Benzonitrile, 4-bromo- → 6-(4-bromophenyl)-5H-thieno[3,2-c]pyridin-4-one

To a solution of N-methyl-2-methylthiophene-3-carboxamide (13.0 g) in tetrahydrofuran (130 ml) was dropwise added 2.5 M butyl lithium (74 ml) at −70° C. The reaction solution was stirred at −70° C. for 2 hr, followed by the addition of 4-bromobenzonitrile (15.3 g) at once. After the dry ice/acetone bath was removed, the reaction mixture was back to room temperature. Three hours later, an aqueous solution of saturated ammonium chloride and ether were added thereto, and then the resulting mixture was further stirred for 1 hr. The resulting white precipitates were collected by filtration, and washed with water, ether and n-hexane in this order. The resulting product was dried to give the title compound (4.9 g, yield; 19%).