.16 (m, 4H, Hꢀ
ꢀPh), 7.09 (m, 1H, Hꢀ5), 6.69 (dd, 1H, Hꢀ
δ
, ppm,
J
, Hz): 7.35 (m, 2H, Hꢀ
o
,
,
,
,
Thus, the systematic elaboration of the reaction of
ketoxime and its substituted or heterocyclic anaꢀ
2
2
3
3
p, 2ꢀPh), 7.28 (m, 2H, Hꢀ
m
1
o
,
m
, 3ꢀPh), 7.09 (m, 1H, Hꢀ
p
x
logues with acetylene in KOH–DMSO superbasic
systems promises to open a fundamentally new route
3
to 2,3ꢀaryl(hetaryl)ꢀ2Hꢀazirines. These compounds,
JHꢀα, Hꢀx 8.8 Hz, JHꢀβ, Hꢀx 15.7 Hz), 6.50 (d, 1H, Hꢀ4,
if necessary, can be used as intermediates without preꢀ
liminary isolation (similar to the described above synꢀ
3
3
JHꢀ4, Hꢀ5 2.9 Hz), 5.12 (d, 1H, Hꢀ
α
,
JHꢀα, Hꢀx 8.8 Hz),
3
thesis of amide
3).
4
.60 (d, 1H, Hꢀ
β
,
JHꢀβ, Hꢀx 15.7 Hz).
, ppm): 136.0 (Cꢀ
, 2ꢀPh), 131.6 (Cꢀ , 2ꢀPh; Cꢀ ), 130.0 (Cꢀ
13C NMR (CDCl3,
32.0 (Cꢀ
δ
i, 3ꢀPh),
EXPERIMENTAL
1
i
o
α
1
13
15
H, C, and N NMR spectra were recorded on a 2), 128.6 (Cꢀ
m
, 2ꢀPh), 128.2 (Cꢀ , 3ꢀPh), 128.0 (Cꢀ
, 3ꢀPh), 125.6 (Cꢀ , 3ꢀPh), 124.0 (Cꢀ3),
00.61, and 40.55 MHz, respectively) in CDCl soluꢀ 117.0 (Cꢀ5), 110.6 (Cꢀ4), 98.2 (Cꢀ ).
NꢀBenzylbenzamide (3). Mp 105–106°C, [14]: mp
m
Bruker DPXꢀ400 spectrometer (operating at 400.13,
p
, 2ꢀPh; Cꢀ
o
p
1
β
3
tions, using hexamethyldisiloxane as the internal refꢀ
erence. IR spectra were obtained on a Bruker ISFꢀ25 105–107°C. Spectral characteristics are identical to
spectrophotometer as KBr pellets. Mass spectra were those described in literature [14].
recorded on a Shimadzu GCMSꢀQP5050A mass
2
,3,6ꢀTriphenylpyridine (4). White crystals, mp
spectrometer at an ionizing voltage of 70 eV.
9
8–100°C (hexane).
Acetylene was passed at a flow rate of 40–
–1
IR (
521, 1429, 1396, 1369, 835, 762, 745, 694, 629, 581.
1H NMR (
, ppm): 8.15 (m, 2H, Hꢀ , 6ꢀPh), 7.77
s, 2H, Hꢀ4,5), 7.48 (m, 4H, Hꢀ , 2ꢀPh; Hꢀ
, 6ꢀPh), 7.30 (m, 2H, Hꢀ
, 3ꢀPh), 7.25 (m, 1H, Hꢀ
, 2ꢀPh), 7.20 (m, 1H, Hꢀ
, ppm): 156.7 (Cꢀ2), 155.8 (Cꢀ6),
, 3ꢀPh), 140.1 (Cꢀ , 2ꢀPh), 139.4 (Cꢀ4),
, 6ꢀPh), 134.5 (Cꢀ3), 130.3 (Cꢀ , 3ꢀPh),
, 2ꢀPh), 129.0 (Cꢀ , 2ꢀPh; Cꢀ
ν
, cm ): 3055, 3028, 1955, 1894, 1810, 1572,
45 mL/min through a mixture of 5.50 g (0.026 mol) of
1
benzyl phenyl ketoxime (
1) and 1.46 g (0.026 mol) of
δ
o
KOH in DMSO (20 mL) on heating at 130°C for 7 h.
