Synthesis of N-and C-trimethylsilyl-substituded anililes

Article abstract of DOI:10.1134/S1070363208050095

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl) bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6- trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.

Full text of DOI:10.1134/S1070363208050095

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 5, pp. 892–897. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © P.A. Storozhenko, Z.V. Belyakova, O.A. Starikova, V.M. Nosova, T.I. Shulyat’eva, A.S. Frenkel’, M.V. Pecherskii, 2008, published
in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 5, pp. 750–755.
Synthesis of N- and C-Trimethylsilyl-Substituded Anililes
P. A. Storozhenko, Z. V. Belyakova, O. A. Starikova, V. M. Nosova,
T. I. Shulyat’eva, A. S. Frenkel’, and M. V. Pecherskii
State Research Institute of Chemistry and Technology of Organoelemental Compounds
sh. Entuziastov Highway 38, Moscow, 111123 Russia
fax: 007(495)913-25-38
e-mail: eos2004@inbox.ru
Received September 21, 2007
Abstract—N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with
trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of
substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a
trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline,
2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylani-
line, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline,
2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The
1
structures of the compounds obtained were established by the chromato-mass spectrometry and H, 13C, and
29Si NMR spectroscopy.
DOI: 10.1134/S1070363208050095
Development of new polymeric materials with
desired physicomechanical characteristics is an im-
portant problem nowadays. It is solved in particular by
preparing new grades of polyolefines. Recently the
interest has grown to imine complexes of the transition
metals, the components of postmetallocene catalysts
of olefins polymerization exhibiting high activity and
selectivity. Introduction of substituents containing
heteroatoms like silicon in the structure of ligand may
increase the thermostability of the catalytic system
what is extremely feasible in the olefins polymeriza-
tion. The catalytic systems with the silicon-containing
imine complexes virtually are not documented. o-C-
Silyl-substituted anilines are required for preparation
of these complexes. The latter can be obtained from N-
silyl-substituted anilines. Scanty information exists on
both these substances.
silyl-N,N-bis(trimethylsilyl)aniline was formed in up
to 53% yield in reaction of 2-bromo(chloro)-N,N-bis
(trimethylsilyl)anilines with lithium [3].
The aim of our work was the synthesis of C-silyl-
substituted anilines. For developing suitable procedure
we have studied the silylation of bromoanilines. First
we studied the formation of N-silyl-substituted anilines
by the reaction (1).
R2
R2
1. EtMgBr
2. Me3SiCl
(1)
R1
Br
R1
Br
R3NSiMe3
NH2
Ia−Ic
IIa−IIf
I, R1 = R2 = H (a), R1 = Br, R2 = H (b), R1 = R2 = Br (c);
II, R1 = R2 = H, R3 = SiMe3 (a), R1 = Br, R2 = H, R3 =
SiMe3 (b), R1 = Br, R2 = R3 = H (c), R1 = R2 = Br, R3 = H
(d), R1 = R2 = Br, R3 = SiMe3 (e), R1 = R2 = H; R3 = SiMe3 (f).
N-Trimethyl(triethyl)silyl-substituted anilines are
formed by the reaction of aniline with trimethyl- and
triethylclorosilanes in 56–80% yield [1, 2]. 2-Bromo
(chloro)-N,N-bis(trimethylsilyl)-substituted
anilines
are prepared in 43% and 68% yield respectively from
the corresponding halogen-containing anilines by
treating them with ethylmagnesium bromide, and sub-
sequently, with trimethylchlorosilane [3]. 2-Trimethyl-
2-Bromo-N,N-bis(trimethylsilyl)aniline IIa was
prepared from 2-bromoaniline Ia in 40% yield. The
attempt to prepare 2,6-dibromo-N,N-bis (trimethyl-
892

SYNTHESIS OF N- AND C-TRIMETHYLSILYL-SUBSTITUDED ANILILES
893
silyl)aniline IIb from 2,6-dibromoamiline Ib failed.
