Pinacol coupling reactions catalyzed by active zinc revealed high activity and extensive suitability. The efficiency of the reaction was improved apparently owing to decreasing reductive potential of zinc. In addition, the results indicated that the zinc activity has a direct relation to the coupling reactivity compared to untreated zinc or other general active zinc.
A number of naphthalene derivatives containing adamantanamine binding moiety and an （CH2）. （n = 2, 3, 4, 5, 6） spacer were prepared as electron donor. A supramolecular assembly was fabricated by the inclusion complexation of the donor substrates with the host molecules, mono-6-O-p-nitrobenzoyl-β-cyclodextrin （p-NBCD） and mono-6-O-m-nitrobenzoyl-β-cyclodextrin （m-NBCD）, in water. The fluorescence quenching in these systems was studied and detailed Stern-Volmer constants were measured. It revealed that an efficient photoinduced electron transfers （PET） between the naphthalene donors and the cyclodextrin acceptors occurred.
Hui Yuan HU Man Zhou ZHU Zhi Ping ZHANG Guo Tao WEN Qing Xiang GUO
An operationally simple and inexpensive catalyst system was developed for the cross coupling of potassium thiocyanate with aryl iodides by using CuI as catalyst, 1, 10-phenanthroline as ligand, and tetraethylammonium iodide as activator. The procedure is applicable for the synthesis of diverse aryl thiocyanates without any exotic, poisonous reagents.
Ye Feng WANG Yuan ZHOU Jia Rui WANG Lei LIU Qing Xiang GUO
An operationally simple and inexpensive catalyst system was developed for the cross coupling of aryl iodides and bromides with ethyl acetoacetate by using CuI as catalyst and Nmethyl glycine as ligand. The reaction represents a novel Cu-catalyzed C-C cross coupling reaction. This procedure is applicable to the preparation of pharmaceutically important α- arylalkanoic acids.
A novel fluorescent Hg^2＋ chemosensor based on dithia-dioxa-monoaza crown ether was synthesized in four steps from inexpensive starting materials. This new sensor exhibited very strong fluorescence response to Hg^2＋ （FHg^2＋/Ffree 〉 130） and it was highly selective to Hg^2＋ over the other metal ions by more than 45-fold.
Ma＇s CuI/proline procedure for the catalytic cross coupling between nitrogen heterocycles and aryl halides was markedly improved. The key finding was that K3PO4 was a much better base than K2CO3 for the reaction. With this new reaction condition the cross coupling with aryl iodides could be accomplished in 1,4-dioxane instead of DMSO. This reactin also could be carried out in DMF. Furthermore, the coupling yields under the new conditions are usually higher than in Ma＇s original methods.
Wei DENG Ye Feng WANG Chen ZHANG Lei LIU Qing Xiang GUO
A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the efficient intramolecular photoinduced electron transfer （PET）. However, after addition of the transition metal ions, the chemoscnsor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn^2＋ and Cd^2＋. The fluorescent chemosensors with different polyamine as receptors show diverse affinity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission.
In this article, a general, simple, and inexpensive catalyst system was developed for the amidation of aryl bromide by using CuI as catalyst, amino acid as ligand, and K3PO4 as base.