The reaction mixture was cooled, diluted with water
(
o
m, 6ꢀPh),
7
7
7
.41 (m, 1H, Hꢀ
.28 (m, 2H, Hꢀ
.24 (m, 2H, Hꢀ
13C NMR (
p
o, 3ꢀPh),
(
60 mL), and extracted with diethyl ether (5 30 mL).
×
m
p, 3ꢀPh),
The ethereal extracts were washed with water and
dried with potassium carbonate. After removal of the
ether, the residue was fractionated on an Al O column
m
p, 2ꢀPh).
2
3
δ
(
5
eluent used was hexane, then hexane–diethyl ether, 140.5 (Cꢀ
: 1) to give 1.08 g (17%) of 1ꢀvinylꢀ2,3ꢀdiphenylpyrꢀ 139.2 (Cꢀ
role ( ), 0.65 g (12%) of ꢀbenzylbenzamide ( ), 129.7 (Cꢀ
i
i
i
o
2
N
3
o
p
p, 6ꢀPh),
DOKLADY CHEMISTRY Vol. 436
Part 2
2011

2,4,5ꢀTRIPHENYLIMIDAZOLE
45
1
3
28.8 (Cꢀ
ꢀPh), 127.1 (Cꢀ
m
, 6ꢀPh), 128.4 (Cꢀ
m
, 2ꢀPh), 127.9 (Cꢀ
m
,
p
,
2. The Chemistry of Hydroxylamines, Oximes and Hydroxꢀ
amic Acids, Rappoport, Z. and Liebman, J. F., Eds.,
Chichester: Wiley, 2008, p. 241.
o, 6ꢀPh), 118.6 (Cꢀ5).
15N NMR (
MS (
δ
, ppm): –70.9.
3
4
5
6
7
. Wang, Z., Comprehensive Organic Name Reactions and
Reagents, London: Wiley, 2009, Pt 3, p. 2793.
. Schmidt, E.Yu., Mikhaleva, A.I., Vasil’tsov, A.M.,
et al., Arkivoc, 2005, vol. vii, pp. 11–17.
. Mikhaleva, A.I., Shmidt, E.Yu., Ivanov, A.V., et al., Zh.
Org. Khim., 2007, vol. 43, no. 2, pp. 236–238.
. Vasil’tsov, A.M., Zaitsev, A.B., Schmidt, E.Yu., et al.,
+
·
m
/z
): 307 [M] .
For C H N anal. calcd. (%): C, 89.87; H, 5.57;
2
3
17
N, 4.56.
M
307.
Found (%): C, 89.79; H, 5.65; N, 4.48.
,4,5ꢀTriphenylimidazole (5). White crystals, mp
74°C (ethanol), [15]: mp 271–272°C. Spectral charꢀ
acteristics are identical to those described in literature
2
Mendeleev Commun., 2001, vol. 11, pp. 74–75.
2
. Trofimov, B.A., Schmidt, E.Yu., Mikhaleva, A.I.,
Zorina, N.V., et al., Mendeleev Commun., 2007, vol. 17,
pp. 40–42.
[
15].
+
·
MS (m/z): 296 [M] .
8. Trofimov, B.A., Schmidt, E.Yu., Mikhaleva, A.I., et al.,
Tetrahedron Lett., 2009, vol. 50, pp. 3314–3317.
. Petrova, O.V., Ushakov, I.A., Sobenina, L.N., et al., Zh.
Org. Khim., 2010, vol. 46, no. 9, pp. 1412–1413.
For C H N anal. calcd. (%): C, 85.11; H, 5.44;
21
16
2
9
N, 9.45.
M
296.
Found (%): C, 85.21; H, 5.43; N, 9.34.
1
1
1
1
0. Petrova, O.V., Ushakov, I.A., Sobenina, L.N., et al.,
Khim. Geterotsikl. Soedin., 2010, no. 6, pp. 938–940.
1. Bowie, J.H. and Nussey, B., J. Chem. Soc., Perkin
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2. Aldrich Catalog Handbook of Fine Chemicals 2009–
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3. The Sadtler Standard Spectra: NMR Chemical Shift
Index, Philadelphia: Sadtler Res. Lab., 1972, vol. 1,
no. 57, p. 3.
ACKNOWLEDGMENTS
This work was supported by the Council for Grants
of the President of the Russian Federation for Support
of Leading Scientific Schools (grant no. NShꢀ3230ꢀ
2
010.3).
1
4. Perreux, L., Loupy, A., and Volatron, F., Tetrahedron
,
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ꢀ
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DOKLADY CHEMISTRY Vol. 436
Part 2
2011