We have isolated 2,6-dibromo-N-trimethyl-silylaniline
IIc and only traces of compound IIb. The twice
prolonged reaction gave insignificant effect, the yield
of the compound IIb was no more than 6.8%. We have
studied the possibility of formation of the compound
IIb by disproportionation (2) of compound IIc. The
yield was negligible. For instance, after boiling of 97%
compound IIc. For 7 h the reaction mixture contained
20% of dibromoaniline Ib, 68% of monosilyl-sub-
stituted compound IIc and only 5% of the disubstituted
substance IIb.
compound IVb. It formed evidently by N-metallation
of compound IIa with butyllithium followed by the
reaction with trimethylchlorosilane and incomplete
removal of the silyl protective group.
2,4,6-Tribromoaniline Ic gave 2,4,6-tribromo-N-
trimethylsilylaniline IId in 40.9% yield, and the yield
of 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline IIe
was not higher than 6.6% similar to the synthesis of
compound IIb.
C-Silyl-substituted anilines were prepared by re-
action (3). The process included metallation of N-
silyl-substituted anilines IIa, IIb, IIe, and IIf with
butyllithium, treating the product obtained with
trimethylchlorosilane, and removing protective group
with methanol or dilute hydrochloric acid.
IIc → Ib + IIb + IIc.
(2)
Compound IIb was isolated in pure state by
distillation of the bottoms from several syntheses of
R2
R2
R2
1. BuLi
2. Me3SiCl
HCl
II
+
(3)
R1
Me3Si
R1
Me3Si
R1
Me3Si
NHSiMe3
N(SiMe3)2
NH2
IIIа–IIId
IVа–IVd
Vа–Vd
III, R1 = R2 = H, R3 = R4 = SiMe3 (a), R1 = Br, R2 = H, R3 = R4 = SiMe3 (b), R1 = Br, R2 = R3 = R4 = SiMe3 (c), R1 = R2 =
Br (d); IV, R1 = R2 = H (a), R1 = Br, R2 =H (b), R1 = SiMe3, R2 = H (c), R1 = SiMe3; R2 = Br (d); V, R1 = Br, R2 = H (a), R1 =
Br, R2 = SiMe3 (b), R1 = R2 = Br (c), R1 = SiMe3, R2 = Br (d).
2-Trimethylsilylaniline IVa was prepared starting aniline IVc, 2-bromoaniline Ia, and 2-bromo-6-tri-
with compound IIa. We failed to isolate intermediate
2-trimethylsilyl-N,N-bis(trimethylsilyl)aniline IIIa.
methylsilyl-N-trimethylsilylaniline Va were found in
the reaction mixture. At larger amount of butyllithium
it reacted with trimethylchlorosilane according to
equation (4). By the distillation of the reaction mixture
in such cases the butyltrimethylsilane was isolated and
identified by 1H, 13C, and 29Si NMR spectra.
The vacuum distillation of compound IIb occurred
with decomposition. Therefore we tried to use directly
the crude product in the reaction with butyllithium. It
turned out that the composition of the reaction products
depends on the reagents ratio. At the ratio compound
Ib : butyllithium 1 : 2.5 and 1 : 4 the main reaction
product was 2-bromo-6-trimethylsilylaniline IVb, and
its yield reached 65%. 2-Bromo-6-trimethylsilyl-N,N-
bis(trimethylsilyl)aniline IIIb, 2,6-bis(trimethylsilyl)
BuLi + Me3SiCl → Me3SiBu.
(4)
Reaction of compound IIc with butyllithium gave
2,5-dibutyl-N,N-dibutylaniline VI, N-butyl-N-trime-
thylsilylaniline VII, 2-trimethylsilyl-N,N-dibutylani-
line VIII, and 4-bromo-N,N-dibutylaniline IX.
Br
1. BuLi
2. Me3SiCl
(5)
IIc
+
+
+
Bu
Bu
SiMe3
NBu2
NBuSiMe3
VII
NBu2
VIII
NBu2
IX
VI
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 5 2008

894
STOROZHENKO et al.
The formation of compounds VII–IX originated
Xa and 2-bromo-4-trimethylsilyl-N-trimethylsilylani-
line Xb.
from the elimination of one or two bromine atoms.
Compound IX results from the migration of the second
bromine atom from the position 2 to the position 4
with respect to amino group. The rearrangements of
this type were described in [4].
R2
Br
R1
Br
R3NSiMe3
Xа–Xb
(6)
R1 = Br, R2 = R3 = SiMe3 (a); R1 = R3 = H; R2 = SiMe3 (b).
