Abstract: The invention relates to compounds of the general formula wherein Ar1, Ar2, R4, R5, R6, R7, R8, W, X, a and b have the significances given in the specification, and optionally the enantiomers thereof. The active ingredients have advantageous pesticidal properties. They are especially suitable for controlling parasites on warm-blooded animals.

Abstract: Compounds of the formula (I), wherein R1 is aryl or biaryl; R2 is aryl-lower alkyl, biaryl-lower alkyl, benzo-fused cycloalkyl, cycloalkyl-lower alkyl, bicycloalkyl-lower alkyl, aryloxy-lower alkyl, or aryl-C2-C7-alkyl in which C2-C7-alkyl is interrupted by Y; Y is O, S, SO, SO2, CO or NR6; R3 is hydrogen or lower alkyl; or R2 and R3 combined are C2-C7-alkylene or C2-C7-alkylene interrupted by Y; R4 is hydrogen or lower alkyl; R5 is hydrogen, optionally substituted lower alkyl, aryl-lower alkyl, biaryl-lower alkyl, cycloalkyl-lower alkyl, bicycloalkyl-lower alkyl, aryloxy-lower alkyl, or aryl-C2-C7-alkyl in which C2-C7-alkyl is interrupted by Y; R6 is hydrogen, lower alkyl or aryl-lower alkyl; and pharmaceutically acceptable salts thereof, which are useful as cysteine cathepsin inhibitors