(38). To a solution of 1.0 g of crude dibromide 35 in 55 mL of CH2C12 was bubbled ammonia gas over a period of 1 h while stirring. The mixture was filtered and the filtrate was washed with water, dried (MgS04), and concentrated to afford a solid. This was twice recrystallized from benzene to give 445 mg (82% based on 29) of 38 as white needles: mp 156-158" C; NMR 6 1.21 (8, 6), 1.36 (s, 6), 5.73 (br s, 2), 6.51 (s, 1); IR (CHCl,) 3532, 3412, ...
