An efficient catalyst free synthesis of nitrogen containing spiro heterocycles via [5 + 1] double Michael addition reaction
作者:Komal Aggarwal、Kanika Vij、Jitender M. Khurana
DOI:10.1039/c4ra00521j
日期:——
2,4-Diazaspiro[5.5]undecane-1,3,5,9-tetraones and 3-thioxo-2,4-diazaspiro[5.5]undecane-1,5,9-triones have been synthesized via double Michael addition of 1,5-diaryl-1,4-pentadien-3-one with active methylene compounds such as N,N-dimethyl barbituric acid, barbituric acid, thio-barbituric acid and N,N-diphenyl thiobarbituric acid in ethylene glycol at 100 °C in the absence of any catalyst to give high yields within a short reaction time. The structure has been confirmed by X-ray analysis. The single-crystal structure of the diazaspiro compound revealed that the CAr–H⋯π, π–π stacking and intermolecular hydrogen bonding interactions act as major driving forces for crystal packing.
通过1,5-二芳基-1,4-戊二烯-3-酮与活性甲烷化合物(如N,N-二甲基巴比妥酸、巴比妥酸、硫代巴比妥酸和N,N-二苯基硫代巴比妥酸)在100°C的无催化剂乙二醇中进行双迈克尔加成反应,合成了一系列2,4-二氮杂螺[5.5]十一烷-1,3,5,9-四酮和3-硫代-2,4-二氮杂螺[5.5]十一烷-1,5,9-三酮,产率高且反应时间短。结构通过X射线分析得到确认。二氮杂螺化合物的单晶结构揭示,CAr–H⋯π、π–π堆积和分子间氢键相互作用是晶体堆积的主要驱动力。