Bu
NBu2
NBu2
Treating with butyllithium the reaction mixture
prepared from compound Ic and trimethylchlorosilane
resulted in formation of 2,4-dibromo-N,N-bis(trime-
thylsilyl)aniline IIf, 4-bromo-2,6-bis(trimethylsilyl)
aniline IVd, 2,4-dibromo-6-trimethylsilyl-N-trimethyl-
silylaniline Vb, 2,4-dibromo-6-trimethylsilyl-N,N-bis
(trimethylsilyl)aniline IIId, 4-bromo-2,6-bis (trime-
thylsilyl)-N-trimethylsilylaniline Vc, 2,4-dibromo-6-
trimethylsilyl-N-trimethylsilylaniline Vd, and of com-
pounds of the general formula X, namely, 2,6-
dibromo-4-trimethylsilyl-N,N-bis(trimethylsilyl)aniline
Trimethylsilyl group can replace either one or two
bromine atoms in ortho- and para-position, but
substitution of three bromine atoms was not observed.
The variety of compounds obtained is presumably due
to rearrangements occurring in the reaction mixture.
The structures of the compounds obtained were
established by chromato-mass spectrometry (Table 1)
and 1H, 13C, and 29Si NMR spectroscopy (Table 2).
The starting bromo- and dibromoanilines are
sufficiently stable to the electron impact, and in their
Table 1. Mass spectra of substituted anilines
Comp. no.
m/z (Jrel, %)
171 (М – 1, 100), 92 (36.5),65(38.5)
251 (М+, 100), 170 (5.8), 90 (21.2)
Iа
Ib
317 (М+, 1.1), 302 (9.6), 286(0.1), 271(), 256 (100), 229 (15.4), 214 (23.1), 148 (9.6), 137 (5.8), 73 (7.7)
395 (М+, 3.8), 380 (100), 301 (21.2), 286 (13.5), 137 (9.6), 73 (26.9)
IIа
IIb
IIc
323 (М+, 34.6), 308 (100), 229 (38.5), 214 (7.7), 148 (19.2), 137 (13.5), 73 (17.3)
395 (М+, 2.8), 380 (71.7), 323 (51.9), 308 (100), 292 (14.2), 226 (16.0), 146 (16.9), 73 (64.2)
389 (М+, 1.9), 374 (51.9) 286 (46.2), 220 (100), 73 (44.2)
461 (М+, 1.9), 446 (26.9) 358 (32.7), 292 (100), 204 (11.5), 137 (3.8), 73 (67.3)
467 (М+, 3.8), 452 (73.1), 364 (100), 300 (51.9 ), 139 (13.5), 73 (88.5)
237 (М+, 1.9), 222 (9.6), 165 (48.1), 159 (100), 133 (48.1), 74 (13.5)
317 (М+, 40.4), 302 (65.4), 286 (7.6), 220 (7.6), 148 (78.8), 137 (7.6), 73 (100)
317 (М+, 7.6), 302 (100), 286 (0.5), 221 (36.5), 148 (17.3), 137 (9.6), 73 (36.5)
389 (М+, 7.6) 374 (100), 317 (7.8), 302 (23.1), 286 (34.6), 220 (44.2), 137 (9.6), 73 (80.8)
389 (М+, 16.0), 374 (10.4), 317 (5.7), 300 (5.7), 286 (42.5), 220 (72.6), 73 (100)
395 (М+, 26.9), 380 (36.5), 226 (9.6), 146 (13.5), 73 (100)
IIf
IIIb
IIIc
IIId
IVc
IVd
Va
Vb
Vc
Vd
VI
315 (М+ – 2, 0.1), 215 (96.2), 159 (100), 103 (11.5), 61 (13.5)
277 (М+, 1.9), 231 (46.2), 175 (100), 119 (98.1), 105 (17.3), 73 (17.3)
219 (М+ – 2, 1.9), 187 (88.5), 131 (100), 103 (19.2), 75 (21.5)
395 (М+, 7.5), 380 (100), 301 (31.1), 286 (14.1),220 (4.7),139 (12.3), 73 (49.1)
317 (М+, 66.0), 302 (66.1), 286 (3.6), 221 (100), 206 (73), 148 (42.3), 137 (9.6), 73 (38.5)
VII
VIII
IXa
IXb
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 5 2008

SYNTHESIS OF N- AND C-TRIMETHYLSILYL-SUBSTITUDED ANILILES
895
mass spectra molecular ion peak has the greatest
intensity. Main fragment ions are formed by elimina-
tion of bromine. Intensities of peaks of the molecular
ions in the mass spectra of compounds obtained vary
in a broad range, 0.1–66%.
