以硅胶键合N-丙基哌嗪基丙酸钠为可循环催化剂合成3,4-二氢吡喃c苯并吡喃衍生物和香豆素(英文)

摘要

A simple and efficient procedure for the preparation of silica-bonded N-propylpiperazine sodium n-propionate(SBPPSP) by the hydrolysis of silica-bonded N-propylpiperazine methyl n-propionate(SBPPMP) in hydrochloric acid(0.5 mol/L) followed by treatment with saturated sodium bicarbonate is described.The SBPPMP was obtained by the reaction of 3-silica-bonded N-propylpiperazine and methyl acrylate in methanol.SBPPSP was used as a recyclable basic catalyst for the synthesis of 3,4-dihydropyrano[c]chromenes by the reaction of aromatic aldehydes,malononitrile,and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.Biscoumarins were also obtained via condensation of aldehydes and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.The catalyst could be recycled several times without any additional treatment.