A mixture of 0.04 gram (catalyst) of tri-2-furylphosphine and 0.04 gram (catalyst) of tris(dibenzylidineacetone)dipalladium(0) in 30 mL of N,N-dimethylformamide is purged with dry nitrogen gas and stirred at ambient temperature for five minutes. After this time 1.2 grams (0.0048 mole) of 2,4-diamino-5-iodo-6-methylpyrimidine (prepared in Step B of Example 3) is added in one portion. The reaction vessel is then immersed in an oil bath that is preheated to 60° C. where it is maintained for about five minutes. After this time, 3.1 grams (0.0064 mole) of 1,1-difluoro-1-(4-chlorophenyl)-3-tributylstannyl-2-propene is added in one portion to the reaction mixture. The reaction mixture is again purged with dry nitrogen gas, and the oil bath temperature is brought to 80°-85° C. where it is maintained for about 18 hours. After this time the reaction mixture is diluted with 200 mL of water and extracted with two 200 mL portions of ethyl acetate. The combined extracts are then washed with three 100 mL portions of an aqueous solution of 5% lithium chloride. The organic layer is concentrated under reduced pressure to a residue. The residue is purified by column chromatography, yielding 2,4-diamino-6-methyl-5-[3,3-difluoro-3-(4-chlorophenyl)-1-propenyl]pyrimidine.
