Dimethyl 2,5-dibromoterephthalate (6.09 g, 17.30 mmol) is dissolved in anhydrous THF (100 cm3), followed by the addition of 2-thienylzinc bromide (0.50 M in THF, 90 cm3, 45.0 mmol) and Pd(PPh3)4 (0.50 g, 0.43 mmol). The mixture is heated at 67° C. for 2 hours. After cooling, the reaction mixture is poured into water. The precipitate is collected by filtration and washed with water, methanol and diethyl ether then dried in vacuo, to yield the product as a pale yellow solid (5.41 g, 87%). 1H NMR (300 MHz, CDCl3): δ(ppm) 7.82 (s, 2H, Ar—H), 7.40 (dd, J=4.8 and 1.4 Hz, 2H, Ar—H), 7.07-7.12 (m, 4H, Ar—H), 3.78 (s, 6H, CH3); 13C NMR (75 MHz, CDCl3): δ(ppm) 168.1 (C═O), 140.3 (q), 133.6 (q), 133.4 (q), 131.9 (CH), 127.5 (CH), 127.0 (CH), 126.7 (CH), 52.6 (CH3); MS (m/e): 358 (M+, 100%), 327, 299, 240, 195.
