| Synthesis and antibacterial activity of Novel thioureas containing l,3,4-thiadiazole was studied by testing target compounds on the part of the inhibition of bacteria and fungus plants.The resistance of non-system infected tobacco(Nicotiana tabacum cv.Xanthi一nc)inoculated by Novel thioureas containing 1,3,4-thiadiazole were investigated and the best target compounds were screened out.The results showed that:1.Synthetic process of the target compoundsAccording to molecular design of the compound,2-amino-5-S-hydrocarbon-1,3,4-thiadiazole was synthesized with thiosemicarbazide and carbon disulfide as starting material under the condition of heating reflux.The four 1,3,4-thiadiazole derivatives,obtained by substitution with 2-amino-5-S-hydrocarbon-l,3,4-thiadiazole and Bromoethane,Allyl chloride,Bromobutane,Bromo-hexane.And twelve new N-heterocyclic thiourea compounds were synthesized by 1,3,4-thiadiazole derivatives and Ethyl isothiocyanate,allyl isothiocyanate,trifluoromethyl phenyl isothiocyanate.Their chemical structure and molecular weight were confirmed by IR,1H-NMR,13C-NMR and HRMS spectra and elemental analyses.2.Inhibition of the arget compounds against bacteria and fungiThe antibacterial activity of the target compounds to Salmonella,staphylococcus aureus,escherichia coli were tested by the Haloes methods.The results showed that,some of them exhibited antibacterial activity at the concentration 500 ug/ml.In salmonella test,the inhibitory effect of compound IV4,IV7 is stronger and Ⅳ5,Ⅳ8 without inhibition.In staphylococcus aureus test,the inhibitory effect of compound Ⅳ 3,IV 4,IV 7,Ⅳ 8 showed stronger.But in escherichia coli test,compound Ⅳ1～Ⅳ8 had no inhibition effect.On the whole,inhibitory effect of the target compounds on bacteria growth is very weak.The antifungal activity of the target compounds to Curvularia lunata,Cotton Fusarium Wilt,P.parasitica var nicotianae,Fusarium spp.were tested by the mycelial growth rate method.The results showed that the target compounds on fungal growth inhibitory effect is better.In the resistance of Curvularia lunata test,the inhibition rate of Compound Ⅳ6,Ⅳ10,Ⅳ12 at the concentration 500 μg/mL reached 72.18%,72.39%,71.68%,increasing 10.53%,10.74%,10.03%over triadimefon(61.65%)respectively.In the resistance of Cotton Fusarium Wilt test,the inhibition rate of Compound Ⅳ6 reached 72.27%and compared with potions triadimefon(65.73%)increased by 65.69%.In the resistance of Fusarium spp.test,the inhibition rate of Compound Ⅳ6 reached 71.53%and compared with potions triadimefon(65.69%)increased by 65.69%.In the resistance of P.parasitica var nicotianae test,only the inhibition rate of CompoundⅣ10,Ⅳ11 was higher than triadimefon increasing 1.39%and 1.79%respectively,but the difference was not significant.3.Resistance test of the target compounds against TMVUnder the condition of potted,The resistance of non-system infected tobacco(Nicotiana tabacum cv.Xanthi—nc)inoculated by Novel thioureas containing 1,3,4-thiadiazole was investigated to screen out the best target compounds.The results showed that,all test agents showed some inhibitory effect to TMV and the highest inhibition rate was 41.09%of compoundⅣ12 when spraying agent after inoculating TMV for 12h on Xanthi—nc at the concentration 500μg/mL.when inoculating TMV after spraying agent for 24h on Xanthi—nc,the prevention effect of compound Ⅳ10,Ⅳ12 reached 69.98%and 74.38%,which was better than tningnanmycin increasing 4.04%and 9.44%respectively.Under the condition of potted,The change trend of chlorophyll content,SOD,CAT,POD,PPO,PAL within the leaf tobacco was studied on Nicotiana tabacum K326.The results showed that,at the concentration 500 μg/mL,the tobacco plants treated by selected compounds could produce signals associated with disease resistance mechanism,which promoting tobacco produced in the department of defense enzyme and restraining the degradation rate of chlorophyll in the leaves,thereby enhancing the disease resistance of plants. |
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