A mixture of the corresponding intermediate 6-(3-Bromo-phenyl)-4-(2-trimethylsilanyl-ethoxymethyl)-4,7-dihydro-1-thia-4,5-diaza-cyclopenta[a]pentalene (0.45 g, 1.0 mmol), acetamide (0.15 g, 2.5 mmol), Cs2CO3 (2 M, 3.0 mL), Xantphos (58 mg, 0.1 mmol) and Pd(OAc)2 (22 mg, 0.1 mmol) in dioxane (5 mL) was heated at 100° C. for 8 hr. The solution was cooled to room temperature and extracted with ethyl acetate. The target product was purified by gravity column chromatography (50% EtOAc in hexane) to give N-{3-[4-(2-Trimethylsilanyl-ethoxymethyl)-4,7-dihydro-1-thia-4,5-diaza-cyclopenta[a]pentalen-6-yl]-phenyl}-acetamide as brown solid in 75% yield.
