Zhonglu You

Inhibition studies of Helicobacter pylori urease with Schiff base copper(II) complexes

Nine new copper(II) complexes derived from various Schiff bases were prepared. They are [Cu2Br2(L1)2] (1), [Cu(L2)2]·2NO3·2CH3OH (2), [Cu(L3)2]·2Br (3), [Cu(L4)2] (4), [Cu2Cl4(L2)2] (5), [Cu2Cl2(L5)2] (6), [CuL6(NCS)] (7), [CuClL6]·CH3OH (8), and [Cu2(L7)2] (9), where L1 is the monoanionic form of 2-chloro-N′-(4-diethylamino-2-hydroxybenzylidene)benzohydrazide (HL1), L2 is the zwitterionic form of 4-methyl-2-((3-morpholinopropylimino)methyl)phenol (L2), L3 is the zwitterionic form of 2-bromo-4-chloro-6-((2-(2-hydroxyethylamino)ethylimino)methyl)phenol (L3), L4 is the monoanionic form of 2-bromo-4-chloro-6-((cyclopentylimino)methyl)phenol (HL4), L5 is the monoanionic form of 2-((cyclopropylimino)methyl)-4-methylphenol (HL5), L6 is the monoanionic form of 4-methyl-2-((pyridin-2-ylmethylimino)methyl)phenol (HL6), and L7 is the dianionic form of N,N′-bis(5-methylsalicylidene)-1,4-diiminobutane (H2L7). The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Cu atoms in complex 1 display square pyramidal coordination, in complex 5 display trigonal bipyramidal coordination, in complex 9 show tetrahedrally distorted square planar coordination, and in the remaining complexes display square planar coordination. Complexes 2, 3, 5, 7 and 8 show effective urease inhibitory activities, with IC50 values of 0.37 ± 1.22, 0.21 ± 0.97, 0.03 ± 0.78, 0.39 ± 0.58 and 0.76 ± 0.95 μM, respectively. Molecular docking study of the complexes with Helicobacter pylori urease was performed. Complex 5 has the most effective activity against urease, with a mixed competitive inhibition mechanism. The complex interacts with the nickel atom of the urease active center, and with the remaining parts of the complex molecule block the entrance of the urease active pocket.

Syntheses, Crystal Structures and Antimicrobial Activities of Vanadium(V) Complexes with Similar Tridentate Hydrazone Ligands ①

Two new oxovanadium(V) complexes, [VOL1(OEt)(EtOH)] (1) and [VOL2(OMe)(MeOH)] (2), were prepared by reaction of [VO(acac)2] (where acac = acetylacetonate) with N′-(3-bromo-2-hydroxybenzylidene)-4-methylbenzohydrazide (H2L1) in ethanol and N′-(3-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2L2) in methanol, respectively. Crystal and molecular structures of the complexes were determined by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. The V ions have octahedral coordination. Thermal stability and the inhibition of urease of the complexes were studied. Graphical Abstract

(E)-N′-(5-Bromo-2-hy­droxy­benzyl­idene)-4-hy­droxy-3-meth­oxy­benzohydrazide methanol solvate

In the title compound, C15H13BrN2O4·CH4O, the two benzene rings form a dihedral angle of 3.2 (2)°. An intramolecular O—H⋯N hydrogen bond is observed. In the crystal structure, molecules are linked through O—H⋯O and N—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (10).

(E)-N′-(4-Hy­droxy­benzyl­idene)-2-nitro­benzohydrazide

In the title compound, C14H11N3O4, the two benzene rings form a dihedral angle of 45.3 (3)°. The nitro group is twisted out of the attached ring by a dihedral angle of 37.5 (3)°. In the crystal structure, molecules are linked into a two-dimensional network parallel to (100) by O—H⋯O and N—H⋯O hydrogen bonds.

Synthesis, crystal structures and Jack bean urease inhibitory activity of copper(II) complexes with 4-bromo-N′-(2-hydroxy-5-methoxybenzylidene)benzohydrazide

Abstract A new hydrazone 4-bromo-N′-(2-hydroxy-5-methoxybenzylidene)benzohydrazide (HL) was prepared and characterized by infrared and UV–vis spectra, as well as single-crystal X-ray diffraction. With the hydrazone as ligand, two new copper(II) complexes were prepared, [Cu2L2(NCS)2]·4H2O (1) and [CuBrL]·CH3OH (2). The complexes were characterized by infrared and UV–vis spectra, and single-crystal X-ray diffraction. The Cu in 1 is in a square pyramidal coordination geometry and that in 2 is in a square planar coordination geometry. The two complexes show effective Jack bean urease inhibitory activity, with IC50 values of 23.5 and 2.7 μM, respectively. A molecular docking study of 2 with the urease was performed. The relationship between the structure and urease inhibitory activity indicated that copper complex with square planar coordination is a better model for urease inhibition.

