Facile synthesis and herbicidal activity of novel multisubstituted pyridine derivatives

Abstract

Ketene N,S-acetals reacted with b-ketoesters in the presence of Zn(NO 3 ) 2 Á 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.

An expedient synthesis of novel bis[thienopyridines] linked to arene or heteroarene core as novel hybrid molecules

“…9 The pyridine structure is present in many natural compounds like nicotinic acid (vitamin B3) and pyridoxine (vitamin B6) and also in many drugs (Figure 1). Pyridines are also exploited in agrochemistry 10,11 as well as in materials science. 12 Different methodologies for construction and functionalization of pyridine derivatives have been recently reviewed.…”

A Modular Synthesis of Functionalized Pyridines through Lewis‐Acid‐Mediated and Microwave‐Assisted Cycloadditions between Azapyrylium Intermediates and Alkynes

“…With the access to the (trifluoromethyl)‐ and acryloyl‐substituted pyridines 3k and 3l we have successfully extended the collection of highly functionalized pyridines. It is known that pyridine derivatives of this type are potentially useful compounds as pharmaceuticals 2s,3i,20…”

Metal-Free Multicomponent Syntheses of Pyridines

“…Thus, this nucleus constitutes a major scaffold to create antitumor or antiviral drugs. Alternatively, pyridines are also exploited in agrochemistry for their herbicide, insecticide, and antifungal properties. As a consequence, chemists have developed a plethora of methods to elaborate this structure, and most of them have been compiled in a series of reviews .…”