Ascosonchine, the enol tautomer of 4-pyridylpyruvic acid with herbicidal activity produced by Ascochyta sonchi.

Abstract

A new phytotoxic enol tautomer of 4-pyridylpyruvic acid, named ascosonchine, was isolated from the culture filtrate of Ascochyta sonchi. Such a leaf pathogen is a potential biocontrol agent of Sonchus arvensis, a perennial herbaceous weed occurring throughout the temperate regions of the world. Ascosonchine, characterised as (Z)-2-hydroxy-3-(4-pyridyl)-2-propenoic acid by spectroscopic methods, showed selective herbicidal properties, that are not associated with antibacterial, antifungal or zootoxic activities. We report the isolation and the chemical and biological characterisation of ascosonchine (1), the (Z)-2-hydroxy-3-(4-pyridyl)-2-propenoic acid produced by Ascochyta sonchi, and showing interesting selective herbicidal properties, not associated to antibacterial, antifungal or zootoxic activities.