based on the analysis of spectra of pure compounds
and their mixtures considering the multiplicity and the
integral intensity of proton signals in 1H NMR spectra,
and the chemical shifts of signals and their relative
intensity in 13C(APT) and 29Si NMR spectra. The two-
dimentional COSY, HSQC, and HMBC procedures
Mass spectra of C-silyl-substituted anilines contain
up to 100% of ion with m/z 73 corresponding to
trimethylsilyl group. Such decay is not characteristic of
N-substituted anilines. More often elimination of the
methyl group occurs. The bromine atom having o-loca-
tion with respect to trimethylsilyl group forms a
species [Me2SiBr]+ with m/z 137–139 units. Among
the other pathways of fragmentation note the
elimination of 96 (Br + Me), 169 (Me3Si + Br + Me),
109 (Br + 2Me), 103 (Me3Si + 2Me), and 155 (Me3Si +
Br) mass units.
1
were used including 2D-correlations H–29Si for the
attribution of signals of SiMe3 groups. Note that at the
successive substitution of protons in the NH2 group of
2,6-dibromoaniline Ib with trimethylsilyl groups
(products IIb and IIc) the chemical shift of the
quarternary carbon atom C2–Br was the most strongly
affected (108.82, 116.36, and 127.82 ppm).
EXPERIMENTAL
1
13
Attribution of signals in the H, C, and 29Si NMR
2-Bromoaniline, 2,6-dibromoaniline, and 2,4,6-
tribromoaniline were prepared according to [5].
spectra presented in Table 2 and in Eperimental is
Table 2. 1H, 13C, and 29Si(XC) chemical shifts (CDCl3, 27°C).
1Н, δ, ppm, number of atoms
The number of atom in aniline
Comp. no.
NH, NH2
N–SiMe3
С–SiMe3
3
4
5
6
7.40 d
1Н
6.62 t
1Н
7.10 t
1Н
6.75 d
4.1 br
2H
Ia
1Н
7.36 d
1Н
6.48 t
1Н
7.36 d
1Н
4.56
2H
Ib
7.57 d
1Н
6.93 t
1Н
7.17 t
1Н
7.02 d
0.128 s
18Н
IIa
IIb
IIc
IId
IIe
IIIb
IVaа
IVb
Va
IXc
1Н
7.54 d
1Н
6.75 t
1Н
7.54 d
1Н
0.2 s
18Н
7.43 d
1Н
6.56 t
1Н
7.43 d
1Н
3.6
1H
0.35 s
9Н
7.56 s
1Н
7.56 s
1Н
3.75
1H
0.30 s
9Н
7.66 s
1Н
7.66 s
1Н
0.17 s
18Н
7.58 d
1Н
6.91 t
1Н
7.43 d
1Н
0.19 s
18Н
0.35 s
9Н
7.19 t
1Н
6.79 t
1Н
7.32 d
1Н
3.72 br
2H
0.36
9H
7.45 d
1Н
6.63 t
1Н
7.24 d
1Н
4.3
0.37 s
9Н
2H
7.50 d
1Н
6.73 t
1Н
7.27 d
1Н
3.5
0.34 s
0.35 s
9Н
1H
9Н
6.52 m
2Н
6.48 m
2Н
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 5 2008

896
STOROZHENKO et al.
Table 2. (Contd.)
13С, δ, ppm
13Si, δ, ppm
The number of atom in aniline
Comp. no.
N–SiMe3 С–SiMe3 N–SiMe3
С–SiMe3
1(C–N)
2(C–Br)
quart.
3
4
5
6
quart.
