A mixture of spray-dried KF (135 mg, 2.3 mmol), intermediate 8 (120 mg, 0.23 mmol) and catalytic amount of 18-crown-6 in DMSO (5 mL) was stirred at 95-100° C. for 15 min. Work-up of the reaction mixture as described in example 1 gave the product as a yellow color solid (57 mg, 65%), mp 142-144° C. 1H NMR (400 MHz, CDCl3): δ 8.15 (1H, t, J=7.8 Hz), 7.78 (1H, dd, J=10.8, 1.6 Hz), 7.71 (1H, d, J=8.4 Hz), 6.70 (1H, br s), 4.86 (2H, s), 4.44 (2H, d, J=5.2 Hz); LC-MS (negative ion mode): m/z 371, 373 (M−H)−.
