反应详情

A solution of 2,4-difluororesorcinol (Compound 4; 1.00 g, 8.76 mmol) and ethyl acetoacetate (1.14 g, 8.76 mmol) in 5 mL methanesulfonic acid is kept at room temperature for 24 hours, then poured into water (75 mL). The resulting precipitate is collected, rinsed with water and dried, giving 0.91 g of Compound 5 as a tan powder. An analytical sample is prepared by crystallization from light petroleum ether/methanol, giving the Compound 5 as colorless needles. UV-vis (pH 7 buffer): 358 nm, ε=17,700 cm-1M-1 ; ex/em 358/452 nm. 1H NMR (CDCl3) δ7.12 (dd, 1H), 6.27 (s, 1H), 2.38 (s, 3H). 19F NMR (CDCl3) Φ 136.5 (t, 1F), 152.8 (t, 1F).

1. customThe resulting precipitate is collected
2. washrinsed with water
3. customdried