144.04
141.96
147.16
147.30
144.29
109.28
108.82
126.84
127.82
116.36
132.55
131.71
132.98
132.21
132.25
119.35
119.34
125.14
125.62
121.58
128.28
131.70
127.56
132.21
132.25
115.70
108.82
131.81
127.82
116.36
Ia
Ib
1.88
2.56
1.82
6.17
IIa
IIb
IIc
IId
IIe
IIIb
7.78
8.58
151.22
151.31
147.92
127.89
115.28b
110.56
134.69
134.08
124.81
118.31
119.15
134.86
133.79
143.29
C–Si
3.22
2.25
–0.79
–0.89
5.85
–3.10
–5.59
–4.41
IVаа
122.62
C–Si
124.40
C–Si
IVb
Vа
IXc
158.73
quart.
142.53
quart.
a
For the convenience of comparison the numbering of carbon atoms in compound IVa differs from the standard one: C6 is the quarternary
carbon atom adjacent to SiMe3. Chemical shift of the proton H2 6.64 ppm (doublet, 1H); the signals of CH-carbon atoms C3 and C5
(134.98 and 130.48) are not attributed. b CH-carbon atom. c The multiplets H2,6 and H3,5 of the AA'BB' spin system of protons in aniline
(6.52 and 6.48 ppm) are not attributed. The signals of CH-carbon atoms in aniline C2,6 and C3,5 (130.40 and 120.46 ppm) are not
attributed. The signals of the quarternary carbon atoms in aniline C1 and C4 (142.53 and 158.73 ppm) are not attributed. The signals of
protons of n-Bu group, δ, ppm: 0.94 (6H, Me), 1.39 (4H, CH2), 1.55 (4H, CH2), 2.55 (4H, NCH2). The signals of carbon atoms of n-Bu
group, δC, ppm: 13.89 (Me), 22.92 (CH2), 32.21 (CH2), 34.16 (NCH2).
GLC analysis was carried out on a Tsvet-500
spectrometer, operating frequencies 600 MHz (1H),
150.9 MHz (carbon atoms), 119.2 MHz (silicon atoms)
respectively.
chromatograph, 2000 × 3 mm column, stationary phase
15% of PMS-2000 on Chromaton N-AW-DMCS,
particle size 0.250–0.315 mm, temperature of the
vaporizer and the detector 280°C, the detector current
100 mA, ramp from 50°C to 280°C at a rate 12 deg min–1,
carrier gas helium, flow rate 50 ml min–1.
2-Bromo-N,N'-bis(trimethylsilyl)aniline (IIa). A
solution of 10.3 g of 2-bromoaniline in 60 ml of ether
was treated with a solution of ethylmagnesium bro-
mide prepared from 3.5 g of magnesium and 11.2 ml
of ethyl bromide in 50 ml of ether. The mixture
obtained was refluxed for 4 h, and 18.3 ml of trime-
thylchlorosilane was added to the reaction mixture in
the course of 0.5 h. After that the resulting mixture was
refluxed for 8 h and the precipitate was filtered off
under nitrogen. Ether was distilled from the filtrate,
and the residue was distilled in a vacuum to give 7.6 g
(40%) of the compound IIa, bp 130–135°C, nD20
1.5185.
Mass spectra were obtained on a Hewlett–Packard
HP-5971A mass spectrometer at the ionizing voltage
70 V. For the separation of compounds a quartz
25000x0.32 mm capillary column was used, the
stationary phase the DB-5 methylphenylsiloxane
elastomer, thickness of the film 25 nm. Analyses were
carried out at ramp from 50 to 280°C at a rate
7 deg min–1, carrier gas helium.
1H, 13C, and 29Si NMR spectra were taken from
solutions in CDCl3 on a Bruker AVANCE-600
2,6-Dibromo-N-trimethylsilylaniline (IIc). This
compound was prepared analogously from 15.3 g of
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SYNTHESIS OF N- AND C-TRIMETHYLSILYL-SUBSTITUDED ANILILES
897
2,6-dibromoaniline and the above-mentioned amounts
of other reagents to give 10.5 g (53.3%) of compound
IIc with the main substance content 97.6%, bp 101–
102°C (2 mm Hg), nD20 1.5720, and 0.9 g of the fraction
with bp 120–130°C (2 mm Hg), n2D0 1.591
characterized as a mixture of 5% of compound Ib, of
43% of compound IIc and 47% of compound IIb.
dried over zeolites, ether was removed, and the residue
was distilled in a vacuum to give 4.8 g (67.9%) of
compound IVb, bp 145–150°C (4 mm Hg), nD20 1.5615.
