The present invention relates to compounds of the formula (I) wherein R1 and R2 independently of one another are hydrogen, C1-C10-alkyl, C1-C10-haloalkyl, C3-C10-cycloalkyl, C3-C10-halocycloalkyl, C2-C10-alkenyl, C2-C10-haloalkenyl or together represent an aliphatic chain, or the like R3 is halogen, cyano, C1-C8-alkyl, C1-C8-haloalkyl, C3-C8-cycloalkyl, C3-C8-halocycloalkyl, C2-C8-alkenyl, C2-C8-haloalkenyl, C1-C8-alkoxy, phenyl, or the like R4 is hydrogen, C1-C10-alkyl, C1-C10-haloalkyl, C3-C8-cycloalkyl, C3-C8-halocycloalkyl, C2-C10-alkenyl, C2-C10-haloalkenyl, phenyl, or the like t is 0 or 1 p is 0, 1, 2, 3 or 4. The present invention also relates to a process for preparing a compound of the formula (I) which comprises reacting a compound of the formula II with a compound of the formulae III or IV: where t, p, R1 R3, R3 and R4 are as defined in any of claims 1 to 6 and where A&minus is an equivalent of an anion having a pKB of at least 10 (determined under standard conditions in water).
