Acetic Anhydride → N-Acetyl-4-[3E-(5-benzo[b]thiophen-2-yl-2,4-dimethoxy-phenyl)-acryloyl]-benzamide

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-[3E-(5-benzo[b]thiophen-2-yl-2,4-dimethoxy-phenyl)-acryloyl]-benzamide (Ex-93, 0.5 g, 1.13 mmol) in THF (15 mL) was cooled to −78° C. followed by addition of lithium bis(trimethylsilyl)amide (1.0 M in THF, 2.3 mL, 2.3 mmol). The mixture was stirred at this temperature for 1 hour and warmed up to 0° C. Acetic anhydride (0.48 mL, 6.8 mmol) was then added dropwise. After the addition was complete the reaction mixture was warmed up to ambient temperature and stirred for 2 hours. The reaction was quenched with water. The aqueous solution was extracted with ethyl acetate. The combined extract was washed with NH4Cl, brine, dried and concentrated. The residue was purified by flash chromatography. Elution with 50% EtOAc/hexane gave the title compound as yellow solid (0.16 g, 29%), mp 228–229° C. 1H-NMR (CCDl3) δ 8.52 (s, 1H), 8.15–8.10 (m, 3H), 7.96 (d, J=7.6 Hz, 2H), 7.85–7.77 (m, 2H), 7.67 (s, 1H), 7.55 (d, J=16.7 Hz, 1H), 7.34–7.29 (m, 3H), 6.58 (s, 1H), 4.05 (s, 3H), 4.01 (s, 3H), 2.65 (s, 3H). MS m/z=485 (M+, 100%).

Provenance & Evidence