To a vial containing 2-amino-6-bromo-8-(trans-4-methoxycyclohexyl)-4-methylpyrido[2,3-d]pyrimidin-7(8H)-one (75 mg, 0.20 mmol), 2-methoxy-5-pyridineboronic acid (37.5 mg, 0.245 mmol) and cesium carbonate was added PdCl2(dppf)1:1 w/CH2Cl2 followed by 5:1 dimethoxyethane:water (3 mL, degassed by bubbling with argon). The vial was capped and heated in the microwave for 30 minutes at 100° C. The reaction mixture was concentrated and the crude product was purified by flash chromatography eluting with chloroform/methanol (0-5%). The fractions containing the desired product were concentrated and the solids were triturated with methyltertbutyl ether to afford 2-amino-8-(trans-4-methoxycyclohexyl)-6-(6-methoxypyridin-3-yl)-4-methylpyrido[2,3-d]pyrimidin-7(8H)-one (33 mg, 40%).
