Patent ID: 7795286

Claim:
A compound of formula (I): wherein: X denotes an oxygen atom or a group NR 1 ; Y denotes a radical (—CH 2 ) n — or —CH—(SiR′ 2 R′ 3 R′ 4 )— R 1 and R 5 independently denote a hydrogen atom a linear or branched C 1 -C 20 alkyl group; or an acyl group whose alkyl chain contains from 1 to 10 carbon atoms; R 2 , R 3 , R 4 , R′ 2 , R′ 3 and R′ 4 independently denote a linear or branched C 1 -C 20 alkyl group; and n is an integer ranging from 1 to 10.