To a mixture of compound D6 (0.15 g, 0.593 mmol) and K2CO3 (0.35 g, 2.55 mmol) in 1,4-dioxane (4 ml) and DMF (1.5 ml) was added compound D7 (0.237 g, 0.85 mmol). The resulting mixture was degassed using a stream of nitrogen and to this was added Pd(PPh3)4 (0.098 g, 0.085 mmol). The reaction mixture was then subjected to microwave heating in a sealed tube at 150° C. for 10 min. The reaction mixture was cooled to room temperature and filtered through a pad of diatomaceous earth. The filtrate was concentrated in vacuo. The residue thus obtained was purified by preparative reverse phase HPLC to yield compound E1 (0.072 g, 31%).
