| abstract |
1-Hydroxypyrazole derivatives of the formula (I) <IMAGE> (I) where A is <IMAGE> n is 0 or 1, R1, R2 and R3 independently of one another are each hydrogen, chlorine, bromine or iodine, R4 is hydrogen, a straight-chain or branched, open-chain alkyl, alkenyl or alkynyl radical, a cyclic alkyl, alkenyl or alkynyl radical or aryl or aralkyl, and the radicals R4 which are capable of substitution may furthermore be monosubstituted or polysubstituted by halogen, haloalkyl, haloalkoxy, alkyl, alkoxy, alkoxycarbonyl, -OH, =O, -COOH or salts of this, -NO2 or -CN, have a nitrification-inhibiting action. Substances where R4 is not hydrogen when n is 0 are novel. |