Maskrey Taber S, Frischling Madeline C, Rice Mikhaila L, Wipf Peter
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States.
Front Chem. 2018 Aug 24;6:376. doi: 10.3389/fchem.2018.00376. eCollection 2018.
A new multi-component condensation was discovered during the reaction of a urea, β-keto ester, and formaldehyde. In the presence of catalytic indium bromide, a Biginelli dihydropyrimidinone intermediate was further converted to a five-component condensation product through a formal hetero Diels-Alder reaction. The product structure was confirmed by NMR and NOE analysis, and the proposed stepwise mechanism was supported by the reaction of the Biginelli intermediate with ethyl 2-methylene-3-oxobutanoate.
在尿素、β-酮酯和甲醛的反应过程中发现了一种新的多组分缩合反应。在催化量的溴化铟存在下，Biginelli二氢嘧啶酮中间体通过正式的杂环Diels-Alder反应进一步转化为五组分缩合产物。通过核磁共振（NMR）和核Overhauser效应（NOE）分析确定了产物结构，并且Biginelli中间体与2-亚甲基-3-氧代丁酸乙酯的反应支持了所提出的分步反应机理。
