Formation of N-benzylbenzamide from benzyl phenyl ketone oxime in a system C2H2-KOH-DMSO. Key role of acetylene

Full text of DOI:10.1134/S1070428010090265

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 9, pp. 1416−1417. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © O.V. Petrova, I.A. Ushakov, L.N. Sobenina, A.I. Mikhaleva, B.A. Trofimov, 2010, published in Zhurnal Organicheskoi Khimii, 2010,
Vol. 46, No. 9, pp. 1412−1413.
SHORT
COMMUNICATIONS
Dedicated to Full Member of the Russian Academy of Sciences
th
N.S. Zefirov on occasion of his 75 anniversary
Formation of N-Benzylbenzamide
from Benzyl Phenyl Ketone Oxime in a System
C H –KOH–DMSO. Key Role of Acetylene
2
2
O. V. Petrova, I. A. Ushakov, L. N. Sobenina, A. I. Mikhaleva, and B. A. Trofimov
Faworsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
Irkutsk, 664033 Russia
e-mail: boris_trofimov@irioch.irk.r
Received April 14, 2010
DOI: 10.1134/S1070428010090265
Oximes rearrange into amides under the action of alongside the expected pyrrole II (yield 14–34%) N-ben-
strong acids (Beckmann rearrangement) [1]. Only seldom zylbenzamide (III) was obtained (14–24%) (Scheme1).
this rearrangement occurs in the presence of bases, for
instance, that of benzoquinosylidone E- and Z-oximes [2].
The preparation of benzamide from benzaldoxime in the
system KOH–DMSO was described through hydration
of the intermediate nitrile [3].
Besides after acidifying the reaction mixture benzoic
acid was isolated (up to 56%).
Special experiment showed that amide III was not
a product of oxime I rearrangement under the action of
KOH–DMSO (at heating oxime I under the same condi-
tions without acetylene it was nearly completely recov-
ered, to 95–97%). Obviously the key role in the formation
of amide III from oxime I belonged to acetylene.
In the course of the synthesis of 1-vinyl-2,3-diphe-
nylpyrrole (II) from benzyl phenyl ketone oxime (I)
and acetylene by Trofimov reaction [4–6] in the system
KOH–DMSO at the atmospheric pressure (130°C, 7 h)
Apparently O-vinyloxime IV, the intermediate in the
synthesis of pyrroles from oximes and acetylene, was
deprotonated by the superbase KOH–DMSO forming
carbanion V that further replaced intramolecularly the
vinyloxy anion with the closure of the azirine ring VI
Scheme 1.
(Scheme 2). Its hydration into hydroxyaziridine VII fol-
lowed by a rearrangement resulted in amide III.
The stage of azirine formation from O-vinyloxime
under the action of the superbase was suggested recently
for the understanding of the assembling of 4-methylene-3-
oxa-1-azabicyclo[3.1.0]hexanes from ketoximes, ketones,
and acetylene [7]. In essence this stage resembles the
azirine synthesis from oximes or their ethers by Hoch–
Campbell reaction [1, 8].
This reaction fundamentally supplements the common
1
416

FORMATION OF N-BENZYLBENZAMIDE
1417
Scheme 2.
similar to those published in [10].
The water layer was acidified with diluted (1 : 3)
HCl till pH ~2–3 and extracted with ether (3 × 30 ml),
the combined extracts were thrice washed with water
Ph
O
Ph
_
Ph
OH
Ph
(
3 × 20 ml), dried with Na SO . On removing ether we
2 4
N
N
V
obtained 1.79 g (56%) of benzoic acid as fine white crys-
tals, mp 120–121°C (from water) (mp 121–125°C [11]).
O
1
13
H and C NMR spectra were registered on a spec-
trometer Bruker DPX 400 [operating frequencies 400.13
IV
1
13
_
( H) and 100.6 ( C) MHz], solvent CDCl , internal refer-
3
Ph
Ph
O
ence HMDS. IR spectra were recorded on a spectropho-
tometer Bruker IFS-25 from pellets with KBr.
N
The study was carried out under the financial support
of the program of the President of the Russian Federation
for the support of the leading scientific schools (grant
NSh 3230-2010.3).
VI
Ph
H
O
H O
Ph
2
REFERENCES
III
N
1. Mikhaleva, A.I., Zaitsev, A.B., and Trofimov, B.A., Usp.
Khim., 2006, vol. 75, p. 884.
H
2
3
4
5
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p. 2189.
VII
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(N-Vinylpyrroles). Novosibirsk: Nauka, 1984.
N-Benzylbenzamide (III). A mixture of 5.50 g
26 mmol) of oxime I and 1.45 g (26 mmol) of KOH
. Bellina, F. and Rossi, R., Tetrahedron, 2006, vol. 62,
p. 7213.
(
in 20 ml of DMSO was stirred at 130°C, and acetylene
was passed through for 7 h at a rate 40–45 ml/min.
On cooling to room temperature 15 ml of DMSO was
distilled off at a reduced pressure. The residue was
diluted with water (40 ml) and extracted with ether
. The Chemistry of Hydroxylamines Oximes and Hydroxamic
Acids, Rappoport, Z., and Liebman, J.F., Eds., Wiley:
Chichester, 2008, p. 241.
6
. Wang, Z., Comprehensive Organic Name Reactions and
Reagents, pt. 3, London: Wiley, 2009, p. 2793.
(
6 × 30 ml), the combined extracts were thrice washed
7
. Trofimov, B.A., Schmidt, E.Yu., Mikhaleva, A.I., Usha-
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Aleksandrov, G.G., and Dyachenko, O.A., Tetrahedron
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with water (30 ml) and dried with potassium carbon-
ate. On removing the solvent the red-brown transparent
oily substance (3.83 g) was subjected to column chro-
matography on aluminum oxide (eluent first hexane,
then a mixture hexane–dichloromethane, 10 : 1). We
obtained 0.902 g (14%) of 1-vinyl-2,3-diphenylpyrrole
8. Name reactions in Heterocyclic Chemistry Li, J.J., Ed.,
New Jersey: John Wiley & Sons Inc., 2004, p. 22.
9. Aldrich., 2007–2008, p. 291.
(
(
(
II), mp 109–110°C (mp 109–110°C [3]), and 1.314 g
24%) of N-benzylbenzamide (III), mp 105–106°C
mp 104–106°C [9]). IR, H and C NMR spectra were
1
0. Davidsen, S.K., May, P.D., and Summers, J.B., J. Org.
Chem., 1991, vol. 56, p. 5482.
1
13
11. Beilst. H.9.92.
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