Research On The Synthesis And Antibacterial Activities Of Mannich Base Containing Thiadiazole

With in-depth study of heterocyclic compounds, heterocyclic compoundswich regarded as the efficient compounds has become the main direction of thenew drug research development.1,3,4-thiadiazole compounds as a class ofheterocyclic intermediates in drug applications,which have the potential andvalue.Containing three heteroatoms1,3,4-thiadiazole derivatives have goodinsecticidal, fungicidal, herbicidal, plant growth regulators and variety ofbiological activity and pharmacologocal activity.1,3,4-thiadiazole oxadiazolering substituentshave a certain influence, especially in biological activity. TheMannich reaction can be used to synthesize nitrogen-containing organic matterand biological activity of some significant value. In this paper, draw on the basisof previous experience,1,3,4-thiadiazole participate in Mannich reaction, thehetero atom ring different substituents to design a series of novel compounds,and show efficient antibacterial activity. Carry out the work of the following fourareas:（1）A series of compounds were synthesized.2-amino-5-aryl-1,3,4-thiadiazole by phosphorus oxychloride method to optimize the synthesisprocess improvement, the yieds are improved compared with the literature.Thestructure of the compounds were confirmed by IR and elemental analysis.（2）Under the condition of strong hydrochloric acid as catalyst,four2-amino-5-alkyl-1,3,4-thiadiazole were synthesized. The structure of thecompounds was confirmed by IR and elemental analysis.（3）On the basis of extensive literature research, a series of previousunreported disubstituted thiadiazoles were designed and synthesized.The effectof the amount of catalyst and reaction time to the yied were studied, the optimalsynthesis conditions were determined. All compounds were characterized andconfirmed by elemental analysis, IR,¹HNMR,¹³CNMR.（4）Anhydrous aluminum chloride as catalyst, ethanol as solvent, maintained at atemperature of45℃,2-amion-5-aryl（alkyl）-1,3,4-thiadiazol anddisubstituted2-amion-1,3,4-thiadiazole as the raw material and Mannich reactionof acetophenone form aldehyde synthesised Mannich base. And to study the typeof solvent, reaction temperature, reaction time on the yield, to determine theoptimum conditions of synthesis. All compounds were characterized byelemental analysis, IR analysis. The structure of the compounds was confirmed.（5）The experiment of antibacterial activity is studied on11kinds ofdifferent Mannich base containing thiadiazole. The experimental of preliminarystudy of the antibacterial activity compared2-amino-5-aryl （alkyl）-1,3,4-thiadiazole or bisubstituted2-amino-1,3,4-thiadiazol, the experimental resultsshowed that the same test conditions, the Mannich base with thiadiazoles showedgood antibacterial activity.