This compound has been obtained by two similar ways: 1. The reaction of 5-iodouracil (I) with trimethylsilylacetylene (II) by means of PdCl2(PPh3)2 and CuI2 in TEA/DMF gives 5-(trimethylsilylethynyl)uracil (III), which is then desilylated with sodium methoxide or NaOH in methanol. 2. The reaction of 5-iodouracil (I) with POCl3 at 120 C catalyzed by N,N-diethylaniline gives 2,4-dichloro-5-iodopyrimidine (IV), which by reaction with NaOMe in methanol is converted into 2,4-dimethoxy-5-iodopyrimidine (V). The condensation of (V) with trimethylsilylacetylene by means of PdCl2(PPh3)2 and CuI2 in TEA/DMF yields 2,4-dimethoxy-5-(trimethylsilylethynyl)pyrimidine (VI), which is treated with NaI and Tms-Cl in refluxing acetonitrile to afford 5-(trimethylsilylethynyl)uracil (III).