无溶剂条件下氨基磺酸锂催化合成氧杂蒽化合物

LiNH_2SO_3 Promoted Synthesis of 1,8-Dioxo-octahydroxanthene Under Solvent-free Conditions

在无溶剂条件下,芳香醛与5,5-二甲基-1,3-环己二酮或1,3-环己二酮经氨基磺酸锂催化缩合反应合成了氧杂蒽.结果表明,当催化剂用量为3%(摩尔分数)时,在120℃反应40～70 min,产率高达90%以上.此外,探讨了该反应的氨基磺酸锂催化机理.该合成方法具有操作简单、反应时间短、产率高及对环境友好等优点,是现有氧杂蒽化合物合成方法的一个重要补充.

An efficient synthesis of 9-aryl-1,2,3,4,5,6,7,8-octahydroxanthene-1,8-dione via condensation of aromatic aldehydes with 5,5-dimethyl-1,3-cyclohexanedione or cyclohexane-1,3-dione using LiNH2SO3 as an eco-friendly catalyst under solvent-free condition was described.The results indicate that the yields is up to 90% when using 3%（molar fraction） LiNH2SO3 and reacting at 120 ℃ for 40—70 min.Furthermore,a proposed reaction mechanism for the reaction catalyzed by LiNH2SO3 was speculated.The present methodology offers several advantages such as excellent yields,simple procedure,short reaction time and mild conditions making it an important supplement to the existing methods.