5.36 g (16 mmol) of (4,5-dichloro-6-piperazin-1-yl-pyrimidin-2-yl)-methyl-amine dihydrochloride and 3.86 g (16 mmol) of trans-4-(2-oxoethyl)cyclohexyl-carbamic acid tert-butyl ester were dissolved in dichloromethane (320 ml). 6.7 ml (48 mmol) triethylamine was added, then 5.1 g (24 mmol) sodium triacetoxyborohydride was added portion wise and the reaction mixture was stirred for 20 hours at ambient temperature. 20% potassium carbonate solution in water (100 ml) was then added. The organic layer was separated, dried and evaporated to dryness in vacuo. The residue was triturated with diethyl ether to give the title compound (6.9 g, 88.5%), melting point: 199-202° C.
