Study On Synthesis Of Albendazole And Redox Reaction By Microorganism

The dissertation was contained three chaptersIn first chapter,2-nitro-4-thiocyanatoaniline was used as raw material.The cyano group was firstly deacylated to obtain 2-nitro-4-thioaniline salt under basic conditions,followed S-alkylation by the addition of an appropriate amount of n-propylbromide to produce 2-nitro-4-propylthioaniline using alcohol as solvent.2-nitro-4-propylthioaniline was reduced using Raney Nickel as catalyst to diamine compound.Finally,4-propylthio-o-diamine was cyclized with cyanidemethylcarbamatetogettheproductof5-propylthio-1H-benzimidazole-2-carbamic acid methyl ester under acidic conditions.Under optimal conditions,the total yield of three-step reaction reached to 80.4%.The method has the advantages of high yield,mild reaction conditions,and low environmental pressure compared with traditional industrial routes,which provides new ideas and lessons for the industrial production of albendazole.In second chapter,we analyzed the oxidation reaction of alcohols to the corresponding carboxylic acids by Acetobater.Meanwhile,we discussed the influences of solvent,cell concentration,p H of solution,reaction time and temperature on the yield,taking alcohols as substrate.The optimum conditions(temperature of 37?,pH 6,the amount of initial bacteria of 10~8/ml and substrate concentration of 10 g/L)have been found to achieve the highest yield and conversion.Furthermore,the pH was adjusted by hydrochloric acid.In order to investigate the selectivity of alcohol dehydrogenases and aldehyde dehydrogenase to substrate,the catalytic oxidation of primary alcohols and secondary alcohols with different structures has been performed.The results showed that besides to oxidizing ethylalcohol to acetic acid in vinegar industry,Acetobacter can directly oxidize alcohols to the corresponding acids without the accumulation of aldehydes under aerobic condition.However,it cannot oxidize secondary alcohols to the corresponding acids.The method for obtaining corresponding carboxylic acids by oxidizing primary alcohols with Acetobacter has the advantages of mild reaction condition,no pollution,low cost and easy operation.The product structures are identified by IR and ~1HNMR.In third chapter,we analyzed the reduction reaction by Bacillus cereus.Meanwhile,we discussed the influences of solvent,cell concentration,pH of solution,reaction time and temperature on the yield,taking aromatic nitro and oxime compounds as substrate.The optimum conditions(activation temperature of 30?,reaction temperature of 80?,pH 12,the amount of initial bacteria of10~8/ml and substrate concentration of 4 mmol)have been found to achieve the highest yield and conversion.Furthermore,the pH was adjusted by sodium hydroxide.In order to investigate the selectivity of Bacillus cereus to substrate,the catalytic reduction of aromatic aldehydes,ketone compounds with different structures has been performed.However,the results showed that the bacteria did not work.The method for obtaining corresponding aromatic amines by reducing aromatic nitro and oxime with Bacillus cereus provides a new way to preparation for primary amines.