Palladium(II) acetate (1 mg, 4.5 μmol) was added to a degassed suspension of 6-bromo-2-(4-phenyl-butyl)-3H-pyrido[2,3-d]pyrimidin-4-one (20 mg, 55 μmol; example 26), cyclopropyl boronic acid (10 mg, 110 μmol), potassium phosphate (59 mg, 275 μmol) and tricyclohexylphosphine (3 mg, 9 μmol) in toluene (360 μl) and water (24 μl) under an argon atmosphere. The reaction mixture was heated for 14 h to 100° C. and poured onto ice cold isopropyl acetate/brine 1/1. The layers were separated, the aqueous layer was extracted two times with isopropyl acetate, the combined extracts were washed with brine and dried over sodium sulfate. Removal of the solvent under reduced pressure left a yellow solid which was purified by preparative thin layer chromatography (silica gel, isopropyl acetate/heptane) to give 6-cyclopropyl-2-(4-phenyl-butyl)-3H-pyrido[2,3-d]pyrimidin-4-one (1 mg, 3.1 μmol; 6%) as yellow crystals. MS: m/e=320.2 [M+H+].
