Compounds of formula (I) or pharmaceutically veterinarily or agriculturally acceptable sails thereof, or pharmaceutically, veterinarily or agriculturally acceptable solvates of either entity, wherein R1 is 2,4,6-trisubsituted phenyl or 3,5-disubstituted pyridin-2-yl R3 is C1-C4 alkyl optionally substituted with hydroxy or with one or more halo cyano, C1 to C5 alkanoyl or phenyl R5 is hydrogen, C1 to C4 alkyl, amino or halo R2 and R4 are each independently selected from hydrogen, C, to C„ alkyl, fluoro, chloro and bromo or, together with the carbon atom to which they are attached, form a C3 to C6 cycloalkyl group R6 and R8 are each independently selected from hydrogeri, C1 to C4 alkyl, fluoro, chloro and bromo or when R2 and R4 do not form part of a cycloalkyl group, R2 and R6 together with the carbon atoms to which they are attached, may form a C5 to C7 cycloalkyl group and R7 is hydrogen, C1 to C4 alkyl optionally substituted with one 01 more halo or C1 to C4 alkoxy are parasiticidal agents,
