Synthesis of the First Representatives of new 3,3a‐Dihydro‐1H‐Imidazo[4′,5′:4,5]Imidazo[2,1‐b]thia(selena)zole Heterocyclic Systems with Fungicidal Activity

Abstract

The first representatives of new fused tricyclic heterosystems, namely 3,3a‐dihydro‐1H‐imidazo[4′,5′:4,5]imidazo[2,1‐b]thiazoles and 3,3a‐dihydro‐1H‐imidazo[4′,5′:4,5]imidazo[2,1‐b][1,3]selenazoles have been synthesized through the regioselective reaction of diethyl acetylenedicarboxylate with semithioglycolurils, thioglycolurils or selenoglycolurils. Study of antifungal properties of the obtained compounds against Venturia inaequalis (V. i.), Rhizoctonia solani (R. s.), Fusarium oxysporum, Fusarium moniliforme, Bipolaris sorokiniana (B. s.) and Sclerotinia sclerotiorum phytopathogenic fungi has been performed. Tested compounds possessed good inhibition activity against R. s., B. s. with 45–94 % by mycelium growth inhibition test method, which were more active than the well–known azole fungicide triadimefon as positive control. The best active thiazole derivative was established to be effective against R. s. (94 %), B.s. (65 %) and V. i. (60 %). Two selenazole derivatives showed good activity with 69 % inhibition against R. s.