Patent ID: 8114996

Claim:
A method of synthesizing a compound of formula I, wherein R1, R2 are, independently, chloro or fluoro, and wherein R3 is H, alkyl, aralkyl or is an alkylether or alkylthioether, the alkyl moiety being linear or branched, comprising the steps of firstly reducing a diazenyl compound of formula II wherein R1, R2, R3 are defined as above, n=0 to 5 and wherein each R4 n , independently, is halogeno or is alkyl or alkoxy, non-catalytically or with a catalytic amount of an homogenous organic, non-metal catalyst to the corresponding hydrazo compound of formula III and in a second step catalytically hydrogenating said hydrazo compound III with a heterogeneous Ni-catalyst to the compound of formula I.