Protectors against phytotoxic side-effects of pesticides in culture plants are compounds of formula (I) and their salts, in which R1 is hydrogen, a hydrocarbon, a hydrocarbon thio radical or a heterocyclyl radical, in which each of the four last-mentioned radicals may be unsubstituted or substituted by one or more identical or different radicals from the group halogen, cyano, nitro, amino, hydroxy, carboxy, formyl, carbonamide, sulphonamide and radicals of the formula -Z?a-Ra, R2¿ is hydrogen or (C¿1?-C4) alkyl, or R?1 and R2¿ together with the group of the formula -CO-N- are the radical of a 3 to 8-member saturated or unsaturated ring, and R3 to R5, n and m have the meanings given in claim 1. The compounds may be produced by the process claimed in claim 8.