Leucine 3-phenyl-2-thiohydantoin, PTH-DL-Leucine Phenylthiohydantoin-DL-leucine, 5-isobutyl-3-phenyl-2-thioxo-imidazolidin-4-one, 5-Isobutyl-3-phenyl-thiohydantoin, PTH-DL-LEUCINE, 1-Phenyl-2-thioxo-4-isobutylimidazolidine-5-one, 5-Isobutyl-3-phenyl-2-thiohydantoin, 5-Isobutyl-3-phenyl-2-thioxo-4-imidazolidinone, PTH-leucine, PTH-L-LEUCINE, 5-Isobutyl-3-phenyl-2-thioxo-imidazolidin-4-on, D,L-leucine N-phenylthiohydantoin, 3-Phenyl-5-isobutyl-thiohydantoin, PHENYLTHIOHYDANTOIN-LEUCINE, 2-Thioxo-3-phenyl-5-isobutylimidazolidine-4-one