A mixture of 1 (0.132 g, 0.264 mol) and well-ground anhydrous K2CO(0.146 g, 1.06 mol) in DMF (2.5 ml) was stirred under argon at 70 C for 72 h. Then, the reaction was cooled down to about 40C,and poured into water (6 ml) with stirring for several minutes. The mixture was filtered in vacuum, washed with water twice and dried to give yellow solid