Catalysis by Lithium Perchlorate Enables Double-Conjugate Addition of Electron-Deficient Maleimides to 2-Aminopyridines and 2-Aminothiazoles

Abstract

Lithium perchlorate has been found to catalyze the conjugate addition of maleimides with 2-aminopyridines and 2-aminothiazoles. The reaction proceeds under mild conditions leading to the corresponding double adducts in good yields. A plausible mechanism of this reaction has been proposed.

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GRAPHICAL ABSTRACT

Keywords:

• Bis-adducts
• conjugate addition
• lithium perchlorate
• maleimides

ACKNOWLEDGMENTS

We are grateful to Olexandr V. Turov, Magdalina D. Tsapko, and Olexandr Petin for help with NMR studies.

Notes

^a For all products, the yields are given after recrystallization.