Russian Journal of General Chemistry, Vol. 71, No. 1, 2001, p. 149. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 1, 2001,
p. 163.
Original Russian Text Copyright
2001 by Grigor’ev, Voronkov, Mirskov, Rakhlin.
LETTERS
TO THE EDITOR
Reaction of Hexamethyldisilazane with Aldehydes
S. V. Grigor’ev, M. G. Voronkov, R. G. Mirskov, and V. I. Rakhlin
Favorskii Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received May 14, 2000
Hexamethyldisilazane reacts exothermically with
benzaldehyde to give N,N-dibenzylidene-C-phenyl-
methanediamine, hexamethyldisiloxane, and ammonia:
of hexane at 10 C, we added 8 g of hexamethyldisila-
zane. Within 1 min, the mixture warmed up, ammonia
evolved, and a colorless crystalline precipitate formed.
After the gas evolution ceased, the precipitate was
filtered off, and 3.5 g (70%) of N,N-dibenzylidene-C-
phenylmethanediamine (PhCH=N)2CHPh, mp 101
PhCHO + HN(SiMe3)2
(PhCH=N)2CHPh + O(SiMe3)2 + NH3.
1
102 C, was isolated. H NMR spectrum (CDCl3), ,
The presumable scheme of formation of these com-
pounds is as follows:
ppm: 8.57 s (1H, CH=N), 7.84 m (5H, C6H5 C), 7.39
m (10H, C6H5 C=N), 5.96 s (1H, CHN2). Found, %:
C 84.54; H 6.12; N 9.50. C21H18N2. Calculated, %:
C 84.52; H 6.08; N 9.39.
OH
O
SiMe3
SiMe3
SiMe3
SiMe3
RC + HN
H
RCH N
,
Reaction of hexamethyldisilazane with acetalde-
hyde. To a solution of 2.2 g of acetaldehyde in 40 ml
of hexane, cooled to 0 C, we added 8 g of hexameth-
yldisilazane and two drops of triethylchlorostannane.
The mixture warmed up, ammonia evolved, and an
orange precipitate of a polymer precipitated. Found,
%: C 46.21; H 9.38; N 11.57; Si 31.74.
OSiMe3
RCH NH
SiMe3
RCH=NSiMe3 + HOSiMe3,
Me3SiOSiMe3 + H2O,
2HOSiMe3
Reaction of hexamethyldisilazane with formalde-
hyde. To a solution of 16 g of hexamethyldisilazane
in 50 ml of hexane, we added two drops of triethyl-
chlorostannane and passed a flow of formaldehyde
generated by thermolysis of 10 g of paraform. The
reaction mixture turned yellow, ammonia evolved,
and a precipitate of a polymer formed. Found, %:
C 49.54; H 8.83; N 24.49; Si 16.49.
RCH=NSiMe3 + H2O
HOSiMe3 + RCH=NH,
CHR + NH3.
RCH=N
3RCH=NH
RCH=N
I
1
Intermediate formation of trimethylsilanol was
proved by GLC using a reference sample.
The H NMR spectra were taken on a Bruker DPX-
400 spectrometer in CDCl3, internal reference TMS.
The GLC analysis was performed with a Tsvet-500
chromatograph (thermal conductivity detector, 3000
4-mm glass columns, Inerton-Super sorbent, 0.125
0.150 mm, impregnated with 10% PMS-1000).
A similar reaction with aliphatic aldehydes and
formaldehyde occurs only in the presence of catalytic
amounts of a Lewis acid (e.g., triethylchlorostannane).
Presumably, the reaction of aliphatic aldehydes with
hexamethyldisilazane also follows the above scheme;
however, the analogs of I with R = Alk or H are un-
stable and readily polymerize [1].
REFERENCES
1. Nielsen, A.T., Atkins, R.L., Moore, D.W., Skott, R.,
Mallory, D., and La Berge, J.M., J. Org. Chem., 1973,
vol. 38, no. 19, pp. 3288 3295.
Reaction of hexamethyldisilazane with benzalde-
hyde. To a solution of 5.3 g of benzaldehyde in 50 ml
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