Catalytic Asymmetric Decarboxylative Mannich Reaction of Malonic Acid Half Esters with Cyclic Aldimines: Access to Chiral ß-Amino Esters and Chroman-4-amines.

An enantioselective decarboxylative Mannich reaction of malonic acid half esters (MAHEs) with cyclic aldimines has been accomplished by employing the copper(I)/(R,R)-Ph-Box complex as chiral catalyst. The desired ß-amino esters were obtained in good to high yields with excellent enantioselectivities. Furthermore, one of the corresponding Mannich products could be readily transformed into chiral chroman-4-amines without loss of enantioselectivity, which is a key intermediate of the human Bradykinin B1 receptor antagonist.

[Synthesis and Spectroscopic Study of a Chemosensor for Naked Eye Recognition of Cu2+ and Hg2+].

Compound L, as the procedural sensor for the detection of Cu2+ and Hg2+, was designed and synthesized based on the coumarin-modified rhodamine derivative. The structure of compound L was characterized by NMR, high resolution mass spectrometry and infrared method. Its sensing behavior toward various metal ions was investigated with absorbance methods. The study found that L had good selectivity and sensitivity for Cu2+. When addition of various metal ions (Zn2+, Hg2+, Cu2+, Fe3+, Cd2+, CO2+, Ni2+, Mg2+, Ca2+, Al3+, La3+, K+, Na+, Mn2+, Pb2+ and Ag+), only Cu2+ could induce a visible change of solution from colourless to pink and a new absorption band centered at 534 nm appear, which indicated that compound L could be used for the naked eye detection of Cu2+. From UV titration, the detection limit was about 1.9 X 10(-8) mol x L(-1). Test strips based on L were fabricated, and this test strips could act as a convenient and efficient Cu2+ test kit. The binding ratio of the complex of L-Cu2+ was 1:1 according to the Job's plot and high resolution mass spectrometer (HRMS) experiments. Moreover, Upon addition of 1 equiv. EDTA to the mixture of L and Cu2+ in DMSO solution, colour changed from pink to almost colourless, indicating that the EDTA replaced the receptor L to coordinate with Cu2+. Therefore, L could be classified as a reversible sensor for Cu2+. In addition, when adding Hg2+ to L-Cu2+ complexes, a visible change of solution from pink to colourless was observed, while other metal ions didn't cause this change. Thus, L-Cu2+ complex also could be used for the naked eye recognition of Hg2+, and the detection limit was calculated about 2.9 x 10(-1) mol x L(-1) according to the UV titration. Consequently, this procedural sensor L could be use for the orderly naked eye recognition of Cu2+ and Hg2+.

[Synthesis, characterization and interaction with ct-DNA of four novel secondary amine complexes].

A novel ligand(L), (N, N'-bis (4-methylbenzyl) ethane-1, 2-diamine), and its transition metal(II) complex, [ML2 (H2O)2]2+ x 2NO3- (M = Cu(II), Co(II, Ni(II), Zn(II)), have been synthesized and characterized by elemental analysis, IR and 1H NMR. The crystal structure of the Cu-L complex was characterized by X-ray single crystal diffraction, and the results showed a regular octahedral structure in which each metal ion is six--coordinated with four nitrogen atoms from two ligands and two oxygen atoms from two water molecules. The interaction of the complex with calf thymus DNA was investigated by UV spectroscopy and fluorescence spectroscopy, and the results suggest that the complex binds to DNA by electrostatic interaction mode. The binding constant(Cu-L, Co-L, Ni-L, Zn-L) was 1.67 x 10(3), 2.5 x 10(3), 1.35 x 10(3) and 9.85 x 10(2), respectively.

Bis(µ-N-benzyl-N-tetra-decyl-dithio-carbamato-κS:S')bis-[(N-benzyl-N-tetra-decyl-dithio-carbamato-κS,S')zinc(II)].

In the title compound, [Zn(2)(C(22)H(36)NS(2))(4)], two bidentate dithio-carbamate groups chelate directly to the Zn(II) atoms, whereas the two remaining dithio-carbamate ligands bridge the Zn atoms via a crystallographic inversion centre. The Zn atoms show a strongly distorted tetra-hedral geometry. Adding the long S⋯S distance with the inversion centre being in the middle, the resulting five-coordinate geometry around the Zn atoms can be considered to be between distorted recta-ngular pyramidal and trigonal bipyramidal, with a calculated τ value of 0.31. In this dimer complex, two inversion-related tetra-decyl carbon chains exhibit all-trans conformations, and the other two chains show a cis conformation at the end of the chains.