A solution of 300 mg (0.63 mmol) of N-[5-(5-bromo-2-chloro-pyrimidin-4-ylamino)-pentyl]-3-nitro-benzenesulfonamide in 6 ml of ethanol is mixed with 600 mg of tin(II) chloride and stirred for 30 minutes at 70° C. After cooling, the reaction mixture is carefully added to ice water and made basic with saturated NaHCO3 solution. It is extracted with ethyl acetate (3×). The combined organic phases are dried (Na2SO4), filtered, and concentrated by evaporation. The remaining residue is purified by chromatography (ethyl acetate/hexane 4:1). 112 mg (0.25 mmol, corresponding to 40% of theory) of the product is obtained.
