Abstract: The invention relates to triazolopyrimidines of the formula I in which the index n and the substituents R, R1, R2 and X are as defined below: X is nitro, a group —C(S)NR3R4, a group —C(?N—OR5)(NR6R7) or a group —C(?N—NR8R9)(NR10R11), R is halogen, cyano, hydroxyl, cyanato, alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, alkoxy, alkenyloxy, alkynyloxy, haloalkoxy, cycloalkyl, cycloalkenyl, cycloalkoxy, alkoxycarbonyl, alkenyloxycarbonyl, alkynyloxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoximinoalkyl, alkenyloximinocarbonyl, alkynyloximinoalkyl, alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, cycloalkylcarbonyl, or a five- to ten-membered saturated, partially unsaturated or aromatic heterocycle which contains one, two, three or four heteroatoms from the group consisting of O, N or S; R1 is alkyl in which one carbon atom may be replaced by a silicon atom, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, or a five- to ten-membered saturated, partially unsatura