Suzuki Coupling Reaction Of Pyrazine Derivatives

In this thesis,2-chloro-6-ethoxypyrazine (la) and 4-methoxyphenylboronic acid coupling reaction as a template to study the conditions change on the reaction, as shown below.Suzuki coupling reaction is more common carbon-carbon bond formation one way, the basic factors affecting the reaction include alkali, catalyst, ligand, solvent, etc., this paper based on the existing work to the template reaction cases, a series of exploration and research, and ultimately optimize the reaction conditions, with the existing conditions of the coupling reaction compared to the condition reduces the amount of catalyst, reaction time shortened to obtain a higher yield. Then the template substrate reaction with different boric acid, boric acid and ester reaction of pyridine, the corresponding yield obtained to study the law. Experimental results show that 2-chloro-6-ethoxypyrazine with aryl acid chloride generation rates even higher and less sensitive to the steric hindrance, if the benzene ring connected to the strong electron withdrawing group, the production rate in low; and pyridine borate coupling in moderate yields.On this basis, respectively,2-chloro-6-isopropoxy pyrazine (2a), 6-chloropyrazin-2-amine (3a),2,6-dichloro-pyrazine (4a) for the coupling substrate, the reaction conditions have been optimized, will the typical coupling of aryl boronic acid, the yield obtained to study the response characteristics. Finally, summarized:the conditions have been optimized for the substrate (la), (2a), (3a) with aryl boronic acid coupling of high yield and the yield of pyridine boronic acid coupling in general, if the benzene ring with strong electron withdrawing group, the yield is poor. Substrate for the 2,6-dichloro-pyrazine (4a) of the low yield SUZUKI coupling reaction, the optimal conditions for the compatibility is poor. Coupling product after 1H NMR,13C NMR proved...