1-trans-Pyrrolidine-2,4-dicarboxylic acid 2,4-Pyrrolidinedicarboxylic acid 99319-03-6 L-trans-Pyrrolidine-2,4-dicarboxylic acid Pdc-2,4 Pyrrolidine-2,4-dicarboxylate Pyrrolidine-2,4-dicarboxylic acid