A glycerol mediated domino reaction: an efficient, green synthesis of polyheterocycles incorporating a new thiochromeno[2,3-b]quinoline unit
作者:Narsidas J. Parmar、Hitesh A. Barad、Balvantsingh M. Labana、Rajni Kant、Vivek K. Gupta
DOI:10.1039/c3ra43205j
日期:——
One-pot synthesis of some polyheterocycles, all of which incorporate a new thiochromeno[2,3-b]quinoline unit, has been demonstrated via a domino/Knoevenagel–hetero-Diels–Alder (DKHDA) reaction, which combines a typical aldehyde substrate, 2-methyl-2-(4-methylpent-3-en-1-yl)-2H-thiopyrano[2,3-b]quinoline-3-carbaldehyde derived from 2-mercapto-quinoline-3-carbaldehyde and citral, with 5-pyrazolone, in glycerol. As evidenced by TLC (thin layer chromatography), all the new quinoline-based aldehyde substrates can be assembled with pyrazolone in a new environmentally benign glycerol as the reaction medium without a catalyst at 120 °C. The cis-fusion between the pyran and central carbocyclic (of thiochromeno) rings in all the new polyheterocycles was confirmed from both 2D NMR experiments – COSY and NOESY – and single crystal X-ray diffraction data.
通过多米诺/Knoevenagel-杂环-Diels-Alder(DKHDA)反应,展示了一锅合成一些多杂环化合物的方法,这些化合物均包含一个新的噻吩克酮[2,3-b]喹啉单元。该反应结合了一种典型的醛基底物,即来源于2-巯基喹啉-3-醛和香叶醇的2-甲基-2-(4-甲基戊-3-烯-1-基)-2H-噻吩吡喃[2,3-b]喹啉-3-醛,与5-吡唑酮在甘油中反应。薄层色谱(TLC)证实,所有的新型基于喹啉的醛基底物均可在新的环保溶剂甘油中,在无催化剂的条件下与吡唑酮反应,反应温度为120°C。所有新多杂环化合物中,吡喃环和中央碳环(噻吩克酮)的顺式结合通过二维核磁共振实验(COSY和NOESY)以及单晶X射线衍射数据得到了证实。