| abstract |
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 comprising the steps of firstly reducing a diazeny compound of formula (II) 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 in with a heterogeneous Ni-catalyst to the compound of formula (I). |