The present invention relates to a process for the preparation of compounds of formula (I) wherein R1 and R2 are each independently of the other hydrogen or C1-C5alkyl and R3 is CF3 or CF2H, by a) reaction of a compound of formula (II) wherein R1 and R2 are as defined for formula (I), with at least one reducing agent to form a compound of formula (III) wherein R1 and R2 are as defined for formula (I), and b) reaction of that compound with at least one reducing agent to form a compound of formula (IV) wherein R1 and R2 are as defined for formula (I), and (c) reaction of that compound with a compound of formula (V) wherein Q is chlorine, fluorine, bromine, iodine, hydroxy or C1-C6alkoxy and R3 is as defined for formula (I), to form the compound of formula (I); and to novel intermediates for use in that process.