A Regioselective Synthesis of 6-Alkyl- and 6-Aryluracils by Cs2CO3- or K3PO4-Promoted Dimerization of 3-Alkyl- and 3-Aryl-2-Propynamides

作者:Rajapaksha Suranga M; Mlsna Todd E*; Pittman Charles U Jr*
来源:Journal of Organic Chemistry, 2017, 82(11): 5678-5688.
DOI:10.1021/acs.joc.7b00508

摘要

A regioselective synthesis of 6-alkyl- and 6-aryluracils was developed by the dimerization of 3-alkyl- and 3-aryl-2-propynamides promoted by either Cs2CO3 or K3PO4. A range of 3-aryl-2-propynamides, with both electron-deficient and electron-rich 3-aryl substituents, were successfully reacted in high yields. Cs+ acts as a soft Lewis acid to polarize the carbon-carbon triple bond, and solid K3PO4 interacts with carbonyl oxygen, promoting intermolecular nucleophilic attack by the only weakly nucleophilic amide nitrogen. Experiments were conducted to support the proposed mechanism.

  • 出版日期2017-6-2

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