反应详情

Intermediate I-17a was prepared from 5-amino-1-(4-bromo-2-fluoro-phenyl)-6,7-difluoro-4-hydroxy-1,3-dihydro-benzoimidazol-2-one (I-14a: 600 mg, 1.6 mmol), 1,1,1-triethoxy-ethane (5 mL) and p-toluene sulfonic acid (100 mg) using procedures analogous to those described above for Intermediate I-16a to afford 350 mg of the product (54.68% yield). H1NMR (DMSO-d6, 300 MHz): δ 12.40 (s, 1H), 7.90 (dd, 1H), 7.72-7.60 (m, 2H), 2.68 (s, 3H).