Methoxy chlorosilane

Methoxy- and hydrosilanes are reduced at lower values than chlorosilanes. Additionally, the reduction seems to proceed very slowly, because the measured current density is low in comparison with the chlorosilanes. 

Dimethoxypyrimidines can be considered model alternatives to 1,3-dimethyluracil. After chemical treatment of the pyramidine nucleus, both protecting methoxy groups are easily removed with the aid of trimethyl-chlorosilane to give substituted uracils (82JHC463 90S243) (Scheme 20). 

Reactions with methoxysilanes (Figure 3) and HMDS (Figure 4) produce similar results to the chlorosilanes. The methoxy function, either as Ti-O-Me, Si-O-Me, or MeOH (see below), generates bands at 2840 and 1450 cm l. Ammonia, the byproduct from HMDS, produces new peaks at 3390, 3345, 3240, 3150, and 1600 cm l. 

Methoxy- and ethoxy-chlorosilanes were separated on columns packed with Rysorb or Chemosorb coated with Se-30, FS-60, Carbowax 6000, Apiezon L or DC-550 with nitrogen as carrier gas414. 

Kirichenko and Markov separated and identified methoxy- and ethoxy-chlorosilanes. They studied the behaviour of these compounds on columns (1 or 2 metres x 3mm) packed with Rysorb or Chemasorb coated with SE-30 FS-60, Carbowax 6000, Apiezon L or DC-550 with nitrogen (40 - 50ml per minute) as carrier gas. Separation was best on the polar stationary phase. 

In Equation 149, the chlorosulfonation occurs, as expected, in the / ara-position relative to the electron-donating (-f I) methylene moiety and simultaneously the three chlorine atoms attached to the silicon atom are sequentially substituted by chlorosulfonate and methoxy groups to give the methylsulfonate 470. In this context, it is well known ° that chlorosilanes react with chlorosulfonic acid to yield the corresponding chlorosulfonate esters, as occurs in the first stage of the conversion shown (Equation 149). 

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