CHEMISTRY

Academician K. A. ANDRIANOV, N. V. DELAZARI,
L. M. VOLKOVA, N. A. CHUMAEVSKII

SYNTHESIS AND SPECTRA OF TRIMETHYLALKYL-(PHENYL, CHLORO)-1-OXA-2,6-DISILACYCLOHEXANES

Recently, interest has increased in various heterocyclic compounds. Among carbocyclosiloxanes there have been described methyldiphenyl-1-oxa-2,5-disilacyclopentanes (¹, ²), tetramethyl-1-oxa-2,6-disilacyclohexane (³), C-substituted tetramethyl-1-oxa-2,6-disilacyclohexanes (⁴), tetramethyl-1-oxa-1,7-disilacycloheptane (⁵), 2,2,4,4-tetramethyl-3-oxa-2,4-disilabicyclo-(3,2,2)-nona-6,8-diene (⁶), and

\[ \mathrm{CF_2} \begin{matrix} \diagup & \mathrm{CF_2C_6H_4Si(CH_3)_2} & \diagdown \\ & & \mathrm{O} \\ \diagdown & \mathrm{CF_2C_6H_4Si(CH_3)_2} & \diagup \end{matrix} \tag{7} \]

In the present work, new trimethylalkyl-(phenyl, chloro)-1-oxa-2,6-disilacyclohexanes were obtained in 60–80% yield by hydrolysis of bis-(alkylchlorosilyl)-propanes with an aqueous solution of potassium hydroxide

\[ \mathrm{Cl(CH_3)_2SiCH_2CH_2CH_2Si(CH_3)(R)Cl} \xrightarrow[\ ]{\mathrm{H_2O,\ KOH}} \]

\[ \longrightarrow \begin{matrix} & \mathrm{CH_2} & \\ / & & \backslash \\ \mathrm{CH_2} & & \mathrm{CH_2} \\ | & & | \\ \mathrm{(CH_3)_2Si} & & \mathrm{Si-(CH_3)} \\ \backslash & & | \\ & \mathrm{O} & \mathrm{R} \end{matrix} \qquad \mathrm{R = CH_3\ (I),\ C_3H_7\ (II),\ C_4H_9\ (III),} \]

\[ \mathrm{C_6H_5\ (IV),\ Cl\ (V).} \]

On heating an ether solution of 1-dimethylchlorosilyl-3-methyldichlorosilylpropane with sodium bicarbonate, a bicyclic compound was obtained according to the equation

\[ \mathrm{Cl_2(CH_3)Si(CH_2)_3Si(CH_3)_2Cl} \xrightarrow{\mathrm{NaHCO_3}} \]

\[ \longrightarrow \begin{matrix} & \mathrm{CH_2} & & & & \mathrm{CH_2} & \\ / & & \backslash & & / & & \backslash \\ \mathrm{CH_2} & & \mathrm{CH_2} & & \mathrm{CH_2} & & \mathrm{CH_2} \\ | & & | & & | & & | \\ \mathrm{(CH_3)_2Si} & & \mathrm{Si} & - & \mathrm{O} & - & \mathrm{Si} & \mathrm{Si-(CH_3)_2} \\ \backslash & & / & & & & \backslash & / \\ & \mathrm{O} & \mathrm{CH_3} & & & \mathrm{CH_3} & \mathrm{O} \end{matrix} \tag{VI} \]

Bis-(alkylchlorosilyl)-propanes were obtained by the reactions

\[ \mathrm{CH_3SiCl_3 + RMgBr \rightarrow CH_3(R)SiCl_2,} \tag{a} \]

\[ \mathrm{CH_3RSiCl_2 + CH_2{=}CHCH_2MgBr \rightarrow CH_3(R)ClSiCH_2CH{=}CH_2,} \tag{b} \]

\[ \mathrm{CH_3(R)ClSiCH_2CH{=}CH_2 + HSi(CH_3)_2Cl} \xrightarrow{\mathrm{H_2PtCl_6}} \]

\[ \mathrm{\rightarrow Cl(CH_3)(R)SiCH_2CH_2CH_2Si(CH_3)_2Cl,} \tag{c} \]

\[ \mathrm{R = CH_3,\ C_3H_7,\ C_4H_9,\ C_6H_5,\ Cl.} \]

