1(2H)-Pyrimidinecarboxamide, 3,4-dihydro-2,4-dioxo-5-fluoro-N-(2-((2-(trimethylsilyl)ethyl)thio)ethyl)- 1-(2-((2-Trimethylsilylethyl)thio)ethylcarbamoyl)-5-fluorouracil 79281-04-2