Synthesis of six heterocyclic multifunctional alkylating agents and evaluation of their activity againstPyrenophora avenae andBlumeria graminis f.sp.hordei

Six heterocyclic alkylating agents were synthesized and examined for activity against the oat stripe pathogenPyrenophora avenae on agar plates and against the barley powdery mildew fungusBlumeria graminis f.sp.hordei on barley seedlings. Radial growth ofP. avenae was not significantly affected by any of the compounds, but four of them,α,α-bis4,7-bis(2-chloroethyl)-1,4,7-triazacyclononane]-para-xylene3], 1,4,8,11-tetra(2-chloroethyl)-1,4,8,11-tetraazacyclotetradecane4], 8,11-bis(2-chloroethyl)-1,4,8,11-tetraaza-5,7-oxocyclotetradecane5] and 7,16-bis(2-chloroethyl-1,4,10,13-tetraoxa-7,16-diazaoctadecane6], gave significant reductions in biomass ofP. avenae grown in liquid culture and in powdery mildew infection on barley when used at 25μM. Polyamine biosynthesis was examined by following the incorporation of labeled ornithine into polyamines inP. avenae. The four compounds3–6 which reduced mildew infection all reduced the flux of label through to the polyamines inP. avenae. Whether the reductions in mildew infection caused by these compounds is related to reduced formation of polyamines is not known and awaits investigation. http://www.phytoparasitica.org posting May 22, 2005.