| abstract |
Compounds of the formula I wherein R 1 , R 2 , R 3 and R 4 , independently of each other, are C 1 -C 8 alkyl or C 1 -C 5 hydroxyalkyl, or R 1 and R 2 together with the carbon atom they are attached to are C 5 -C 12 cycloalkyl, or R 3 and R 4 together with the carbon atom they are attached to are C 5 -C 12 cycloalkyl; R5, R 6 , R 7 , R 8 and R 9 , independently of each other, are H, C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 5 -C 12 aryl, C 1 -C 4 haloalkyl, an electron withdrawing group, or C 6 -C 12 aryl which is substituted by a residue selected from C 1 -C 4 alkyl, C 1 -C 4 alkoxy, halogen; and R 7 and R 8 together may also form a chemical bond; and R is an organic linking group containing 2-500 carbon atoms and forming, together with the carbon atoms it is directly connected to and the nitrogen atom, a substituted, 5-, 6 or 7-membered cyclic ring structure, are prepared by oxidizing a compound of the formula II The compound of the formula I can be hydrogenated and/or halogenated by conventional methods. Compounds of the formula I and the corresponding hydrogenated and/or halogenated Compounds are well suitable as stabilizers for organic material against degradation by light, oxygen and/or heat or yellowing; some are also active as flame retardants. |