Synthesis and Biological Activities of Novel Fused Imidazolinones
|School||Central China Normal University|
|Keywords||imidazolones aza-Wittig reaction isothiocyanates hydrazine carbodiimide 2-arylamino-3-amino-4H-imidazol-4-ones imidazo[2 l-b]-1 3 4-thiadiazol-5(6H)-ones 5-dihydro-6H-imidazol[1 2-b]-1 2 4-triazol-6-ones 2-alkylthio-5-benzylmethene-4H-imidazol-4-ones 2H-imidazo[2 1 -b]-1 4-thiadiazin-6(7H)-ones biological activities fungicidal activities herbicidal activities|
Imidazolones have been found to show fungicidal, herbicidal, pesticidal and medicinal activities, and have the applied foreground extensively. In this paper, We studied the synthesis of novel fused imidazolones by utilizing aza-Wittig reaction that has the advantage of easily accessible starting material, mild condition and good yields. The spectral properities, biological activies and the reaction condition of imidazolones were also researched and some of them were found to show good fungicidal activies. Eighty nine unreported imidazolones in three series were synthesized . It may be summaried as follows:1.The reactions of isothiocyanates 2 with hydrazine were studied further. The results of experiments showed that the isothiocyanates reacted with hydrazine quickly at room temperature. The product was identified as 3-amino-2-thioxo-4-imidazolidinones 4 (five-membered cycle) instead of the products with six-membered cycle. 2.The cyclization of the carbodiimides 2 with hydrazine were studied. It was proved that the products were 2-arylamino-3-amino-4H-imidazol-4-ones 4 with a five-membered cycle and not its five-membered isomeric 2-hydrazino-3-aryl-4H-imidazol-4-ones or its isomeric six-membered compounds. The traditional stepwise method was impoved by a one-pot method which had the advantage of simple operation and the better use ratio of materials. This improvement found a solid base for the synthesis of fused imidazolones.3. We firstly used aza-Wittig reaction to synthesize imidazo[2,1 -b]-1,3,4-thiadiazol-5(6H)-ones at mild reaction conditions. We explored the conditions of this reactions: the compounds were synthesized with both multi-steped method and one-pot method. Both of them were comparied with each other .The mechanism was studied.4. The 3,5-dihydro-6H-imidazol[l,2-b]-l,2,4-triazol-6-ones were synthesized under very mild conditions via aza-Wittig reactions firstly. Its mechanism was investigated .The target compounds were synthesized by the uses of one-pot method .The ratio of uses of materials was greatly improved.5. On the bases of our previous work on the 2-aIkylthio-5-benzylmethene-4H-imidazol-4-ones, we have succeeded in synthesizing 2H-imidazo[2,l-b]-l,3,4-thiadiazin -6(7H)-ones by uses of intramolecular aza-Wittig reaction. The application of aza-Wittig reaction in synthesis of fused imidazolones was enlarged greatly.6. The biological activities of partial fused imidazolones were studied. The results showed that i). Imidazo[2,1-b]-l,3,4-thiadiazol-5(6H)- ones had good fungicidal activities. Especially, at 50 ppm, the fungicidal activities against Sclerotinia sclerotiorum were very prominent.ii ). 3,5-Dihydro-6H-imidazol[l,2-b]-1,2,4-triazol-6-ones had very good potential fungicidal activies, which made larger room for the future study. The fungicidal activies of 71’,7n’ and 7q’ were the best. At 50 ppm the inhibition ratios of 71’ and 7q’ against Pyricularia oryzae, Botrytis cinereapers, Sclerotinia sclerotiorum, Cibberella zeae, Cercospora beticola were all 100%. The inhibition ratio against Fusarium oxysporium also reached 9f%;at 50 ppm the inhibition ratios of 7n’ against Fusarium oxysporium , Pyricularia oryzae, Botrytis cinereapers, Sclerotinia sclerotiorum, Cercospora beticola were all 100%. The inhibition ratio against Gibberella zeae also reached 94%.The similar structure will be tested among the live plants with the fungs. iii). 2-Alkylthio-3-amino-4H-imidazoI-4-ones and 2H-imidazo[2,l-b]-l,3,4-thiadiazin -6(7H)-ones exhibited the fungicidal activities and herbicidal activities. At 10 ppm, 5b, 5k, 8c exhibited herbicidal activities against Echinochloa crusgalli. The herbicidal activities to its root were better than to its stem.