Novel Zinc Ion–Catalyzed Synthesis of Unsymmetric Multisubstituted Pyridines

Abstract

A facile and convenient synthesis of unsymmetric multisubstituted pyridines from β-ketoesters and ketene N,S-acetals or ketene N,N-acetals has been achieved in good yields catalyzed by Zn(NO₃)₂·6H₂O in the presence of triethylbenzylammonium (TEBA) chloride in ethanol. This reaction was carried out under economical, one-pot reaction conditions (using easily obtained starting materials, and inexpensive catalyst and solvent) and offers considerable improvements over traditional methodology.

ACKNOWLEDGMENTS

This project was supported by the National Key Project for Basic Research Development Program of China (No. 2003CB114400), the National Natural Science Foundation of China (No. 20772042), the National Science and Technique Foundation of China (No. 2006BAE01A01-10), and Syngenta Ltd.

Notes

^a Yield of pure isolated product.

^a Yield of pure isolated product.

^a Yield of pure isolated product.