The reaction mixture contained also the products
IIIb and Va.
The vacuum distillation of a mixture obtained by
trimethylsilylation of 0.029 mol of dibromoaniline in
30 ml of ether and treated with a butyllithium solution
under the above-described conditions but at 1:4
dibromoaniline/butyllithium molar ratio provided 4.6 g
(65%) of compound IVb with the main substance
content 98%, bp 135–140°C (5 mm Hg), nD20 1.5615.
Besides, 4.7 g of the volatile products were collected
in the trap. Repeated distillation of the latter gave 3.8 g
of butyltrimethylsilane, bp 93–94°C, n2D0 1.4030.
Disproportionation of compound (IIc). Com-
pound IIc with the main substance content 97% was
heated at 50–60°C. After 12 h of heating the reaction
mixture contained 12.2% of dibromoaniline, 78.8% of
the starting compound, and 3.2% of compound IIb.
After additional 7 h the reaction mixture contained
20% of dibromoaniline, 68% of the starting compound,
and 5% of compound IIb.
2,4,6-Tribromo-N-trimethylsilylaniline (IId) was
prepared analogously to IIa from 0.045 mol of com-
pound Ic and the above-mentioned amounts of other
reagents. Distillation of the reaction mixture gave 8.8 g
of a substance of bp 110–120°C (2.5 mm Hg), nD20
1.5755, consisting to 84% of the product IId (yield
40.9%) and to 16% of the compound IIe.
1H NMR spectrum (CDCl3), δ, ppm: -0.05 s (9H,
SiMe3), 0.47 m (2H, CH2Si), 1.30 m (2H, CH2), 1.25
m (2H, CH2), 0.86 t (3H, CH3). 13C NMR spectrum
(CDCl3), δC, ppm: –1.72 (SiMe3), 16.39 (CH2Si), 26.55
(CH2), 26.17 (CH2), 13.77 (CH3). Si NMR spectrum
(CDCl3), δSi, ppm: 1.6.
29
The reaction mixture contained also compounds
IIIb, IVb, and Va. The distillation of bottoms from
several syntheses gave 4.7 g of compound IIb, bp
165–170°C (4 mm Hg), nD20 1.542
2-Trimethylsilylaniline (IVa). To a solution of 8.1 g
of compound IIa in 50 ml of ether 0.046 mol of
butyllithium was added at –59 to –60°C under the
nitrogen flow, and the reaction mixture was kept for 1 h
at –40°C to –60°C. At –20°C 3.3 ml of trimethyl-
chlorosilane was added to the mixture obtained, and
the resulting mixture was left overnight. After that it
was treated at –5°C to –7°C with 40 ml of 5%
hydrochloric acid, ether layer was separated, and water
layer was extracted with ether (2 × 15 ml). Ether was
distilled off, and the residue was distilled in a vacuum
to give 2.0 g (46.6%) of product IVa with bp 104–
110°C (4–5 mm Hg), nD20 1.524.
In a reaction mixture prepared analogously from
0.01 mol of tribromoaniline and 0.8 mol of
butyllithium and worked up as described above
compounds IIf, IVd, Vb, IIId, Vc, and Vd and also
substances Xa and Xb were found.
ACKNOWLEDGMENTS
The authors express their gratitude to N.N. Khro-
mykh for performing mass spectral measurements.
2-Bromo-5-trimethylsilylaniline (IVb). A solu-
tion of the product IIb prepared from 0.029 mol of
dibromoaniline, ethylmagnesium bromide, and trime-
thylchlorosilane in 30 ml of ether according to the
above-described procedure, was treated with a solution
of 0.075 mol of butyllithium in 70 ml of ether
(dibromoaniline:butyllithium molar ratio 1:2.5) at –40
to –60°C for 1 h 40 min and kept for 1 h at this
temperature. Thereafter 4 ml of trimethylchlorosilane
were added in the course of 5 min at –30°C. The
mixture obtained was left overnight, and then 30 ml of
7% hydrochloric acid was added to it at –5°C to –10°C.
Ether layer was separated and the water layer was
extracted with ether. Combined ether solution were
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 5 2008