Aniline alkylation with Di- and tribromopropane

Full text of DOI:10.1134/S1070428009080247

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2009, Vol. 45, No. 8, pp. 1250−1251. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © V.M. Ismailov, I.A. Mamedov, N.N. Yusubov, 2009, published in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 8, pp. 1258−
1259.
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Aniline Alkylation with Di- and Tribromopropane
V. M. Ismailov, I. A. Mamedov, and N. N. Yusubov
Baku State University, Baku, ?Z-1148 Azerbaijan
e-mail: niftali-yusubov@rambler.ru
Received May 20, 2008
DOI: 10.1134/S1070428009080247
We formerly performed a condensation of aniline with
1,2-dibromoethane [1] that yielded compounds with a
linear (1,2-dianilinoethane) and cyclic (N,N-diphenyl-1,4-
diazine) structures. In extension of this study we
investigated the aniline alkylation with di- and
tribromopropane.
2-Methylene-1-phenylazirane (VII) may form by two
routes: either compound VI undergoes the intramolecular
N-alkylation to give compound VII, or the product of the
primary alkylation, 2,3-dibromopropylaniline A, suffers the
intramolecular alkylation at the nitrogen atom forming an
aziridine ring with subsequent dehydrobromination.
PhNH2 + CH2BrCH2CH2Br
PhNH2 + CH2BrCHBrCH2Br
I
II
I
V
CH2
CH2
CH2
PhNHCH2CH2CH2Br + PhN
C
H2
CH2
CH_CH2Br
III
CHBr
Ph NH
Ph
N
_HBr
_HBr
IV
CH2Br
Ph
A
At excess K2CO3 in DMSO environment the
condensation of aniline (I) with 1,3-dibromopropane (II)
at heating (60–80°C) led to the formation of N-(3-
bromopropyl)-aniline (III) and N-phenylazetidine (IV).
At higher temperature the fraction of the cyclic product
increased.
CH2
N
_HBr
CH2
C
VII
1
In the H NMR spectrum of compound VII the
resonance signals at δ, ppm, 7.5 m (5H), 5.1 m (2H),
and 2.0 m (2H) should be assigned respectively to the
protons of phenyl, vinyl, and methylene moieties.
The structure of compounds III and IV was confirmed
1
by H NMR spectra.
Under similar conditions the aniline alkylation with
1,2,3-tribromopropane (V) also proceeded as N-alkylation
and gave N-(2-bromoallyl)aniline (VI) and 2-methylene-
1-phenylazirane (VII).
Reaction of aniline with 1,3-dibromopropane. To
a mixture of 0.13 mol of compound I and 0.25 mol of
K2CO3 in 75 ml of DMSO was added dropwise within 1
h at stirring 0.13 mol of 1,3-dibromopropane at room
temperature. While adding the reagent the mixture turned
light-brown. Then the mixture was heated for 7 h at 60°C,
cooled, diluted with water, and extracted with ether. The
formed crystals of compound IV were filtered off. From
the filtrate on removing the ether we obtained compound
III as viscous fluid of dark-brown color.
PhNH2 + CH2BrCHBrCH2Br
I
V
K2CO3 DMSO
,
PhNHCH2CBr CH2
_2HBr
VI
The formation of compound VI may be regarded as
the N-alkylation of aniline with tribromopropane (V) with
the simultaneous dehydrobromination.
N-(3-Bromopropyl)aniline (III). Yield 31 g (48%),
bp 121°C (0.3 mm Hg), d420 1.3432, nd20 1.4827. 1H NMR
1250

ANILINE ALKYLATION WITH DI- AND TRIBROMOPROPANE
1251
spectrum, δ, ppm: 1.25 m (2H, CCH2C), 3.3 t (2H, CH2Br),
3.9 m (2H, NCH2 ), 4.2 br.s (1H, NH), 6.9 m (5H, C6H5).
Found, %: C 50.41; H 5.87; Br 37.48; N 6.48. C9H12BrN.
Calculated, %: C 50.46; H 5.40; Br 37.38; N 6.54.
N-(2-Bromoallyl)aniline (VI). Yield 7 g (26%), bp
110°C (0.5 mm Hg), d420 1.4226. 1H NMR spectrum, δ,
ppm: 3.68 d (2H, NCH2), 5.5 d (2H, =CH2), 6.25–7.1 m
(5H, C6H5). Found, %: C 50.6; H 4.7; Br 37.7; N 6.6.
C9H10BrN. Calculated, %: C 50.9; H 4.7; Br 37.9; N 6.6.
N-Phenylazetidine (IV). Yield 22 g (49%), mp 212°C.
1H NMR spectrum, δ, ppm: 1.2 m (2H, CH2), 2.65 m
(4H, 2CH2), 7.1 m (5H, C6H5). Found, %: C 81.27; H 8.32;
N 10.47. C9H11N. Calculated,%: C 81.20; H 8.27; N 10.52.
2-Methylene-1-phenylazirane (VII). Violet crystals,
recrystallized from 2-propanol. Yield 3.4 g (22%), mp
208°C. Found, %: C 82.7; H 7.0; N 10.4. C9H9N. Calculat-
ed, %: C 82.4; H 6.9; N 10.7.
1H NMR spectra were registered on a spectrometer
Varian T-60, solvent CCl4, internal reference HMDS.
Reaction of aniline with 1,2,3-tribromopropane.
To a mixture of 0.13 mol of aniline and 0.25 mol of K2CO3
in DMSO was added dropwise 0.13 mol of 1,2,3-tri-
bromopropane. The reaction mixture was stirred for 1.5 h
at 20°C and 7–8 h at 110°C, it was cooled, diluted with
water, and extracted with ether. The formed violet crystals
of compound VII were filtered off, and compound VI
was obtained from the ether extract.
REFERENCES
1. Ismailov V.M., Mamedov I.A., and Yusubov N.N., Zh. Org.
Khim., 2004, vol. 40, p. 312.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 8 2009