p-Toluenesulfonic acid → 6-(4-Bromo-2-fluoro-phenyl)-4,5-difluoro-6,8-dihydro-imidazo[4',5':3,4]benzo[1,2-d]oxazol-7-one

Participants

Reaction Steps

Intermediate I-16a was prepared from 5-amino-1-(4-bromo-2-fluoro-phenyl)-6,7-difluoro-4-hydroxy-1,3-dihydro-benzoimidazol-2-one (I-14a: 800 mg, 2.14 mmol), triethyl orthoformate (3.7 mL) and p-toluene sulfonic acid (80 mg) using procedures analogous to those used to prepare Intermediate I-15a above to afford 550 mg of the product (65% yield). H1NMR (DMSO-d6, 300 MHz): δ 12.50 (s, 1H), 8.80 (s 1H), 7.97 (d, 1H), 7.65-7.55 (m, 2H). HPLC: 95.7%

Provenance & Evidence