Synthesis And Bioactivity Of Novel 1,3,4 - Thiadiazole Amide Compounds

Taking the special character of 1,3,4-thiadiazole amide into consideration, two synthetic routes were designed to afford a series of 1,3,4-thiadiazole amide derivatives through steps of separation and purification. And then those target products had been identified by IR spectrum, NMR spectrum and MS spectrum.The antibacterial activities of some target compounds on Ralstonia solanacearum and Xanthomonas oryzae pv.oryzae were tested by the nephelometry method at 200 μg/mL in vitro. The results demonstrated that some of 1,3,4-thiadiazole amide derivatives carrying heterocycle groups, such piperazine, morpholine, pyrrole, exhibit good activities in inhibition of Xanthomonasoryzaepv.oryzae. However, most of compounds are more than standard reagent Bismerthiazol(54.4%) in inhibitions at the concentration of 100 μg/mL in vitro. Meanwhile, there are seven compounds(Ⅰ1, Ⅰ2, Ⅰ4, Ⅰ5, Ⅰ6, Ⅰ13, Ⅰ14) perform better inhibitions, all of which are more than 80%. In order to further determination, these seven compounds had done in testing EC50, The results are 47.1 μg/mL(Ⅰ1), 17.5 μg/mL(Ⅰ2), 59.8 μg/mL(Ⅰ4), 19.8 μg/mL(Ⅰ5), 43.0 μg/mL(Ⅰ6), 41.5 μg/mL(Ⅰ13), 22.8 μg/mL(Ⅰ14), respectively. Which are less than standard reagent Bismerthiazol(92.6 μg/mL) in inhibition.The half leaf dry spot method was used to test against Tobacco mosaic virus(TMV) activity of the target compounds. The preliminary bioassay results indicated the compounds(Ⅰ16,Ⅰ17) containing morpholine showed certain antiviral activity against TMV at a concentration of 500 mg/L. In terms of curative effect, compounds Ⅰ16 andⅠ17 respectively exhibited inhibition at 57.0, 50.2%, which are lower than standard reagent Ningnanmycin(62.7%).