Patent ID: 6903239

Claim:
A process for preparing compounds of the formula (I) where R 1 is in each case independently C 1 -C 12 -alkyl, chlorine or bromine or a radical of the formulae (IIa) or (IIb) A-B-D-E (IIa) A-E (IIb) where, each independently, A is absent or is a C 1 -C 8 -alkylene radical and B is absent or is oxygen, sulphur or NR 2 where R 2 is hydrogen or C 1 -C 8 -alkyl and D is a carbonyl group and E is C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy, NH(C 1 -C 8 -alkyl) or N(C 1 -C 8 -alkyl) 2 or is a cyclic amino radical having 4 to 12 carbon atoms and n is an integer of 0 to 3-m and R F is fluorine, C 1 -C 12 -fluoroalkyl, —O(C 1 -C 12 -fluoroalkyl) or —S(C 1 -C 12 -fluoroalkyl) and m is an integer of 1 to 3, comprising converting a compound of the formula (II) where R 1 and R F , and also n and m, are as defined above in the presence of urotropin and in the presence of acid to compounds of the formula (I).