Synthesis And Evolution Of Thiourea Derivative Analogs Urease Inhibitors

About half of the world population is infected with Helicobacter pylori（Hp）.H.pylori infection can cause various diseases such as gastritis and gastric ulcer.Urease is the main toxic factor,so urease inhibitor is expected to be a first-line drug for diseases caused by Helicobacter pylori infection.A series of urease inhibitors thiourea were designed by combining thiourea or thiosemicarbazide core,with benzoic acid,phenylacetic acid or benzaldehyde fragment to molecular skeleton.Two suitable routes determined by exploring the reaction conditions.Benzoic acid or phenylacetic acid reacted with thionyl chloride at 90℃for1 hour,then combined with thiourea at 100℃for 1.5 hours.The benzaldehyde is condensed with thiosemicarbazide in methanol,then reduced with sodium borohydride in tetrahydrofuran.3 compounds with good inhibitory activity were screened by urease inhibition activity tested,which were a20(IC₅₀=0.19±0.01μmol/L)、c4(IC₅₀=0.14±0.04μmol/L)and c14（IC50=0.22±0.01μmol/L）,All the inhibitory activity was higher than that AHA(IC₅₀=27.21±2.69μmol/L).To elucidate Surface Plasmon Resonance（SPR）and molecular simulation techniques were used to analyze the action mechanism,the KD values of compounds a20,c4 and c14 were（1.01±0.17）×10^-2μM、（2.40±0.18）×10^-2μM and（1.43±0.09）×10^-2μM,it shows the binding rate are much larger than the dissociation rate.The molecular simulation techniques show that these 3 compounds directly interact with the urease active center and bind to the amino acid residues in the urease cavity,providing the support for their good urease inhibitory activity.The toxic effects of the 250μg/mL compounds on HepG2 cells,SGC-7901 cells and K562 cells were evaluated by MTT and CCK8.The cell death rate of HepG2 cells and SGC-7901cells was mostly low than 20%,and the cell death rate of K562 cells was mostly low than 30%.