5-fluoro-1-(tetrahydrofuran-2-yl)pyrimidine-2,4(1H,3H)-dione-13C 15N2; 5-Fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedione-13C 15N2; 1-(2-Tetrahydrofuryl)-5-fluorouracil-13C 15N2; 5-Fluoro-1-(tetrahydro-2'-furyl)uracil-13C 15N2; Citofur-13C 15N2; Coparogin-13C 15N2; Exonal-13C 15N2; FT 207-13C 15N2; Fental-13C 15N2; Fluaid-13C 15N2; Fluorafur-13C 15N2; Fluorofur-13C 15N2; Franrose-13C 15N2; Ftorafur-13C 15N2; Fulaid-13C 15N2; Fulfeel-13C 15N2;