The general procedure for the synthesis of 5-amino-6-methyl-2-cyanopyridine from zinc cyanide and 2-bromo-5-amino-6-methylpyridine was as follows: first, 6-cyano-2-methyl-3-aminopyridine was prepared; 3.5 g (18.6 mmol) of 6-bromo-2-methyl-3-aminopyridine, 352 mg (0.37 mmol) of tris(benzylideneacetone)dipalladium(0) , 532 mg (0.92 mmol) of 1,1 '-bis(diphenylphosphino)ferrocene, 146 mg (2.2 mmol) of zinc powder and 1.4 g (12 mmol) of zinc cyanide were mixed in 70 ml of N,N-dimethylacetamide. The reaction mixture was stirred at 20°C for 22 hours. After completion of the reaction, the reaction mixture was diluted with 200 ml of ethyl acetate and washed with 2N ammonium chloride solution. Note: Decantation was only possible after filtering the mixture on a Celite-type filter aid. The resulting organic phase was washed with sodium chloride solution, dried with magnesium sulfate and concentrated under reduced pressure. The evaporated residue was purified by silica gel chromatography using a dichloromethane/ethyl acetate mixture (9/1; v/v) as eluent, resulting in 1.6 g of 5-amino-6-methyl-2-cyanopyridine in the form of a yellow powder (yield = 65%). The melting point was 192-196 °C.
