"3,5-Difluoro-4-hydroxybenzylidene imidazolidinone" . . . . . . . . "(5Z)-5-[(3,5-Difluoro-4-hydroxyphenyl)methylene]-3,5-dihydro-2,3-dimethyl-4H-imidazol-4-one" . . "3,5-Difluoro-4-hydroxybenzylidene imidazolidinone" . . . . . . . . . .