Facile Synthesis and Herbicidal Activity of Novel Multisubstituted Pyridine Derivatives

摘要

Ketene N,S-acetals reacted with beta-ketoesters in the presence of Zn(NO3)(2) center dot 6H(2)O 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.