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. These, upon reaction with dimethylcarbonate, are selectively converted into the methyl carbamate esters MeO(O) CNH(CH 2 ) Si(OMe) , MeO(O)CNH(CH 2 ) Si (OEt) and MeO(O)CNH(CH 2 ) 2 NH(CH 2 ) Si (OMe) respectively. Carbamate MeO(O)CNH (CH 2 ) Si(OEt) is accompanied by MeO(O)CNH (CH 2 ) Si(OMe) x (OEt)3 À x formed via transesterification of the triethoxysilyl group by the co-produced methanol. The carbamation process is very selective and N-methylated species are formed in trace amounts. Conversely, the ureidofunctional silane H 2 NC(O)NH (CH 2 ) 2 NH(CH 2 ) 3 Si(OMe) 3 shows a poor reactivity towards carbamation, and, under the above conditions, N-methyl derivatives are preferably formed.

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