The properties of the newly synthesized substances are presented in Table 1. In the IR absorption spectra of carbocyclosiloxanes I–VI, of interest is the shift of the frequencies of the Si—O—Si vibrations in comparison with the frequencies of these vibrations in the case of hexaalkyldisiloxanes, hexamethylcyclotrisiloxane

Table 1

and cyclosiloxanes of the type

\[ \begin{array}{c} \begin{array}{cc} R & \mathrm{CH_3}\\[-2mm] \diagdown & \diagup\\[-1mm] & \mathrm{Si}\\[-1mm] \diagup & \diagdown\\[-1mm] \mathrm{CH_2} & \mathrm{CH_2}\\[-1mm] | & |\\[-1mm] (\mathrm{CH_3})_2\mathrm{Si} & \mathrm{Si}(\mathrm{CH_3})_2\\[-1mm] \diagdown & \diagup\\[-1mm] & \mathrm{O} \end{array} \qquad R=\mathrm{CH_3},\ \mathrm{C_2H_5},\ \mathrm{C_6H_5}. \end{array} \tag{XIII} \]

For carbocycloxiloxanes I—IV the frequency of the \(\mathrm{Si—O—Si}\) vibrations is 990 (for V, \(\nu(\mathrm{Si—O—Si}) = 1000\ \mathrm{cm}^{-1}\)) and 646 \(\mathrm{cm}^{-1}\), instead of 1060—1070 and 520—550 \(\mathrm{cm}^{-1}\) for hexaalkyldisiloxanes or 1016 and 606 \(\mathrm{cm}^{-1}\) for hexamethylcyclotrisiloxane.

Fig. 1. Infrared absorption spectra of cyclosiloxanes

For cyclosiloxanes of type XIII one of the \(\mathrm{Si—O—Si}\) vibration frequencies is equal to 1018 \(\mathrm{cm}^{-1}\). For compound VI, \(\nu(\mathrm{Si—OSi})\) lie near 990 (ring) and 1080 \(\mathrm{cm}^{-1}\) (linear \(\mathrm{Si—OSi}\) bond). The vibration frequencies that may be assigned to various groups bonded to the silicon atom, for compounds I—VI, coincide with the frequencies and assignments from work (8): \(\mathrm{Si—CH_3}\) 1255—1258 \(\mathrm{cm}^{-1}\) (I—VI); \(\mathrm{Si(CH_2)_3Si}\) 900—907, 931—934, 1020—1022, and 1091—1095 \(\mathrm{cm}^{-1}\) (I—VI); \(\mathrm{Si—C_3H_7}\)-\(n\) 1213 \(\mathrm{cm}^{-1}\); \(\mathrm{Si—C_4H_9}\)-\(n\) 1198 \(\mathrm{cm}^{-1}\); \(\mathrm{Si—C_6H_5}\) 1118 \(\mathrm{cm}^{-1}\) (see Fig. 1).

Experimental Part

Methylpropylallylchlorosilane (VII). The Grignard reagent, prepared from 81 g (0.67 mole) of allyl bromide, was added to 105 g (0.67 mole) of methylpropyldichlorosilane in 150 ml of ether. The mixture was heated for 5 h, the precipitate was filtered off, and the filtrate was distilled on a column; 30.4 g of VII was obtained, b.p. 163–164°, yield 34%.

VIII was obtained analogously.

