Lakshmi Shanta Raj, Singh Vipin, Chowhan L Raju
Centre for Applied Chemistry, Central University of Gujarat Sector 30 Gandhinagar 382030 India
RSC Adv. 2020 Apr 6;10(23):13866-13871. doi: 10.1039/d0ra01906b. eCollection 2020 Apr 1.
Tandem conjugate addition, decarboxylation and esterification/amidation of coumarin 3-carboxylic acid derivatives with pyrazolones have been developed. The reactions were performed with coumarin 3-carboxylic acid/esters and pyrazolone in alcohol as a solvent to afford the corresponding pyrazolyl 2-hydroxy phenylpropionate derivatives. Amines and green solvents were employed for amidation in the addition reaction. The methodology has advantages such as excellent yields, a broad substrate scope, catalyst-free, easy purification by simple filtration without any workup, mild conditions and does not require any organic solvents, ligands, base or any additives. This is a green and general synthetic protocol, which could be applicable for the synthesis of substituted pyrazolyl phenyl propionate/amide derivatives. This approach demonstrates the importance of the coumarin 3-carboxylic acid/ester core structure for Michael addition.
已开发出香豆素-3-羧酸衍生物与吡唑啉酮的串联共轭加成、脱羧和酯化/酰胺化反应。反应在醇溶剂中，以香豆素-3-羧酸/酯和吡唑啉酮进行，得到相应的吡唑基2-羟基苯丙酸酯衍生物。在加成反应中，使用胺和绿色溶剂进行酰胺化反应。该方法具有产率优异、底物范围广、无催化剂、无需任何后处理，通过简单过滤即可轻松纯化、条件温和且不需要任何有机溶剂、配体、碱或任何添加剂等优点。这是一种绿色通用的合成方案，可用于合成取代的吡唑基苯基丙酸酯/酰胺衍生物。该方法证明了香豆素-3-羧酸/酯核心结构对迈克尔加成反应的重要性。
