Abstract: Fungicidal pyrimidine derivatives and the use as a fungicide of the compounds of formula (1): wherein R1 is H, C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl C3-C6cycloalkyl, C1-C6alkoxy, C3-C6cycloalkoxy, C1-C6alylthio, C1-C6alkylsulfinyl, C1-C6alkylsulfonyl, phenyl, pyridinyl or azolyl groups, (being optionally substituted by one or more substituents); or N(R4)C(O)R5, R2 is polyfluoroalkyl, R3 is fluorine, chlorine, bromine or iodine; ethenyl or ethynyl (being optionally substituted by one or more of halogen), R4 and R5 are, independently, H, C1-C6alkyl, C2-C6alkenyl or C2-C6alkynyl groups, (being optionally substituted by one or more of halogen or cyano); or R4 and R5 can join together to form a 5 or 6-membered ring, Q is a heteroaromatic ring selected from the following ring system; imidazol-1-yl, pyrazol-1-yl, 1,2,3-triazol-1-yl, 1,2,3-triazol-2-yl, 1,2,4-triazol-1-yl, 1,2,4-triazol-1-yl, benzimidazol-1-yl or tetrazol-5-yl groups, (being optionally substituted by one or more of substituents).