1-(Hydroxymethyl)-5,5-dimethylhydantoin116-25-6100 % similar 1,5,5-Trimethyl-2,4-imidazolidinedione6851-81-658 % similar Benzonal744-80-931 % similar 1-Methylhydantoin616-04-631 % similar Dimethadione695-53-431 % similar Alloxantin76-24-431 % similar