1,8-Dioxo-octahydro-xanthenes are easily prepared via the condensation of aldehydes with 1,3-cyclohexadione and/or dimedone using N-sulfonated DABCO as a new and efficient catalyst. This reagent is also efficiently able to catalyze the condensation of aldehydes with barbituric acid leading to 5-arylmethylene-pyrimidine-2,4,6-triones. The structure of the products was characterized by their IR, 1H NMR, and 13C NMR spectroscopy. The present methodology offers several advantages such as ease of preparation and handling of the catalyst, high yields, simple and green procedure, low cost, short reaction times, easy work-up, and preformation of the reaction in the absence of solvent or in water as a green solvent.
1,8-二氧杂-八氢化咕吨类化合物可通过醛与
1,3-环己二酮和/或
双甲酮在新型高效的N-磺化
DABCO催化剂作用下缩合反应制得。该试剂同样能高效催化醛与
巴比妥酸的缩合反应,生成5-芳亚甲基-
嘧啶-2,4,6-三酮。产物结构通过其红外光谱、核磁共振氢谱和碳谱得以表征。本方法具有多种优势,如催化剂制备与处理简便、产率高、操作简单且环保、成本低、反应时间短、后处理简便,以及可在无溶剂条件下或使用
水作为绿色溶剂的情况下预先进行反应。