(1(2H),5'-Bipyrimidine)-2,2',4,4'(1'H,3H,3'H)-tetrone, 5,5'-difluoro-5',6'-dihydro-6'-hydroxy- 1-(5'-Fluoro-6'-hydroxy-5',6'-dihydrouracil-5'-yl)-5-fluorouracil 142237-28-3 Hdfu-5-FU