Synthesis, structures, and insulin-like activity of oxidovanadium(V) complexes derived from 2-chloro-N′-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide

Abstract Three new oxidovanadium(V) complexes, [VOLL′] (L = 2-chloro-N′-(3-ethoxy-2hydroxybenzylidene)benzohydrazide, L′ = acetohydroxamate for 1, methylmaltolate for 2, and ethylmaltolate for 3), have been prepared. The complexes have been characterized by physicochemical methods and single-crystal X-ray determination. Vanadium in each complex is coordinated by the NOO donor set of L, the OO donor set of L′, and one oxido, forming octahedral coordination. The complexes were administered intragastrically to both normal and alloxan-diabetic mice for two weeks. The biological activities show that the complexes at doses of 10.0 and 20.0 mg V·kg−1 can significantly decrease the blood glucose level in alloxan-diabetic mice, but the blood glucose level in the treated normal mice was not altered.

Synthesis, crystal structure, and Helicobacter pylori urease inhibition of a dicyanoamide bridged Cu(I/II) complex

Abstract A dicyanoamide-bridged polymeric copper(I/II) complex, [CuII(sal)(bipy)CuI(dca)2]n, was prepared by reaction of 5-methylchlorosalicylaldehyde (Hsal), 2,2′-bipyridine (bipy), sodium dicyanoamide (Nadca), and copper perchlorate in methanol. The complex was characterized by elemental analyses, infrared and electronic spectroscopy, and single-crystal X-ray determination. CuII has a square pyramidal coordination, and CuI has triangular coordination. The complex showed high urease inhibitory activity with IC50 value of 0.16 ± 0.23 μM.

Synthesis and Crystal Structure of a μ-Oxido-Bridged Dinuclear Iron(III) Complex Derived From 3, 5-Dichlorosalicylaldehyde and 4-(2-Aminoethyl)morpholine

A μ-oxido-bridged dinuclear iron(III) complex, [Fe2O(L1)2(L2)2], where L1 and L2 are the deprotonated forms of 2,4-dichloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol and 3,5-dichlorosalicylaldehyde, respectively, has been prepared and characterized by elemental analysis, infrared spectrum, and single-crystal X-ray determination. The complex crystallizes in the triclinic space group P, with unit cell dimensions a = 10.670(1) Å, b = 11.585(1) Å, c = 19.748(2) Å, α = 86.766(2)°, β = 85.038(2)°, γ = 73.973(2)°, V = 2336.1(4) Å3, Z = 2, GOOF = 1.019, R1 = 0.0422, and wR2 = 0.1024. Structural analysis shows that the iron atoms in the complex are hexacoordinate with a normal Fe-O-Fe bridging angle of 150.84(13)°. Each Fe atom is coordinated by the NNO donor atoms of L1, OO donor atoms of L2, and one bridging O atom. The Fe· · ·Fe distance is 3.467(2) Å.

Bis­[2-(o-tolyl­imino­methyl)­phenolato]copper(II)

The title compound, [Cu(C14H12NO)2], is a mononuclear copper(II) compound. The CuII atom, lying on a centre of symmetry, is four-coordinated by two N atoms and two O atoms from two Schiff base ligands, giving a square-planar geometry.

Syntheses, crystal structures, and Jack bean urease inhibitory activities of copper(II) complexes derived from 4-tert-butyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide

Abstract Two new copper(II) complexes, [CuL(HL)]·ClO4 (1) and [Cu2Br2L2]·0.85H2O (2), where L is the monoanionic form of 4-tert-butyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL), have been prepared. The complexes were characterized by infrared and UV–vis spectra, and single crystal X-ray diffraction. Complex 1 is a mononuclear copper(II) species and 2 is a bromido-bridged dinuclear copper(II) species. The Cu ion in 1 is in an octahedral coordination mode and that in 2 is trigonal-bipyramidal. The Jack bean urease inhibitory assay indicated that 2 is active, with IC50 value of 20.6 ± 2.3 μmol L−1, while 1 is inactive. Molecular docking of 2 with Jack bean urease was studied.