Synthesis And Antibacterial Activities Of Benzimidazole Schiff Base Derivatives

Benzimidazole derivatives and Schiff base compounds have good biological activity andother aspects of the application, to find exellent and broad-spectrum antifungal activity of thenew fungicide. The paper synthesizes a new type of benzimidazole fragment containing iminestuctures acoording to principles of drug together. At the same time, changes substituentgroup and the substituent group position of aromatic aldehyde, bonds the two biologicalactivity groups together, then it maybe show potential typically biological activty and otheracspects of the application, desire to select out exellent activity of antifungal benzimidazolecompounds.First, the paper reviewed the recent advances in the synthesis and application ofbenzimidazoles derivatives and Schiff bases. Then o-phenylendiamine and cyanamide as rawmaterial to synthesize2-amino benzimidazole, reoccupy2-amino benzimidazole and p-nitrobenzene formaldehyde as raw material to synthesize intermediate3, intermediate3continous two-step reduction by sodium borohydride, stannous chloride for intermediate5a,finally intermediate5a and benzaldehyde derivatives were synthesized by the reaction of16no literature reports of benzimidazole and Schiff bases compunds(all compounds was testedby SciFinder Scholar). And the first step research and optimization of the reduction reactionconditions, this paper discusses the material ratio, reaction temperature and reaction time onthe yield and the effect of the experimental results show that the optimum reaction conditionis: the amount of substance of sodium borohydride as intermediate3three times, reactiontemperature as romm temperature25℃, the reaction time of24h, this reduction reaction afteroptimizaiton of separation conditions of production rate can be increased from20%to65%,the intermediate5a and16benzimidazole Schiff base compounds by MS, IR and1H-NMRverified their chemical structure, and measuring the melting point. Finally all compoundssynthesized were tested in vitro aginst six fungicide: Curvularia lunata Boedijn, Fusariumoxysporium, Pyricularia oryae Cav, Fusarium oxysporum vasinfectum, Valsa mali Miyabe etYamada, Alternaria oleracea in comparison with Thiabendazole and Azoxystrobin, get theinhibition rate of these compounds on six kinds of fungi, the results are as follows: exceptcompound6h, the rest of15compounds of Curvularia lunata Boedijn inhibition rate arehigher than that of positive contrasts probenazole, among them6a,6m and6n bacteriainhibition rate and positive contrasts its ester fairly, Compound5a,6e,6m,6n and6p of Pyricularia oryae Cav inhibition rate is higher, Compound5a,6e,6n,6p to Fusariumoxysporum vasinfectum inhibition rate were over50%, compound6n and6p inhibition rateeven more than probenazole, Compound6a,6b,6e,6f,6g,6h,6j,6m,6n,6o,6p to Alternariaoleracea inhibition rate is better also.