Yield:948-94-7 92.5%

Reaction Conditions:

in toluene at 100; for 2 h;

Steps:

1.1 Synthesis of N-(2,2-difluorobenzo[d][l,3]dioxol-5-yl)acetamide

A solution of 5-Amino-2,2-difiuoro-l,3-benzodioxole (26.0 g, 150.186 mmol) in dry toluene (410 ml) and acetic anhydride (16.2 ml, 1.15 eq.) was stirred at 100°C for 2 h. Subsequently, the solvent was removed under reduced pressure. The crude product was dissolved in 100 ml methanol to remove traces of acetic anhydride. The solvent was subsequently evaporated. The obtained crude product was recrystallized from toluene. The obtained product was filtered off and dried under high vacuo to obtain greyish-beige crystals (30.5 g, 92.5% yield, 98% purity). ¹H NMR (DMSO-d₆ + CCl₄): 2.04 (3H, s, CH₃), 7.20-7.23 (1H, dd, CH-arom.), 7.30- 7.33 (1H, s, CH-arom.), 7.74-7.75 (1H, d, CH-arom.), 10.12 (1H, s, NH)

References:

WO2014/1464,2014,A1 Location in patent:Page/Page column 46