Facile synthesis and herbicidal activity of novel multisubstituted pyridine derivatives

Abstract

Abstract magnified imageKetene N,S‐acetals reacted with β‐ketoesters in the presence of Zn(NO3)2 · 6H2O as catalyst, in ethanol solvent, giving 6‐alkylsulfanylpyridines 4 in good yields without complicated purification procedures. Oxidization of compounds 4 with aqueous hydrogen peroxide in the presence of catalytic sodium wolframate led to the formation of 6‐alkylsulfonylpyridine derivatives 5, which could be further derivatized in the 6‐position by nucleophilic reactions with phenols or amines to give multisubstituted pyridine compounds 8. Bioassays indicated that some of the compounds of the type 8 have good herbicidal activity at a dose of 100 mg/L on the roots of oil rape and barnyard grass. J. Heterocyclic Chem., (2010).