391 mg (0.91 mmol) of N-ethyl-4-[1-(4-methoxybenzyl)-3-(3-nitrophenyl)-1H-pyrazol-4-yl]pyrimidin-2-amine were dissolved in a mixture of 20 ml of dioxane and 4 ml of water. 239 mg (3.64 mmol) of metallic zinc and 485 mg (9.1 mmol) of ammonium chloride were then added to the resulting solution. The reaction was carried out at 100° C. under stirring for 5 hours. The suspension was then filtered through a celite pad and the filtrate evaporated in vacuo. The residue was partitioned between dichloromethane and aqueous sodium hydrogenocarbonate and the organic layer dried over sodium sulphate and concentrated to give a crude purified by flash-chromatography on a silica gel column (CH2Cl2-CH3COCH3; from 9/1 to 7/3), affording 340 mg (93%) of the title compound.
