Hydantoin461-72-3100 % similar Dihydrouracil504-07-457 % similar 2,5-Diketopiperazine106-57-053 % similar 5-Hydroxyuracil496-76-450 % similar Thiohydantoin503-87-750 % similar 2-Azetidinone930-21-235 % similar L-Dihydroorotic acid5988-19-234 % similar Dihydrothymine696-04-833 % similar 2-Pyrrolidone616-45-532 % similar Glycylglycylglycine556-33-231 % similar Thiobarbituric acid504-17-631 % similar Barbituric acid67-52-731 % similar 2-Piperidinone675-20-731 % similar