2-Carboxypyridine N-oxide 2-Pyridinecarboxylic acid oxide 2-Pyridinecarboxylic acid, 1-oxide 824-40-8 NSC27961 Picolinic acid 1-oxide Picolinic acid N-oxide Picolinic acid, 1-oxide Pyridine-2-carboxylic acid N-oxide