Yield: 81%

Reaction Conditions:

with iron;ammonium chloride in methanol;water at 80; for 16 h;

Steps:

To a solution of intermediate 74 (2 g, 0.012 mol) in H20/MEOH 1: 1 (40 mL), were added NH4CI (2.2 g, 3.5 eq. ) and Fe powder (2.3 g, 3.5 eq. ). The reaction mixture was stirred at 80°C for 16 hr. Fe was then filtered and washed with MeOH. The MeOH was evaporated, H20 was added and the aqueous solution was extracted with EtOAc (3X50 mL). The combined organic extracts were dried over anh. NA2SO4, the solids were filtered and the solvent evaporated to dryness to give the title compound (1.35 g, 81 %) as a brown oil. NMR ('H, CDCI3) : 8 6.9 (d, 1 H), 6.4 (d, 1 H), 3.8 (s, 3H), 2.33 (s, 3H).

References:

SB PHARMCO PUERTO RICO INC;NEUROCRINE BIOSCIENCES INC;GLAXO GROUP LIMITED WO2004/62665, 2004, A1 Location in patent:Page/Page column 45