Stereoisomers thereof, veterinary or pharmaceutically acceptable salts thereof, compositions thereof and their use as a parasiticide in an animal. Claim 1: A compound of formula (1) wherein each of R1a, R1b and R1c is independently selects from hydrogen, halo, cyano, C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 alkoxy, C 0-6 alkyl-C 3-6 cycloalkyl and C 1-6 haloalkoxy； R2 is H, C1-6alkyl, C0-6alkyl-phenyl, C0-6alkyl-heteroaryl, C0-6alkyl-C3-6alkyl, or C0-6alkyl-heterocycle； R3 is H, C1-6 alkyl, C0-6 alkyl-C3-6 cycloalkyl, C2-6 alkenyl, C0-6 alkyl-phenyl, C1-4-O-phenyl alkyl, C0-6 alkyl-heterocycle or C0- alkyl 6-heteroaryl；Each R2 and R3 C1-6 or c0-6-cycloquilo C3-6 tar may be optional and replaced by at least one alternative selected between cyanogen, halogenated, hydroxy, oxo, alcox C1-6, halogenated alcoxi C1-6, C1-6, s (or) PRC, SH, s (or) pnrab, nrarb, nrab (or) Rb, SC (or RC), scn-c (or ARB) NR, respectively. Among R2 and R3 c0-6-phenyl, c0-6-isomerized tar or other c0-6-isomerized tar, R2 and R3 can be replaced by at least one selected substitute between cyanogen, halogenated, oxo, = s, = NRD, hydroxy, alcox C1-6, C1-6 tar, C1-6, SH, - S (o) PR, halogenated oxygen C1-6, het and phenyl； R is the pitch of C1-6 or cycloquilo C3-6,Each substitute is replaced by at least one halogen； RA is hydrogen, C1-6 or c0-3-cycloquilo C3-6 tar, in which tar and liquid crystal tar can be replaced by cyanide or at least one halide； Rb is hydrogen, C1-6 tar, cycloquilo C3-6, c0-3-phenyl tar, C0-3-isomerized tar or c0-3-isomerized tar, where chemically feasible, each alternative shall be replaced by at least one alternative selected between hydroxyl, cyanogen, halogenated O-S (or) PR； or an alternative containing RA and Rb with N atoms,they can form a 4-7 membered ring that can optionally include at least one additional heteroatom selected from N, O, and S； Rc is C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 haloalkyl-C3-6 cycloalkyl, C0-3 alkyl-C3-6 cycloalkyl, C0-3 alkyl, phenyl, C0-3 alkyl-heter
