反应详情

温度

95 °C

Add acetic anhydride (166 kg, 1625 mol) to a mixture of ethyl 4,4-difluoroacetoacetate (33 kg, 199 mol) and triethyl orthoformate (60 kg, 407 mol) maintained at 90-100° C. Stir the mixture at 90-100° C. for 8.5 hours and remove ethyl acetate using a Dean-Stark apparatus. Concentrate the reaction mixture to give the title compound (37.8 kg, 86% yield, 97% GC purity). 1H NMR (500 MHz, CDCl3,) δ 7.88 (d, J=6 Hz, 1H), 6.3 (m, 1H), 4.3 (m, 4H), 1.4 (m, 3H), 1.32 (m, 3H).

1. customremove ethyl acetate using a Dean-Stark apparatus
2. concentrationConcentrate the reaction mixture