Synthesis and fungicidal activity of tubulin polymerisation promoters. Part 1: pyrido[2,3-b]pyrazines.

Background: The excellent fungicidal activity of [1,2,4]triazolo[1,5-a]pyrimidines suggested the search for further analogues with improved properties.

Results: A series of novel trisubstituted pyrido[2,3-b]pyrazines has been designed and prepared as 6,6-biheterocyclic analogues of related 5,6-bicyclic [1,2,4]triazolo[1,5-a]pyrimidines. Their fungicidal activity was evaluated against the plant pathogens Puccinia recondita Rob.