Novel Strategy For Synthesis Of 5,7-dichloroindole Derivatives

5, 7-dichloroindole derivatives are important organic materials and chemical intermediates. It has not only many special pharmacological effects, such as HIV treatment, but could also be used as growth hormone for plants, addictives of feeding stuff. Therefore, it could be widely used in the areas of agriculture and medicine. However, only a few synthetic methods with disadvantages are reported by now. So it is necessary to come out a new way to get such product.In this research, one pot react 2, 4-dichloro-6-iodoanline and carbonyl compound to get our desired 5, 7-dichloroindole ring structure, and it is convenient to get such product, which simplifies the whole reaction to two steps. It would saving the reacting materials and lessen the work intensity.2, 4-dichloroanline was as the starting materials to synthesize cyclizaion substrate 2, 4-dichloro-6-iodoanline by introducing a iodo atom into the 6th position of anline compounds. Two different iodination methods, ICl iodination and Oxidative iodination, were compared to choose the best one.About the annulation of 5, 7-dichloroindole derivatives, we performed the reaction of 2, 4-dichloro-6-iodoanline and pyruvic acid to get 5,7-dichloroindole -2-carboxylic acid, which was characterized by ¹H-NMR and FT-IR. The optimized conditions is obtained as following: the ratio of Pd(OAc₂)(3mol%) to P(o-tol)₃ is 1:2, reaction time 5h, reaction temperature about 80℃, and ethylamine as base.