Russian Journal of General Chemistry, Vol. 73, No. 1, 2003, p. 157. Translated from Zhurnal Obshchei Khimii, Vol. 73, No. 1, 2003, p. 165.
Original Russian Text Copyright
2003 by Mirskov, Rakhlin, Voronkov, Gendin.
LETTERS
TO THE EDITOR
Synthesis of 1,1,5,5-Tetramethyl-3,3-diorganyltrisiloxanes
R. G. Mirskov, V. I. Rakhlin, M. G. Voronkov, and D. V. Gendin
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received April 15, 2002
1,5-Dihydrohexaorganyltrisiloxanes
(HR2SiO)2
washed with water, a solution of NaHCO3, and again
with water. The organic layer was separated and dried
over sodium sulfate. Distillation gave 90.5 g (87%) of
compound I, bp 125 127 C (720 mm), n2D0 1.3822. 1H
NMR spectrum, , ppm: 0.07 s (6H, OSiMe2O),
0.20 d (12H, Me2SiO), 4.72 m (2H, SiH).
SiR R are perspective monomers for the synthesis of
polyorganylsiloxanes, organic, and organoelement
compounds. A series of 1,1,3,5,5-pentamethyl-3-
organyltrisiloxanes was previously prepared in 30
60% yields by co-hydrolysis of organyldichlorome-
thylsilanes with excess chlorodimethylsilane at 2 4 C
[1]. The by-products of this reactions were 1,1,3,3-
tetramethyldisiloxane and 1,1,3,3,5,5-hexamethyltri-
siloxane. The latter is also formed in a low yield by
the reactions of octamethylcyclotetrasiloxane with
1,1,3,3-tetramethyldisiloxane, catalyzed by sulfuric
acid [2]. The major product of this reaction is a com-
plex mixture of , -dihydrooligodimethylsiloxanes.
Componds II V were obtained in a similar way.
Compound II. Yield 82%, bp 80 82 C (34 mm),
n2D0 1.3993. H NMR spectrum, , ppm: 0.20 d (12H,
1
Me2SiO), 0.46 q (4H, SiCH2), 0.95 t (6H, SiCCH3),
4.79 m (2H, SiH).
Compound III. Yield 94%, bp 100 102 C
(40 mm), n2D0 1.4083. H NMR spectrum, , ppm:
1
We have developed a method of synthesis of
1,1,5,5-tetramethyl-3,3-diorganyltrisiloxanes HMe2
SiOSiRR OSiMe2H (I) in yields of up to 94% by the
reaction of 1,1,3,3-tetramethyldisoxane with diorganyl-
dichlorosilanes in a 2:1 ratio in the presence of ca-
talytic amounts of water, by the following scheme.
0.15 m (15H, Me2Si, OSiMeO), 2.48 s (2H, SiCH2Cl),
4.89 m (2H, SiH).
Compound IV. Yield 80%, bp 81 83 C (4 mm),
n2D0 1.4542. H NMR spectrum, , ppm: 0.30 d (12H,
1
Me2Si), 0.36 s (3H, OSiMeO), 4.88 m (2H, SiH), 7.4
7.6 m (5H, C6H5).
(HMe2Si)2O + RR SiCl2
HMe2SiOSiRR OSiMe2H,
Compound V. Yield 89%, bp 70 76 C (76 mm),
I V
n2D0 1.3699. H NMR spectrum, , ppm: 0.16 s (3H,
1
R = R = CH3 (I), C2H5 (II); R = CH3, R = CH2Cl (III),
C6H5 (IV), CH=CH2 (V).
OSiMeO), 0.23 d (12H, Me2SiO), 4.79 m (2H, SiH),
5.95 m (3H, CH=CH2).
1H NMR spectra were measured on a Bruker DPX-
400 instrument for 5 10% solutions in CDCl3, inter-
nal reference TMS.
With increased amounts of diorganyldichlorosilane,
the yield of compound I decreases as a result of
formation of a complex mixture of oligoorganylsil-
oxanes. In the absence of water, the reaction fails to
occur even on prolonged boiling.
REFERENCES
1. Kaufman, B.L. and Karlin, A.V., Zh. Obshch. Khim.,
1,1,3,3,5,5-Hexamethyltrisiloxane (I). Water,
0.05 ml, was added to a mixture of 134 g of 1,1,3,3-
tetramethyldisiloxane and 64.5 g of dichlorodimethyl-
silane, and the resulting mixture was left to stand at
room temperature for 3 days, after which it was
1970, vol. 40, no. 7, p. 1568.
2. Zhdanov, A.A., Andrianov, K.A., Malykhin, A.P., and
Lavrukhin, B.D., Zh. Obshch. Khim., 1973, vol. 43,
no. 6, p. 1274.
1070-3632/03/7301-0157$25.00 2003 MAIK Nauka/Interperiodica