反应详情

The above prepared 5-hydroxy-benzofuran-2-carboxylic acid ethyl ester (1.50 g, 7.27 mmol) was dissolved in 36 mL of THF and treated successively at 10° C. with 1-isopropyl-piperidin-4-ol (1.46 g, 1.4 eq.), triphenylphosphine (2.67 g, 1.4 eq.) and DIAD (2.00 mL, 1.4 eq.), and the mixture then kept at ambient temperature for another 3 h. Pouring onto crashed ice/NH4Cl, twofold extraction with AcOEt, washing with water and brine, drying over magnesium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, NEt3/AcOEt=2/98), yielded finally 1.36 g of the title compound as light yellow oil.

1. additionPouring
2. extractionice/NH4Cl, twofold extraction with AcOEt
3. washwashing with water and brine
4. dry with materialdrying over magnesium sulfate, and evaporation of the solvents