4-Piperidinecarboxylic acid, 4-amino-1-hydroxy-2,2,6,6-tetramethyl-, zinc complex 42735-80-8 NSC239495 Zinc, bis(4-amino-4-carboxy-2,2,6,6-tetramethyl-1-piperidinyloxyato-N(4),O(4))-, (T-4)