The present invention describes a process for preparing isoxazoles of the formula I where: R1 is hydrogen, C1-C6-alkyl, R2 is hydrogen, C1-C6-alkyl, R3, R4, R5 are each hydrogen, C1-C6-alkyl or R4 and R5 together form a bond, R6 is a heterocyclic ring, n is 0, 1 or 2; which comprises preparing an intermediate of the formula VI where R1, R3, R4 and R5 are each as defined above, followed by halogenation, thiomethylation, oxidation and acylation to give compounds of the formula I. Furthermore, the invention describes novel intermediates for preparing the compounds of the formula I and novel processes for preparing the intermediates.