| The researches detailed in this thesis were as follows:(1) A review on the Suzuki coupling reactions was made;(2) The method for the syntheis of 3-aryl(heteroaryl)-5- amine- pyridazine and 3-aryl(heteroaryl)-4,5-dimethoxy-pyridazine via Suzuki coupling reaction was first reported;(3) An optimum catalystic system, which is very easy, efficent and can be used to many chloro-substituted pyridazine substrates was found. The best reaction conditions were 3- chloro- 6-methoxypyridazine (1.0equiv.),6-butoxy pyridine-3-y1-boronic acid (2.0equiv.), K2CO3(2.0equiv.), palladium(II) acetate (2% equiv.) and triphenylphosphane (4% equiv.), N2 atmosphere, in toluene and ethanol (v/v,2:1) at oil bath 110℃.(4) The efficiency of the catalyst system was confirmed. The scope of the reaction was tested under the best conditions with some pyridine boronic acid and some phenyl boronic acid, and we found that the reactivity of 2- or 4-pyridine boronic acid was lower than 3- or 5-pyridine boronic acid; and alkyloxy-substituted pyridine boronic acid was more reactive than aryloxy-substituted pyridine acid. In addition, the substitutes on phenyl boronic acid had nearly no effect on 3,6-di-substituted pyridazine, but for 3-chloro-5-aminepyridazine or 3-chloro-4,5-dimethoxy pyridazine, there were some effects. Otherwise, the position of the substitutes on the cycle of pyridazine had effect on the reactivity. According to the investigation,3-chloro-6-amine - pyridazine was more reactive than 3-chloro-5-aminepyridazine, and 3-chloro-6-methoxypyridazine was more reactive than 3-chloro-4,5-dimethoxy pyridazine.(5) 3,5-dichloro-4-aminepyridazine could reacted with phenyl boronic acid under the ratio 1:1, to synthesis 5-chloro-4- amine-3- phenylpyridazine with high selectivity, the isolated yield was 80%. |
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