has role is protonated form of anticoronaviral agent brequinar A quinolinemonocarboxylic acid that is quinoline substituted by 2'-fluoro[1,1'-biphenyl]-4-yl, methyl, carboxy and fluoro groups at positions 2, 3, 4, and 6, respectively. It is an inhibitor of dihydroorotate dehydrogenase, an enzyme that is required for <em>de novo</em> pyrimidine biosynthesis. The compound exhibits antineoplastic and antiviral properties. CHEBI:177387 brequinar(1-) biphenyls monocarboxylic acid quinolinemonocarboxylic acid antimetabolite antineoplastic agent immunosuppressive agent pyrimidine synthesis inhibitor EC 1.3.5.2 [dihydroorotate dehydrogenase (quinone)] inhibitor monofluorobenzenes