反应详情

The above prepared 5-chloro-3-methyl-6-(piperidin-4-yloxy)-benzofuran-2-carboxylic acid ethyl ester (1.35 g, 3.32 mmol) was dissolved in 45 mL of CH2Cl2 and treated successively with cyclobutanone (0.506 g, 2 eq.), acetic acid (0.413 mL, 2 eq.) and sodium triacetoxyborohydride (1.529 g, 2 eq.), and the mixture then kept at ambient temperature for 5 h. Pouring onto crashed ice/NaHCO3, five fold extraction with AcOEt, washing with water and brine, drying over magnesium sulfate, and evaporation of the solvents, followed by followed by flash chromatography (SiO2, NEt3/AcOEt=2/98) generated 1.190 g of the title compound as white crystals.

1. additionPouring
2. extractionice/NaHCO3, five fold extraction with AcOEt
3. washwashing with water and brine
4. dry with materialdrying over magnesium sulfate, and evaporation of the solvents