Patent ID: 8541612

Claim:
A compound of the formula I where the R1-R2 radicals are each independently selected from the group consisting of C 1 -C 16 -alkyl, C 1 -C 16 -alkenyl, C 1 -C 16 -alkoxy, C 1 -C 16 -alkenyloxy, C 3 -C 10 -cycloalkyl, C 3 -C 10 -cycloalkoxy, C 6 -C 10 -aryl, C 6 -C 10 -aryloxy, C 6 -C 10 -aryl-C 1 -C 16 -alkoxy, NR 2 R3, COR 2 , COOR 2 and CONR 2 R 3 , the R 3 radical is an allyl group and R 4 is an allyloxy group.