| 摘要 |
A process is disclosed for the preparation of the substantially pure compound of formula (I) comprising catalytic hydrogenation of a compound of formula (II) wherein R6 and R7 are independently selected from (i) wherein Ra and Rb are independently selected from hydrogen, loweralkyl and phenyl and Rc, Rd and Re are independently selected from hydrogen, loweralkyl, trifluoromethyl, alkoxy, halo and phenyl; and (ii) wherein the naphthyl ring is unsubstituted or substituted with one, two or three substituents independently selected from loweralkyl, trifluoromethyl, alkoxy and halo; or R6 and R7 taken together with the nitrogen atom to which they are bonded are (a) or (b) wherein Rf, Rg, Rh and Ri are independently selected from hydrogen, loweralkyl, alkoxy, halogen and trifluoromethyl; or an acid addition salt thereof.
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