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
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