| In this thesis, the process for preparation of halogen substituted aromatic acids and its derivatives have been developed from halogen substituted o-nitro toluene.Firstly, the process for halogen substituted aromatic acids in ethanol-water under alkaline condition has been investigated. Through the optimization of oxidation-reduction conditions, the optimal conditions were set as sodium hydroxide concentration 40%,2.5 equivalents of sodium hydroxide, ethanol concentration 60%(v/v). Under the optimal conditions, a 65% yield of 4-halo-2-amino-benzoic acid was obtained. Further, the yield increased to 86% using autoclave under IMPa.Secondly, the method of making amino benzaldehyde in an aqueous alcoholic solution using sodium polysulfide from the halogen substitute nitro toluene was adopted to the reaction of halogen substituted o-nitro toluene. A one pot synthesis of quinoline derivatives has been developed by adding acetone to the oxidation-reduction product, o-amino benzaldehyde, under the optimized oxidation-reduction conditions. The optimal condition has been set as sodium hydroxide concentration 6%,1 equivalent of sodium tetrasulfide aqueous solution(0.38mol/L),0.2 equivalents of N, N'-dimethylformamide. Under the optimal conditions, the halogen substituted quinoline could be obtained in 25% yield along with a about 50% yield of halogen substituted aniline. The scope of the procedure was also explored to develop a process potentially suitable for large scale preparation. |