1,3-Bis-(dimethylchlorosilyl)-propane (IX). 52.5 g (0.39 mole) of dimethylallylchlorosilane, 36.8 g (0.42 mole) of dimethylchlorosilane, and 1 g of 0.1 N \( \mathrm{H_2PtCl_6} \) solution in iso-\(\mathrm{C_3H_7OH}\) were heated in a three-necked flask equipped with a stirrer, thermometer, and efficient reflux condenser. At 65° a vigorous reaction began, and the temperature rose to 123°. The mixture was boiled for 3 h at 131° and fractionated on a column; 61.6 g of IX was obtained, b.p. 118–119°/141 mm, yield 68%.

Compounds X, XI, XII were obtained analogously.

2,2,6-Trimethyl-6-butyl-1-oxa-2,6-disilacyclohexane (III). To a cooled solution of 14 g (0.25 mole) of KOH in 100 ml of water, at 5°, 22.9 g (0.1 mole) of 1-dimethylchlorosilyl-3-methylbutylchlorosilylpropane in 200 ml of ether was added; the mixture was stirred for 1 h, the ether layer was separated, washed with water, and dried over \( \mathrm{Na_2SO_4} \); on fractionation, 2.5 g of III was isolated, b.p. 76–78°/2 mm, yield 69.4%.

Compounds I–IV were obtained analogously.

2,2,6-Trimethyl-6-chloro-2,6-disilacyclohexane (V). To a mixture of 9.91 g (0.07 mole) of KOH, 20 ml of acetone, and 20 ml of ether, 8.8 g of \(\mathrm{Cl_2CH_3Si(CH_2)_3Si(CH_3)_2Cl}\) and 5 drops (0.12 ml) of water were added, and the mixture was stirred for 6 h at room temperature. On the following day the precipitate was filtered off, and from the filtrate 4.5 g of V was isolated with b.p. 75–80°/28 mm, yield 58.4%; the redistilled product had b.p. 67°/25 mm.

Bicyclic siloxane (VI). To 7.4 g (0.088 mole) of \( \mathrm{NaHCO_3} \), 40 ml of ether, and 0.18 ml of water, with stirring, 11 g (0.044 mole) of \(\mathrm{Cl_2(CH_3)Si(CH_2)_3Si(CH_3)_2Cl}\) was added over 30 min; vigorous evolution of \( \mathrm{CO_2} \) was observed. Then 2 g of \( \mathrm{Na_2SO_4} \) was added, and the mixture was stirred for 1 h at room temperature and 1 h at 35°. The precipitate was separated, and from the filtrate 4.6 g of VI was isolated, b.p. 150–153°/27 mm, yield 62.5%; the redistilled product had b.p. 142°/21 mm.

The IR spectra of I–VI were investigated on two spectrophotometers: VIKS M-3 with an NaCl prism (700–1500 cm\(^{-1}\)) and IKS-14 with a KBr prism (400–700 cm\(^{-1}\)); the substances were recorded as a thin layer between tightly pressed salt windows.

Institute of Organoelement Compounds
Academy of Sciences of the USSR

Received
26 X 1964

Cited Literature

1. W. A. Piccoli, G. Haberland, R. L. Merker, J. Am. Chem. Soc., 82, No. 8, 1833 (1960).
2. R. L. Merker, U. S. Pat., 3 041 362, 1962; RZhKhim, 23T 209, 1963.
3. M. Kumada, A. Habuchi, J. Inst. Polytechn. Osaka City Univ., 3C, 65 (1952); Chem. Abstr., 48, 9907 (1954).
4. W. Simmler, H. Niederprüm, W. Helmut, Chem. Ber., 97, No. 4, 1047 (1964).
5. L. H. Sommer, G. R. Ansul, J. Am. Chem. Soc., 77, 2482 (1955).
6. D. R. Weyenberg, L. H. Toporeer, J. Am. Chem. Soc., 84, No. 14, 2843 (1962).
7. S. A. Fugua, R. M. Silverstein, J. Org. Chem., 29, No. 2, 395 (1964).
8. N. A. Chumaevskii, Usp. Khim., 32, No. 9, 1152 (1963).