| 摘要 |
Compounds having the formula <IMAGE> wherein R1 and R2 are lower alkyl or together lower alkylene, R3 is hydrogen, alkyl, methoxyethyl, alkenyl, propargyl, benzyl, alkyl substituted benzyl, or acyl, R4 is alkylene of 1 to 4 carbon atoms substituted with alkyl or alkenyl of 1 to 18 carbon atoms, alkenylene of 1 to 4 carbon atoms, cycloalkylene, cycloalkenylene, bicycloalkylene, bicycloalkenylene, or phenylene, M is hydrogen or a metal, and z has a value of from 1 to 4, and either (a) R5 is alkyl of 1 to 6 carbon atoms, R6 is alkyl of 1 to 6 carbon atoms, and R7 and R8 are independently hydrogen or alkyl of 1 to 5 carbon atoms, provided that R7 and R8 are not both hydrogen, or (b) R5 and R6 are together lower alkylene and R7 and R8 are independently hydrogen or alkyl of 1 to 5 carbon atoms, are good light stabilizers. The carboxylic acids are prepared for example, from 2,3,6-trimethyl-2,6-diethylpiperidin-4-ol and 1,2-cyclohexanedicarboxylic anhydride to give 2,3,6-trimethyl-2,6-diethyl-4-piperidyl hydrogen 1,2-cyclohexanedicarboxylate. The metal salts of the acids are readily prepared by reacting the acids or their salts with a reactive form of the metal or metal complex.
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