《Table 2 C—N coupling reaction catalyzed by Chi-Gly@CuIa》

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《交联壳聚糖微球负载铜水相催化Ullmann反应（英文）》

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Cross-linked chitosan beads supported copper complex was prepared as shown in Figure 1.In order to evaluate the catalytic performances of cross-linked chitosan beads supported copper complex and acquire the optimized reaction conditions，the model reaction of iodobenzene with imidazole in water was studied.More detailed results were summarized in Table 1.First，only using CuI as the catalyst，no product was observed（Table 1，Entry 1）.A series of uncross-clinked chitosan beads supported copper complexes were tested（Table 1，Entries 2～6）.It was found that all these copper sources supported by chitosan displayed good catalytic effects in this model reaction.Among above mentioned catalysts，Chi@CuBr exhibited the best activity with 82%yield.Furthermore，a preliminary comparison of the model reaction catalyzed by uncross-clinked chitosan beads supported copper with the one catalyzed by crossclinked chitosan beads supported copper indicates that the cross-clinked chitosan further promotes the activity of copper source（Table 1，Entries 2～16）.Two cross-linking agents，glyoxal and glutaraldehyde，were examined and Chi-Gly@CuI exhibited a superior performance with the highest yield of 97%.Moreover，no products were detected when Chi-Gly and CuI were added into the reaction（Table1，Entries 1，17）.Thus，Chi-Gly@CuI was selected for further investigation.Next，a series of bases，e.g.Na2CO3，KOH，K2CO3，Cs2CO3，NaOAc，KHCO3，Et3N，and NaHCO3，were tested.When all bases played role in this reaction，Na2CO3 was found to be the best and excellent yield was achieved（Table 1，Entries 7，18～25）.With regard to temperature and time，they also affected much to the model reaction（Table 1，Entries 26～28），the reaction at 100℃gave the highest yield and 24 h was applicable reaction time.Finally，the optimum conditions can be concluded:using Na2CO3 as a base，water as a solvent，ChiGly@Cu I as the catalyst，100℃，24 h.A further extensive investigation was carried out on these conditions with ChiGly@Cu I as the catalyst.