Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
Org Biomol Chem. 2020 Feb 14;18(6):1214-1220. doi: 10.1039/c9ob02673h. Epub 2020 Jan 30.
Boric acid promoted transfer hydrogenation of substituted quinolines to synthetically versatile 1,2,3,4-tetrahydroquinolines (1,2,3,4-THQs) was described under mild reaction conditions using a Hantzsch ester as a mild organic hydrogen source. This methodology is practical and efficient, where isolated yields are excellent and reducible functional groups are well tolerated in the N-heteroarene moiety. The reaction parameters and tentative mechanistic pathways are demonstrated by various control experiments and NMR studies. The present work can also be scaled up to obtain gram quantities and the utility of the developed process is illustrated by the transformation of 1,2,3,4-THQs into a series of biologically important molecules including the antiarrhythmic drug nicainoprol.
硼酸促进取代喹啉的转移氢化反应，在温和的反应条件下，使用 Hantzsch 酯作为温和的有机氢源，生成了具有广泛合成用途的 1,2,3,4-四氢喹啉（1,2,3,4-THQs）。该方法具有实用性和高效性，其分离收率优异，且在 N-杂芳环部分可耐受还原官能团。通过各种对照实验和 NMR 研究，证明了反应参数和推测的反应机理。本工作还可以放大到获得克级产物，并且通过将 1,2,3,4-THQs 转化为一系列包括抗心律失常药物尼卡地平在内的具有重要生物学意义的分子，说明了所开发方法的实用性。
