Synonyms: 3-Pyrrolin-1-yloxy,3-carboxy-2,2,5,5-tetramethyl- (7CI,8CI); 1-Oxyl-2,2,5,5-tetramethylpyrroline-3-carboxylicacid; 2,2,5,5-Tetramethyl-1-oxypyrroline-3-carboxylic acid;2,2,5,5-Tetramethyl-3-carboxy-3-pyrroline-1-oxyl;2,2,5,5-Tetramethyl-3-pyrroline-1-oxyl-3-carboxylic acid;2,2,5,5-Tetramethylpyrroline-1-oxyl-3-carboxylic acid; 3-Carboxy-2,2,5,5-tetramethyl-1-pyrrolinyloxyl;3-Carboxy-2,2,5,5-tetramethyl-3-pyrroline-1-oxyl;3-Carboxy-2,2,5,5-tetramethylpyrroline-1-oxyl; PCAOL