1 QM4 (2s,3r)-1-[7-(2-carboxyethyl)phenanthrene-2-carbonyl]piperazine-2,3-dicarboxylic acid 1.000 2 2JL (2s,3r)-1-(phenanthren-2-ylcarbonyl)piperazine-2,3-dicarboxylic acid 0.848