Studies On The Synthesis And Antibiotic Activity Of The New N-alkylate Carbazole Compounds

Carbazole ring and Piperazine ring belong to the ring systems that exhibit good physiological activities,the biological activity of individual compound was greatly enhancd by organic combination of two nitrogen-containing heterocyclic compounds, carbazole compounds which was been modified by piperazine heterocyclic compounds are conceivable to obtain the potential drugs and pharmaceutical intermediates with excellent antibacterial activity. Synthesis of three new N-piperazine carbazole compounds of 9-(2-(4-methyl- piperazinyl-1-yl)ethyl)-9H-carbazole and 3,6-dibromo-9-(2-(4-methylpiperazinyl-1-yl)ethyl) -9H-carbazole and 3,6-Diochloro-9-(2-(4-methylpiperazinyl-1-yl)ethyl)-9H-carbazole were investigated in this paper.The chemical structures were determined by IR and 1HNMR, and had been carried on the antibacterial activity test.N-methyl-N'-(2-chloroethyl)piperazine was obtained by N-alkylation of N-methyl piperazine and 1,2-dichloroethane as the raw materials,The better technological conditions of the product's synthesis with 1,2-dichloroethane through the orthogonal experiment had been obtained, i.e. the molar ratio of N-methyl piperazine to 1,2-dichloroethane to N-dimethyl- formamide was 1:2:6.5, under the 50℃temperature the reaction time was 5 hours, ,the best yield of the product could reach 43.7% under this craft condition.Finally 9-(2-(4- methylpiperazinyl-1-yl)ethyl)-9H-carbazole was obtained by N-alkylation of carbazole and N-methyl-N'-(2-chloroeth-yl)piperazine as the raw materials, the yield of the product could reach 46.8%.3,6-Dibromo-carbazole was obtained by halogenation of carbazole and N-bromosuccini- mide as the raw materials, The better technological conditions of the product's synthesis with the aerosil law through the orthogonal experiment had been obtained, i.e. the molar ratio of carbazole to N-bromosuccinimide to solvent dichloromethane to catalyzer silica gel is 1:2:131:47,under the room temperature the reaction time was 12 hours, under this craft condition, the best yield of the structure could reach 89.3%. Finally 3,6-Dibromo-9-(2-(4 -methylpiperazinyl-1-yl)ethyl)-9H-carbazole was obtained by N-alkylation of 3,6-dibromo- carbazole and N-methyl-N'-(2-chloroeth-yl)piperazine as the raw materials, the yield of the product could reach 66.5%.3,6-Diochloro-carbazole was obtained by halogenation of carbazole and N- chlorosucci- nimide as the raw materials, Finally 3,6-Dibromo-9-(2-(4- methylpipera- zinyl-1-yl)ethyl)- 9H-carbazole was obtained by N-alkylation of 3,6-diochloro–carbazole and N-methyl-N'-(2- chloroeth-yl)piperazine as the raw materials, the yield of the product could reach 72.0%.The results of antibacterial activities of three new N-piperazine carbazole compounds to Escherichia coli(E.coli) indicate that 3,6-Diochloro-9-(2-(4- methylpiperazinyl-1-yl)ethyl) -9H-carbazole has almost antibacterial activity, and 3,6-Dibromo-9-(2-(4-methylpiperazinyl-1 -yl)ethyl)-9H-carbazole has weak antibac- terial activity,and 9-(2-(4-methyl piperazinyl-1- yl)ethyl)-9H-carbazole has better antibacterial activity which minimum inhibitory concentration(MIC) is 0.15mg/mL.